Written Comments of the United States of America

INTERNATIONAL COURT OF JUSTICE
REQUEST BY THE UNITED NATIONS GENERAL ASSEMBLY
FOR AN ADVISORY OPINION ON THE
“LEGAL CONSEQUENCES OF THE SEPARATION OF THE CHAGOS
ARCHIPELAGO FROM MAURITIUS IN 1965”
WRITTEN COMMENTS OF
THE UNITED STATES OF AMERICA
MAY 15, 2018

TABLE OF CONTENTS
CHAPTER I – INTRODUCTION .............................................................................1
CHAPTER II – THE COURT’S DISCRETION NOT TO RESPOND TO THE
GENERAL ASSEMBLY’S REQUEST ....................................................................4
A. The questions referred are directly related to a pending bilateral territorial dispute
between Mauritius and the United Kingdom...................................................................... 6
B. The Court’s jurisprudence reaffirms the serious concerns inherent in rendering an
advisory opinion about a bilateral territorial dispute absent the consent of the parties
to the dispute. ...................................................................................................................... 7
C. No other factor identified justifies dispensing with the serious concerns of judicial
propriety implicated by this request..................................................................................10
D. The principle of consent commands particular respect when the request relates to a
dispute involving sovereignty over territory.....................................................................14
CHAPTER III – CONSIDERATIONS RELATING TO THE QUESTIONS
REFERRED .............................................................................................................15
A. The Court would need to examine the historical record through the lens of the
established sources of international law, as set forth in its Statute and elaborated in its
jurisprudence....................................................................................................................16
B. The sources cited by the written statements asserting that a rule of customary
international law had emerged do not support that conclusion.........................................19
C. There was no rule of customary international law that would have required the United
Kingdom to hold a plebiscite prior to Mauritius’s independence.....................................32
CHAPTER IV – FURTHER OBSERVATIONS.....................................................36
CHAPTER V – CONCLUSION ..............................................................................40

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CHAPTER I
INTRODUCTION
1.1 In accordance with the Court’s Orders of July 14, 2017, and January 17, 2018, the
United States hereby presents its Written Comments in response to the written statements
submitted by other States and organizations on and before March 1, 2018. The United States
again conveys its appreciation to the Court for the opportunity to furnish its observations.
1.2 In its Written Statement of March 1, 2018, the United States identified the compelling
reasons why the Court should decline to provide an advisory opinion in this case. Having
carefully considered all of the written statements submitted to the Court, the United States
reaffirms its position that the Court should decline to exercise its advisory jurisdiction over
this matter.
1.3 This case presents fundamental challenges to the integrity of the Court’s judicial
function and invites the Court to delve into and reach conclusions on a wide range of legal
issues related to an ongoing bilateral dispute between Mauritius and the United Kingdom.
1.4 To recall, in its resolution 71/292, the General Assembly requested the Court to
render an advisory opinion on two questions:
(a) Was the process of decolonization of Mauritius lawfully completed when Mauritius
was granted independence in 1968, following the separation of the Chagos
Archipelago from Mauritius and having regard to international law, including
obligations reflected in General Assembly resolutions 1514 (XV) of 14 December
1960, 2066 (XX) of 16 December 1965, 2232 (XXI) of 20 December 1966 and 2357
(XXII) of 19 December 1967?
(b) What are the consequences under international law, including obligations reflected in
the above-mentioned resolutions, arising from the continued administration by the
United Kingdom of Great Britain and Northern Ireland of the Chagos Archipelago,
including with respect to the inability of Mauritius to implement a programme for the
resettlement on the Chagos Archipelago of its nationals, in particular those of
Chagossian origin?
1.5 Chapter II begins by highlighting important points of agreement among the written
statements, including with respect to the circumstances that would warrant the Court’s
exercise of its discretion to decline to respond to the General Assembly’s request. Those very
circumstances are evident in this case, since the questions referred focus on a bilateral
territorial dispute between Mauritius and the United Kingdom. Unless the Court can avoid
addressing that dispute—which is difficult to imagine—responding to the request would
circumvent the fundamental principle that a State is not obliged to submit its disputes for
adjudication without its consent.
1.6 Chapter II then explains why none of the arguments in favor of responding to the
questions referred dispense with the very serious concerns regarding the propriety of utilizing
the Court’s advisory jurisdiction in a case that is, at its core, about an ongoing bilateral
sovereignty dispute. There does not appear to be any disagreement in the written statements
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that this case bears directly on such a dispute. Indeed, many of the written statements affirm
this reality, some going so far as to endorse the resort to the Court’s advisory jurisdiction as
an effort to resolve that sovereignty dispute. The United States and a number of other States,
however, have underscored that the Court must proceed with great caution in the face of such
an overt effort to circumvent the fundamental principle of consent to judicial settlement.1
Some States, including the United States, also cautioned that doing so could have the effect
of blurring the deliberate distinction that was created between the Court’s consent-based
contentious jurisdiction and its advisory jurisdiction.2
1.7 For these reasons, as the United States observed in its Written Statement, it is
incumbent upon the Court to determine whether it could answer Question (a) in a manner
consistent with the principle of consent to judicial settlement.
1.8 There is no doubt that answering Question (a) would embroil the Court in a bilateral
dispute and that the United Kingdom has not consented to judicial settlement of that dispute
by this Court. Of particular note, a number of the written statements acknowledge that the
separation of the Chagos Archipelago would not have been unlawful if it reflected the free
consent of the people of the territory.3 For its part, Mauritius suggests that the agreement,
which both parties reaffirmed after Mauritius’s independence, and which an arbitral tribunal
concluded gave rise to binding obligations between the two States, did not or could not reflect
such consent.4 But, as discussed in Chapter II, it would be inappropriate for the Court to
conduct, in these advisory proceedings, an assessment of the validity of a bilateral
agreement.5
1.9 The position of the United States thus remains that the Court should decline to
respond to the questions posed. That said, should the Court choose to respond to Question (a),
the answer should be that the process of decolonization of Mauritius was lawfully completed
in 1968. In its Written Statement, the United States set forth its analysis as to why the
historical record supports this conclusion.6
1.10 In Chapter III, the United States responds to arguments made in some of the written
statements about whether international law supplied a rule at the relevant time that would
have prohibited the establishment of the British Indian Ocean Territory (BIOT).
1.11 Were it to answer Question (a), the Court would need to ascertain the law as it existed
at the relevant time.7 The written statements that addressed this issue generally agree that the
relevant time would have been 1965 (when the United Kingdom established the BIOT) or, at
1 See infra para. 2.3.
2 See, e.g., Australia Written Statement, paras. 40–44; Germany Written Statement, para. 37; United States
Written Statement, para. 5.1.
3 See infra para. 3.49 n. 137.
4 Mauritius Written Statement, paras. 1.41(vi), 6.3(6).
5 See infra para. 2.10.
6 United States Written Statement, ch. IV.
7 Id., paras. 4.23–4.24; infra paras. 3.11–3.15.
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the latest, 1968 (when Mauritius gained its independence),8 but present a range of views as to
the state of the relevant law and how the Court might determine it.
1.12 Most of those submissions either did not accurately describe how the Court would
determine a relevant rule of customary international law or drew incorrect conclusions from
the historical record about state practice and States’ contemporaneous beliefs about the law.
As such, the submissions failed to demonstrate that a specific legal obligation existed at the
relevant time that would have made the establishment of the BIOT unlawful.
1.13 Implicit in the way the various written statements approach the questions referred is a
common understanding that the answer to Question (b) is linked to Question (a).9 This
understanding supports the conclusion, as the United States explained in its Written
Statement,10 that if the Court either cannot, for reasons of propriety or otherwise, provide an
answer to Question (a), or if its answers Question (a) in the affirmative (i.e., that the
decolonization of Mauritius was lawfully completed in 1968), there is no need to answer
Question (b).
1.14 The United States therefore does not deem it necessary to address Question (b) in any
detail. Instead, in Chapter IV, the United States offers several observations on others’ written
statements, including identifying some assumptions that present an overly simplistic or
incomplete view of the complex set of issues involved.
1.15 Chapter V concludes by again urging that the Court, in order to preserve the integrity
of its judicial function, decline to respond to the request for an advisory opinion. The written
statements submitted to the Court differ on the appropriate response to this request. But there
is no disagreement that the questions bear directly and significantly on an ongoing bilateral
sovereignty dispute over territory. Attempts to present the legal questions that are at issue in
this dispute as ones that might guide the General Assembly in the exercise of its
decolonization mandate neither alters that reality, nor displaces the principle of consent to
judicial settlement as an important constraint on the Court’s advisory jurisdiction.
8 See infra para. 3.3.
9 See, e.g., Mauritius Written Statement, para. 1.40 (noting that the response to the second question is
“inextricably connected to the first question”); African Union Written Statement, para. 33 (describing the
questions as “interdependent, complementary”).
10 United States Written Statement, paras. 4.17, 4.75.
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CHAPTER II
THE COURT’S DISCRETION NOT TO RESPOND TO
THE GENERAL ASSEMBLY’S REQUEST
2.1 As States acknowledged in their written statements, the Court’s authority to issue an
advisory opinion is discretionary,11 and the Court has “a duty to satisfy itself, each time it is
seised of a request for an opinion, as to the propriety of the exercise of its judicial
function.”12
2.2 In those written statements that addressed the Court’s exercise of its discretion, there
was general agreement on three additional points:
(a) The Court, while mindful of its duties as the principal judicial organ of the United
Nations, has nevertheless recognized that there may be “compelling reasons” that
should lead it to decline a request for an advisory opinion.13
(b) One such compelling reason is when the circumstances disclose that to give a reply
“would have the effect of circumventing the principle that a State is not obliged to
allow its disputes to be submitted to judicial settlement without its consent.”14
(c) The questions referred relate to an ongoing bilateral dispute concerning sovereignty
over territory and one party to that dispute has not consented to judicial settlement of
the dispute by this Court.15
11 See, e.g., Australia Written Statement, para. 27; Brazil Written Statement, para. 9; China Written Statement,
para. 16; Djibouti Written Statement, para. 19; France Written Statement, paras. 4–5; Germany Written
Statement, para. 22; Guatemala Written Statement, para. 19; Israel Written Statement, para. 2.1; Liechtenstein
Written Statement, para. 14; Mauritius Written Statement, para. 5.18; Republic of Korea Written Statement,
para. 7; Russian Federation Written Statement, para. 11; Serbia Written Statement, para. 19; South Africa
Written Statement, para. 50; United Kingdom Written Statement, para. 7.1.
12 Legal Consequences of the Construction of a Wall in the Occupied Palestinian Territory, Advisory Opinion,
I.C.J. Reports 2004, p. 136 [hereinafter Construction of a Wall], para. 45.
13 See, e.g., African Union Written Statement, paras. 37, 53; Australia Written Statement, para. 28; Cyprus
Written Statement, para. 19; Djibouti Written Statement, para. 19; France Written Statement, para. 5; Israel
Written Statement, para. 2.3; Liechtenstein Written Statement, para. 15; Marshall Islands Written Statement,
para. 14; Mauritius Written Statement, para. 5.19; Republic of Korea Written Statement, para. 7; Serbia Written
Statement, para. 19; South Africa Written Statement, para. 54; United Kingdom Written Statement, para. 7.10;
United States Written Statement, para. 3.3.
14 Western Sahara, Advisory Opinion, I.C.J. Reports 1975, p. 12 [hereinafter Western Sahara], paras. 32–33. See
African Union Written Statement, paras. 205–06; Argentina Written Statement, para. 26; Australia Written
Statement, paras. 35–36; Brazil Written Statement, para. 11; Chile Written Statement, para. 5; China Written
Statement, para. 16; Cyprus Written Statement, para. 24; Djibouti Written Statement, para. 23; France Written
Statement, para. 7; Germany Written Statement, paras. 34–36; Guatemala Written Statement, para. 26; Israel
Written Statement, para. 3.1; Mauritius Written Statement, para. 5.29; Republic of Korea Written Statement,
para. 12; Russian Federation Written Statement, paras. 29–30; South Africa Written Statement, para. 43; United
Kingdom Written Statement, para. 7.15(e); United States Written Statement, para. 3.3.
15 See, e.g., Argentina Written Statement, para. 23 (acknowledging that the dispute is “on matters directly related
to the questions put by the General Assembly to the Court”); Australia Written Statement, para. 5 (“The request
from the General Assembly in reality seeks to have the Court adjudicate upon a preexisting bilateral dispute
between the United Kingdom and Mauritius … .”); Chile Written Statement, para. 5 (“Chile is aware of the fact
that the request for an advisory opinion relates to a territorial dispute arising between Mauritius and the United
Kingdom, which does not recognize the jurisdiction of the Court to settle it … .”); China Written Statement,
para. 19 (“China encourages and calls upon States concerned to act in good faith, and seek appropriate
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2.3 It is true that the present Court has not exercised its discretion to decline to answer a
request for an advisory opinion from the General Assembly. But the circumstances of this
case present the exact and compelling reasons that the Court has indicated in its prior
opinions should lead it to decline to respond. It is difficult to see how the Court could respond
to the questions referred without going directly to the crux of an ongoing bilateral dispute
over territorial sovereignty. A number of States—namely Australia, Chile, China, France,
Germany, Israel, the Republic of Korea, the Russian Federation, the United Kingdom, and the
United States—all urged the Court to exercise caution so as to avoid responding in a manner
that would be tantamount to adjudicating the underlying sovereignty dispute or prejudicing
the legal positions of the parties to that dispute.
2.4 This chapter begins in Section A by describing the extent to which the written
statements confirm the direct relationship between this request for an advisory opinion and
the underlying territorial dispute between Mauritius and the United Kingdom. Section B then
turns to the Court’s jurisprudence as it relates to the application of the fundamental principle
of consent to judicial settlement in the advisory opinion context, with a particular emphasis
on the Court’s opinion in Western Sahara. Section C explains that no other factor raised in
the written statements—in particular the erga omnes character of obligations arising from
self-determination or the General Assembly’s purported interest in the bilateral dispute over
the status of the Chagos Archipelago—justifies dispensing with the serious concerns of
judicial propriety that this request presents. Section D reiterates that the principle of consent
to judicial settlement commands particular respect where a request relates to a territorial
sovereignty dispute.
solution[s] to relevant issues through negotiation or any other peaceful means agreed to by both parties.”);
France Written Statement, paras. 15–19 (noting that the object of the request was to resolve a dispute between
the two concerned parties); Germany Written Statement, para. 34 (noting that “the Court cannot decide on the
bilateral dispute which forms the background of the request for an advisory opinion under its contentious
jurisdiction, given the overarching principle of consent which governs the exercise of the Court’s contentious
jurisdiction”); India Written Statement, para. 8 (noting that Mauritius decided to refer its territorial dispute with
the United Kingdom over the Chagos Archipelago through the General Assembly to the Court for an advisory
opinion); Israel Written Statement, para. 3.8 (“Mauritius has openly acknowledged that the present advisory
proceedings were sought precisely because the bilateral negotiations aimed at settling its dispute with the United
Kingdom have, in its view, failed.”); Marshall Islands Written Statement, para. 15 (noting that the issue is not
limited to a “purely bilateral dimension—even as the overall political issue of the Chagos situation has
important (if not key) bilateral aspects”); Russian Federation Written Statement, para. 32 (noting that the criteria
for exercising discretion if a request for an advisory opinion involves a bilateral territorial dispute “must be even
higher”); United Kingdom Written Statement, para. 7.16 (noting that the request “requires the Court to engage
in … matters that have long been in issue as part of a bilateral dispute”); United States Written Statement, para.
1.2 (noting that “[t]he United States voted against the General Assembly’s referral resolution because it
concerns a bilateral territorial dispute between Mauritius and the United Kingdom concerning sovereignty over
the Chagos Archipelago”).
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A. The questions referred are directly related to a pending bilateral territorial
dispute between Mauritius and the United Kingdom.
2.5 The submissions of other States—in particular those of Mauritius and the United
Kingdom—make plain that the questions referred are directly related to core aspects of the
underlying bilateral dispute concerning sovereignty over the Chagos Archipelago.16
2.6 The statements also reveal the degree to which the parties’ legal positions in the
current proceedings echo those previously presented by the same parties during contentious
proceedings in the Chagos Marine Protected Area Arbitration.17
2.7 The direct relationship between the questions referred and the bilateral territorial
dispute is particularly evident with respect to a central issue on which Mauritius and the
United Kingdom disagree—the legal status of the bilateral agreement they reached in 1965
concerning the Chagos Archipelago, and which they subsequently affirmed by a series of
statements and actions until at least 1980.
2.8 A key element of the ongoing bilateral dispute is whether that 1965 agreement and
subsequent affirmations reflect the valid consent of Mauritius to the establishment of the
BIOT, subject to certain negotiated conditions on the management and future disposition of
the Chagos Archipelago. The written statements of Mauritius and the United Kingdom reveal
the depth of their disagreement over this and related issues.18
16 See, e.g., Mauritius Written Statement, p. 285 (seeking a finding from the Court that the process of
decolonization of Mauritius was not lawfully completed, and that as a consequence Mauritius should be able to
exercise sovereignty over the Chagos Archipelago); United Kingdom Written Statement, para. 1.2
(characterizing the dispute over the Chagos Archipelago, in particular as to sovereignty, as “the central issue
behind the Request for an advisory opinion”).
17 Compare Mauritius Written Statement, para. 6.63 (“Thus, in the case of Mauritius, the unit of selfdetermination—
in relation to which the administering power owed the duty to accord the right of selfdetermination—
was the totality of the territory of Mauritius before independence. That territory included the
Chagos Archipelago.”) with Chagos Marine Protected Area Arbitration (Mauritius v. United Kingdom)
[hereinafter Chagos Marine Arbitration], P.C.A. Case No. 2011-03 (Perm. Ct. Arb. 2015), Memorial of
Mauritius, para. 6.16 (“Thus, in the case of Mauritius, the unit of self-determination in relation to which the UK
as the administering power owed the duty to accord the right to self-determination was the whole of the territory
of Mauritius before independence, including the Chagos Archipelago.”); compare Mauritius Written Statement,
para. 6.68 (“[T]he General Assembly recognised the undivided territory of Mauritius as the unit of selfdetermination
in its Resolution 2066(XX) on the Question of Mauritius.”) with Chagos Marine Arbitration,
supra, Memorial of Mauritius, para. 6.20 (“The General Assembly recognised the undivided territory of
Mauritius as the unit of self-determination in its resolution 2066(XX) on the Question of Mauritius.”); compare
Mauritius Written Statement, para. 6.96(2) (“[T]he so-called ‘consent’ [to detachment] which was given was
extracted in circumstances of duress and on conditions that vitiated any notion that it was freely given”) with
Chagos Marine Arbitration, supra, Memorial of Mauritius, para. 6.29 (“It is clear that the ‘freely expressed will’
of the people of Mauritius was not obtained. The consent of the Mauritius Ministers was given in circumstances
which amounted to duress … .”).
18 Compare Mauritius Written Statement, para. 6.3(6) (stating that the pressure placed on Mauritian
representatives in 1965 “vitiated any purported consent on the part of the Mauritian people or their
representatives”) with United Kingdom Written Statement, paras. 8.13–8.15 (refuting arguments advanced by
Mauritius in the Chagos Marine Arbitration, in which Mauritius argued that it had not given valid consent to the
establishment of the BIOT) and para. 8.22 (stating that an “informed, free and voluntary choice was made by
Mauritius in 1965, 1967, and 1968”).
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2.9 The issue of consent to the establishment of the BIOT is of central importance
because, as Chapter III notes, many written statements acknowledged that the administrative
boundaries of a non-self-governing territory could be adjusted with the consent of the
people.19 Whether valid consent was given, either through the 1965 agreement or by virtue of
subsequent affirmations, is therefore directly relevant to the parties’ legal positions in their
territorial dispute.
2.10 At the same time, opining on the status of a bilateral agreement—especially when an
arbitral tribunal has already interpreted and applied it in contentious proceedings between the
parties—is the type of issue that is quintessentially unsuitable for the Court’s review in the
absence of mutual consent to the Court’s adjudication by the parties.20 That this issue lies at
the heart of the territorial sovereignty dispute reinforces the views conveyed in the written
statements of the United States and others that responding to the General Assembly’s request
would be “substantially equivalent to deciding the dispute between the parties.”21
B. The Court’s jurisprudence reaffirms the serious concerns inherent in rendering
an advisory opinion about a bilateral territorial dispute absent the consent of the
parties to the dispute.
2.11 Many States that addressed the Court’s discretion with respect to the exercise of its
advisory jurisdiction referenced the Court’s opinion in Western Sahara.22 The United States
agrees that the principles discussed in that case are centrally at issue here. However, a close
examination of Western Sahara shows that, rather than supporting a decision to respond as
some have suggested, the application of the Court’s approach in that case to the present
matter demonstrates that to give a reply would have the effect of circumventing the principle
of consent to judicial settlement.
2.12 Specifically, in reaching its decision in Western Sahara that giving an opinion would
not circumvent the principle of consent to judicial settlement, the Court relied on several key
elements that are notably absent here:
􀁸 First, the Court emphasized that responding to the General Assembly’s request would
“not affect the rights of Spain today as the administering Power …” and that “[i]t
19 See infra para. 3.49.
20 See infra paras. 2.18–2.21; East Timor (Portugal v. Australia), Judgment, I.C.J. Reports 1995, p. 90, para. 35
(concluding that it would be impermissible to adjudicate Portugal’s claims against Australia, which related to a
bilateral treaty between Australia and Indonesia, since doing so would require the Court to impermissibly rule
on the lawfulness of Indonesia’s conduct in the absence of its consent).
21 Status of Eastern Carelia, Advisory Opinion, 1923, P.C.I.J., Series B, No. 5 [hereinafter Eastern Carelia],
pp. 28–29. As the United States noted in footnote 38 of its Written Statement, although the Court has since
indicated that Eastern Carelia involved unique circumstances posed by Russia’s non-membership in the League
of Nations, that distinction does not undermine the continuing application of the principle as a constraint on the
Court’s advisory jurisdiction. See also infra paras. 2.14–2.15.
22 See, e.g., Australia Written Statement, para. 35; Chile Written Statement, para. 5; China Written Statement,
para. 16; Cyprus Written Statement, para. 27; France Written Statement, para. 7; Israel Written Statement, para.
2.2; Mauritius Written Statement, para. 5.26; Namibia Written Statement, p. 2; Russian Federation Written
Statement, para. 30; South Africa Written Statement, para. 42; United Kingdom Written Statement, para. 7.5.
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follows that the legal position of the State which has refused its consent to the present
proceedings is not ‘in any way compromised by the answers that the Court may give
to the questions put to it.’”23 The same cannot be said of the present request, which, if
answered in the way Mauritius proposes,24 could be seen as affecting the rights of the
United Kingdom today. As the United States explained in its Written Statement, it
would be difficult, if not impossible, for the Court to answer the questions posed
without appearing to compromise the legal positions of the parties to the underlying
bilateral territorial dispute.25
􀁸 Second, the Court in Western Sahara did not reject Spain’s contention that state
consent carries particular significance when a dispute concerns the attribution of
territorial sovereignty.26 Instead, the Court concluded that the absence of Spain’s
consent did not pose an obstacle to responding in that instance because “[t]he request
for an opinion [did] not call for the adjudication upon existing territorial rights or
sovereignty over territory.”27 In contrast, as Mauritius’s Written Statement makes
abundantly clear, Mauritius’s purpose in pursuing this request through the General
Assembly is to invite the Court to adjudicate its pending bilateral territorial dispute
with the United Kingdom, at the heart of which is whether Mauritius or the United
Kingdom possesses sovereignty over the Chagos Archipelago.28
􀁸 Third, the General Assembly requested the advisory opinion in Western Sahara at a
time when the Assembly (including the Fourth Committee and the Special Committee
on Decolonization) had been actively considering the situation in Western Sahara for
over a decade.29 The Court acknowledged the General Assembly’s long and
continuous involvement with Western Sahara in describing the resolution requesting
the advisory opinion—Resolution 3292 (XXIX)—as “the latest of a long series of
General Assembly resolutions dealing with Western Sahara.”30 The same cannot be
said of the dispute underlying the present request. It is notable in this regard that the
decolonization of Mauritius has not been debated by the General Assembly, its Fourth
Committee, or the Special Committee on Decolonization for decades. In fact, a new
23 Western Sahara, supra note 14, para. 42 (quoting Interpretation of Peace Treaties with Bulgaria, Hungary,
and Romania, Advisory Opinion (First Phase), I.C.J. Reports 1950, p. 65 [hereinafter Interpretation of Peace
Treaties], p. 72).
24 See Mauritius Written Statement, p. 285.
25 United States Written Statement, paras. 2.16, 3.30, 5.3.
26 Western Sahara, supra note 14, para. 43.
27 Id.
28 See Mauritius Written Statement, p. 285 (submitting that “international law requires that … the process of
decolonisation of Mauritius be completed immediately, including by the termination of the administration by the
United Kingdom of Great Britain and Northern Ireland of the Chagos Archipelago, so that Mauritius is able to
exercise sovereignty over the totality of its territory”); see also United States Written Statement, paras. 3.25–
3.28.
29 See Western Sahara, Written Statements and Documents, Volume I (1979), paras. 11–55, available at
http://www.icj-cij.org/files/case-related/61/9467.pdf.
30 Western Sahara, supra note 14, para. 53.
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item had to be added to the General Assembly’s agenda in order for it to consider the
present request.31
􀁸 Fourth, in deciding that it could take up the case, the Court noted in Western Sahara
that “the object of the General Assembly ha[d] not been to bring before the Court, by
way of request for advisory opinion, a dispute or legal controversy in order that it may
later, on the basis of the Court’s opinion, exercise its powers and functions for the
peaceful settlement of that dispute or controversy.”32 Here, in contrast, the object of
the General Assembly’s request—particularly when read in light of Mauritius’s
Written Statement—is precisely to seek the Court’s involvement in the longstanding
territorial sovereignty dispute as a means of advancing new efforts in the General
Assembly or elsewhere to exert pressure on the United Kingdom to enable Mauritius
to exercise immediate sovereignty over the Chagos Archipelago.33
2.13 Similarly, in contrast to the views expressed by some States,34 the Court’s decision in
Construction of a Wall does not lend support to arguments that the Court could, consistent
with its judicial function, respond to the General Assembly’s request here. There, the Court
acknowledged that “the question of the wall is part of a greater whole”35 and decided it could
respond without circumventing the consent principle because the question was “located in a
much broader frame of reference than a bilateral dispute.”36 In contrast, as discussed in
Section A above, the submissions here demonstrate that the questions referred go to the crux
of the underlying bilateral sovereignty dispute, and it is difficult to see how the Court could
answer the General Assembly’s request without appearing to decide the dispute between the
parties.
2.14 Furthermore, the effort by some States in their written statements to diminish the
relevance of the Permanent Court of International Justice’s advisory opinion in Eastern
Carelia misses the point. Those submissions argue that Eastern Carelia hinged solely on the
fact that Russia was not a member of the League of Nations at the time.37 But, as the decision
demonstrates, the Permanent Court’s rationale was not so limited, and in fact clearly applies
to pending disputes presented to this Court under the guise of a request for an advisory
opinion. As the Permanent Court explained:
The question put to the Court is not one of abstract law, but concerns directly the
main point of controversy between Finland and Russia, and can only be decided by an
31 Request for the Inclusion of an Item in the Provisional Agenda of the Seventy-First session, Request for an
Advisory Opinion of the International Court of Justice on the Legal Consequences of the Separation of the
Chagos Archipelago from Mauritius in 1965, Letter Dated 14 July 2016 from the Permanent Representative of
Mauritius to the United Nations Addressed to the Secretary-General, U.N. Doc. A/71/142 (July 14, 2016).
32 Western Sahara, supra note 14, para. 39.
33 See Mauritius Written Statement, p. 285.
34 See, e.g., Djibouti Written Statement, para. 22; Guatemala Written Statement, para. 26; South Africa Written
Statement, para. 35.
35 Construction of a Wall, supra note 12, para. 54.
36 Id., para. 50.
37 See, e.g., Brazil Written Statement, para. 10 (arguing that the Eastern Carelia “finds no possible application
here, since all States that might be concerned are parties to the Charter and to the Statute”).
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investigation into the facts underlying the case. Answering the question would be
substantially equivalent to deciding the dispute between the parties. The Court, being
a Court of Justice, cannot, even in giving advisory opinions, depart from the essential
rules guiding their activity as a Court.38
2.15 This Court’s application of this same analysis in Interpretation of Peace Treaties
confirms the relevance of Eastern Carelia. There the Court did not dispense with the
Permanent Court’s reasoning in Eastern Carelia, but instead concluded that rendering an
advisory opinion would not be impermissible precisely because the request “in no way
touch[ed] the merits of [the underlying] disputes” and “[i]t follow[ed] that the legal position
of the parties to these disputes [could not] be in any way compromised by the answers that
the Court may give to the Questions put to it.”39
2.16 In conclusion, none of the Court’s prior advisory opinions can be read to suggest that
the Court should respond to an advisory opinion request if doing so would be tantamount to
adjudicating a bilateral territorial dispute, or would compromise the legal positions of the
parties to that dispute. To the contrary, the Court’s jurisprudence confirms that to give a reply
in these circumstances would have the impermissible effect of circumventing the
fundamental principle of consent to judicial settlement.
C. No other factor identified justifies dispensing with the serious concerns of
judicial propriety implicated by this request.
2.17 A number of written statements argued that the existence of a bilateral dispute should
not prevent the Court from responding to the General Assembly’s request.40 In support of this
argument, several written statements noted the dispute could not be regarded as purely
bilateral due either to: (1) the erga omnes character of self-determination;41 or (2) the General
Assembly’s purported interest in the bilateral dispute over the status of the Chagos
Archipelago.42 Neither of these factors, nor any others presented in the written statements,
justifies dispensing with the serious concerns of judicial propriety that the General
Assembly’s request presents.
1. Despite the erga omnes character of self-determination, the principle of
non-circumvention of consent still applies.
2.18 To support their contention that the questions referred go beyond the pending bilateral
dispute, some States in their written statements cite to the 1995 judgment in East Timor, in
which the Court characterized self-determination as giving rise to obligations erga omnes.43
The implication of this argument appears to be that the principle of consent to judicial
38 Eastern Carelia, supra note 21, pp. 28–29.
39 Interpretation of Peace Treaties, supra note 23, p. 72.
40 See, e.g., Liechtenstein Written Statement, para. 16; Marshall Islands Written Statement, para. 15; Serbia
Written Statement, para. 25.
41 See, e.g., Djibouti Written Statement, para. 22; Mauritius Written Statement, para. 5.31.
42 See, e.g., African Union Written Statement, para. 62; Mauritius Written Statement, para. 1.15.
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settlement is somehow less relevant to the question of judicial propriety if the request for an
advisory opinion might implicate obligations that are of concern to members of the
international community other than the parties to the dispute.
2.19 This reading of East Timor is incorrect. Rather, the Court in that case held that
consent to judicial settlement remains a critical requirement even where erga omnes
obligations may be involved:
[T]he erga omnes character of a norm and the rule of consent to jurisdiction are two
different things. Whatever the nature of the obligations invoked, the Court could not
rule on the lawfulness of the conduct of a State when its judgment would imply an
evaluation of the lawfulness of the conduct of another State which is not a party to the
case. Where this is so, the Court cannot act, even if the right in question is a right erga
omnes.44
2.20 Portugal had argued in that case that it should be permitted to challenge a treaty
between Australia and Indonesia concerning East Timor, in part because self-determination
related to obligations erga omnes. Although the Court agreed that self-determination had by
that point achieved an erga omnes character, it held that it could not adjudicate the issue
because it “would necessarily have to rule upon the lawfulness of Indonesia’s conduct”—
which was not a party to those proceedings—in a manner that “would run directly counter to
the ‘well-established principle of international law embodied in the Court’s Statute, namely,
that the Court can only exercise jurisdiction over a State with its consent.’”45
2.21 This decision highlights that the substantive basis for a State’s claim—even where the
claim may rest on an alleged violation of an obligation erga omnes—is conceptually distinct
from whether the Court can or should address a bilateral dispute absent the consent of a party
to that dispute.46 Therefore, although Mauritius asserts that it has a superior claim to the
Chagos Archipelago because the decolonization of Mauritius allegedly did not conform to
purported legal obligations arising from self-determination that had an erga omnes character,
the consent principle remains an essential element in determining whether it would be
appropriate for the Court to adjudicate a bilateral dispute. The asserted erga omnes character
of obligations simply does not bear on this question. And where the very validity of a
bilateral agreement is in dispute—in this case as it was in East Timor—it would be
particularly inappropriate for the Court to act in the absence of the consent of both parties to
the agreement.
43 See, e.g., Djibouti Written Statement, para. 22.
44 East Timor, supra note 20, para. 29. The Court held in Armed Activities on the Territory of the Congo that
“[t]he same applies to the relationship between peremptory norms of general international law (jus cogens) and
the establishment of the Court’s jurisdiction: the fact that a dispute relates to compliance with a norm having
such a character … cannot of itself provide a basis for the jurisdiction of the Court to entertain that dispute.
Under the Court’s Statute that jurisdiction is always based on the consent of the parties.” Armed Activities on the
Territory of the Congo (New Application: 2002) (Democratic Republic of the Congo v. Rwanda), Jurisdiction
and Admissibility, Judgment, I.C.J. Reports 2006, p. 6, para. 64.
45 East Timor, supra note 20, paras. 33–35 (citing Case of the Monetary Gold Removed from Rome in 1943,
Preliminary Question, Judgment, I.C.J. Reports 1954, p. 19, 32).
46 See also CHRISTIAN TAMS, ENFORCING OBLIGATIONS ERGA OMNES IN INTERNATIONAL LAW 166 (2005).
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2. The General Assembly’s purported interest in the bilateral dispute over the
status of the Chagos Archipelago does not dispense with the principle of
non-circumvention of consent.
2.22 In their written statements, many States noted the General Assembly’s historic interest
and active participation in promoting the decolonization process.47 These submissions,
however, did not agree on the propriety of the Court responding to the present request.
2.23 Several States, including the United States, pointed out that, in fact, the General
Assembly had not addressed the decolonization of Mauritius or issues associated with the
Chagos Archipelago for many decades.48 As noted above, a new agenda item had to be
created for the referral resolution to be considered.49
2.24 As a result, this is not a case where the requesting body has had a topic under active
consideration and seeks the Court’s advice through the advisory opinion procedure. Rather, it
is a situation in which proponents of the referral are arguing for the Court to set aside its
longstanding jurisprudence on non-circumvention of consent because of potential future
consideration by the General Assembly.
2.25 But if such an approach were adopted, it would mean that a party to any bilateral
dispute could have its dispute adjudicated through the advisory opinion procedure simply by
recasting the claim as a matter that could be addressed by the General Assembly. This would
severely undermine the non-circumvention principle, given the General Assembly’s broad
mandate. The Court has never suggested that the non-circumvention principle somehow loses
its centrality because the General Assembly, despite having had no direct engagement on the
matter for many decades, might add the matter to its agenda in the future.
2.26 Several States—including those that did not take a position on the merits of the
dispute—emphasized the importance of upholding the consent principle even if the Court
should decide to respond to the General Assembly’s request. China, for example, stated that
“[w]hile providing legal guidance to assist the General Assembly in fulfilling its function of
decolonization, the Court should continue to uphold and respect the principle of consent
when a purely bilateral dispute is involved, thus to ensure that its opinion should not have the
effect of circumventing or prejudicing this principle.”50 Chile, while stating its support for the
decolonization of Mauritius, also cautioned that “matters of a purely bilateral nature between
47 See, e.g., China Written Statement, para. 5 (“Decolonization has been an important function of the United
Nations.”); Cyprus Written Statement, para. 3 (recognizing the “critical role of the General Assembly in the
decolonization process”); Germany Written Statement, para. 45 (noting that decolonization is “an issue that has
been at the heart of the work of the [United Nations] ever since its inception”); India Written Statement, para. 27
(referring to the United Nations as “the chief world body to help achieve the object of decolonization”); Russian
Federation Written Statement, paras. 23–25 (noting the General Assembly’s institutional interest in the
decolonization process).
48 See, e.g., Australia Written Statement, para. 54 (noting that, in contrast to prior requests for advisory opinions,
“neither the Security Council nor the General Assembly have been actively considering matters relating to the
Chagos Archipelago (whether in the context of decolonization or otherwise)”); United States Written Statement,
para. 3.23.
49 See supra text accompanying note 31.
50 China Written Statement, para. 18.
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two sovereign states[] should be handled by the appropriate means reflecting the consent of
the interested parties.”51 Germany, for its part, stated that:
[C]ertain aspects of the questions submitted to the Court, if too broadly interpreted,
may touch upon issues that concern only the two States involved, namely Mauritius
and the United Kingdom, or possibly third States. Bearing this in mind, Germany is of
the opinion that a request for an advisory opinion ought not to be interpreted in a
manner that would circumvent the fundamental principle that the Court’s jurisdiction
is based upon the consent of both States.52
2.27 These statements seem to contemplate—or at least do not appear to rule out the
possibility—that the Court could somehow respond to the request without impermissibly
adjudicating the bilateral territorial dispute between Mauritius and the United Kingdom.
However, they do not provide substantive detail on how the Court might limit its advisory
opinion to discrete non-bilateral aspects of the request that are of relevance to the General
Assembly’s functions related to decolonization.
2.28 Indeed, it is difficult to see how the purely bilateral matters at the heart of this
request—in particular the dispute concerning the status of the 1965 agreement and related
matters—could be isolated from any discussion of whether the process of decolonization of
Mauritius was “lawfully completed” in 1968 or from the possible legal consequences for
Mauritius and the United Kingdom arising out of the current status of the Chagos
Archipelago. Moreover, when read in light of Mauritius’s submission, it is plain that the
request is improperly designed “to bring before the Court, by way of a request for advisory
opinion, a dispute or legal controversy, in order that it may later, on the basis of the Court’s
opinion, exercise its powers and functions for the peaceful settlement of that dispute or
controversy.”53
2.29 While the United States acknowledges the importance of the Court’s advisory
function, and in particular its ability “to guide the United Nations in respect of its own
action,”54 the advisory function does not empower the Court to disregard its duty to uphold
the consent-based system of dispute settlement on which its jurisdiction is based.
Accordingly, unless the Court can avoid addressing the bilateral issues in dispute between
Mauritius and the United Kingdom, it should decline to issue an advisory opinion.
51 Chile Written Statement, para. 9.
52 Germany Written Statement, para. 151.
53 Western Sahara, supra note 14, para. 39 (suggesting this would be an improper purpose for seeking an
advisory opinion from the Court).
54 Id., para. 41 (quoting Reservations to the Convention on Genocide, Advisory Opinion, I.C.J. Reports 1951,
p. 15, 19).
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D. The principle of consent commands particular respect when the request relates
to a dispute involving sovereignty over territory.
2.30 The United States was one of several States to point out in its Written Statement that
where a dispute involves sovereignty over territory, the principle of consent commands
particular respect.55 Although these States addressed the issue in different ways, all
highlighted the need for increased scrutiny where matters of territorial sovereignty are
concerned.
2.31 The Republic of Korea, for example, noted that an advisory opinion directly related to
the main point of a territorial sovereignty dispute “would be substantially equivalent to
deciding the dispute between the parties” since disputes of this kind are “unsuitable to be
determined by a majority vote at a political body such as the General Assembly.”56 This
situation, the Republic of Korea argues, would present a compelling reason to decline to give
an opinion.57
2.32 The Russian Federation, for its part, noted that when a request for an advisory opinion
“transmits to the Court not just a dispute but a bilateral territorial dispute[,] the criterion [for
exercising advisory jurisdiction] must be even higher.”58 The United States raised a similar
point in its Written Statement in the context of the Court’s exercise of its discretion,59 and
continues to consider the territorial nature of this dispute as a factor that the Court should
weigh heavily when considering whether rendering a response would be compatible with the
proper exercise of its judicial function.
* * *
2.33 In light of the above and the views expressed in its Written Statement, the United
States remains of the view that the Court should decline to respond to the General
Assembly’s request in order to avoid impermissibly adjudicating a dispute in the absence of
the parties’ consent. The United States continues to view the present request for an advisory
opinion as an effort to circumvent the fundamental principle of consent to judicial settlement
in what is—and which for decades has been understood as—a bilateral dispute between
States concerning sovereignty over territory.
2.34 In accordance with the Court’s jurisprudence and in order to protect the integrity of its
judicial function, the United States therefore reiterates its request to the Court not to exercise
jurisdiction over this matter.
55 See Israel Written Statement, paras. 3.17–3.20; Republic of Korea Written Statement, paras. 23–24, Russian
Federation Written Statement, paras. 29–32; United States Written Statement, paras. 3.29–3.31.
56 Id.
57 Id.
58 Russian Federation Written Statement, para. 32 (emphasis added).
59 United States Written Statement, paras. 3.29–3.31.
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CHAPTER III
CONSIDERATIONS RELATING TO THEQUESTIONS REFERRED
3.1 In this Chapter, the United States offers some observations on those written
statements that address the merits of the questions in the referral. The United States will focus
primarily on the argument that a new rule of customary international law had emerged by
1965, or 1968 at the latest, that prohibited the United Kingdom from establishing the BIOT
prior to Mauritius’s independence. The Court would, of course, only need to examine such
arguments if it determined that it can offer an opinion on the questions referred without
contravening the principle of consent to judicial settlement.
3.2 The majority of written statements either did not address, or did not address in any
detail, how the Court should answer the questions referred. In some cases, this was because
the State believed it inappropriate for the Court to reach the questions, or suggested that the
Court exercise caution if it were to do so.60 In other cases, it was because the submissions
were brief or consisted primarily of an expression of general support for Mauritius’s position.
But in those statements that did provide substantive observations on the questions referred, a
few key points of agreement emerge.
3.3 These written statements appear to have conceded that the relevant law is the law
applicable at the time—1965, or 1968 at the latest—and not the law as it may later have
developed.61 The statements also generally focused on whether a relevant rule of customary
international law emerged in this period, as opposed to whether there was applicable treaty
law. In addition, although only a few statements specifically discussed changes to territorial
boundaries, those that did generally agreed that boundaries could be changed with the free
consent of the people of the territory.
3.4 The written statements diverged on how the Court might answer Question (a). Of the
statements that asserted that the decolonization of Mauritius was either not completed or was
unlawfully completed, three issues merit attention and will be addressed in this Chapter.
3.5 Section A explains how the Court would need to assess whether a specific rule of
customary international law existed at the relevant time. Most of the statements either did not
describe in detail how the Court should ascertain that law, or did not rely on the methodology
set out in the Court’s Statute and jurisprudence. In this section, the United States will thus
recall the Court’s jurisprudence on the sources of international law, including what is
required to establish the existence of a rule under customary international law—both state
60 See, e.g., Australia Written Statement, paras. 3–6; Chile Written Statement, paras. 4–5; China Written
Statement, paras. 14–18; France Written Statement, paras. 4–19; Germany Written Statement, paras. 17, 30–48;
Israel Written Statement, paras. 1.2–1.5; Russian Federation Written Statement, paras. 29–35.
61 See, e.g., African Union Written Statement, para. 70. On this “intertemporal” rule, see, e.g., South West
Africa, Second Phase, Judgment, I.C.J. Reports 1966, p. 6, para. 16. As the United States explained in its
Written Statement, and contrary to what the African Union has suggested, see, e.g., African Union Written
Statement, para. 71, it is for the Court—not the General Assembly in its referral resolution—to determine the
applicable law. See United States Written Statement, para. 4.14 (citing Accordance with International Law of
the Unilateral Declaration of Independence in Respect of Kosovo, Advisory Opinion, I.C.J. Reports 2010, p. 403
[hereinafter Kosovo], para. 52).
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practice and opinio juris—and the significance of General Assembly resolutions in
ascertaining opinio juris.
3.6 Section B responds to several statements that argued that a right of self-determination
had emerged in customary international law by 1965 (or 1968). A smaller number of
statements asserted that this right imposed an obligation on the administering State to
maintain the boundaries of the territory as they existed at some point prior to independence.
3.7 In addressing these arguments, the United States evaluates the nature of the sources
that were cited by States as evidence that a relevant rule of customary international law had
emerged by 1965 (or 1968), including: (1) General Assembly resolutions from the 1950s and
1960s, particularly Resolution 1514 (XV); (2) U.N. Security Council resolutions from the
1960s that referenced Resolution 1514; (3) the number of States that gained independence in
the 1950s and 1960s; and (4) works by certain publicists regarding the state of international
law in the 1960s.
3.8 As explained below, these sources fail to support the establishment of a relevant legal
obligation. Even if one could conclude from the relevant sources that there was growing
consensus around the existence of a right of self-determination in international law in the late
1960s, there was manifestly no consensus on specific obligations on administering States,
much less consensus on an obligation to maintain territorial boundaries.
3.9 Section C addresses the few statements that acknowledged that territorial boundaries
could be changed with the free consent of the people, but suggested that consent could only
be ascertained through a plebiscite. This section explains that there was no legal obligation on
administering States to hold a plebiscite to determine the freely expressed wishes of the
people of a territory.
3.10 As the United States explained in its Written Statement, and will detail further in this
Chapter, the historical, legally relevant materials do not support a claim that a new legal
obligation had emerged at the relevant time that would have prohibited establishment of the
BIOT. The answer to Question (a) is therefore that the decolonization of Mauritius was
lawfully completed, obviating the need to answer Question (b).
A. The Court would need to examine the historical record through the lens of the
established sources of international law, as set forth in its Statute and elaborated
in its jurisprudence.
3.11 As the United States explained in its Written Statement, the Court would need to look
to one (or both) of two sources of law under Article 38 of its Statute in order to ascertain the
state of international law at the time the BIOT was established: (1) treaty law and
(2) customary international law.62
3.12 For the reasons described in the U.S. Written Statement, the text and negotiating
history of the U.N. Charter lend no support to the idea that the Charter contained
62 United States Written Statement, para. 4.24.
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requirements for an administering State to ascertain the wishes of the people of a non-selfgoverning
territory as to the territory’s ultimate political status or before making adjustments
to administrative boundaries.63 The only other potentially relevant multilateral treaties are the
Human Rights Covenants, which did not come into force until a decade after the period in
question.64
3.13 In the absence of a relevant treaty provision, any applicable rule of international law
would thus need to have existed in customary international law.65 The Court explained the
two components of customary international law—both of which must be met—in North Sea
Continental Shelf: (1) State conduct that “amount[ed] to a settled practice,” that was
(2) “carried out in such a way, as to be evidence of a belief that this practice is rendered
obligatory by the existence of a rule of law requiring it [i.e., opinio juris].”66 The Court
clarified that the practice must have occurred “within the period in question”; “been both
extensive and virtually uniform”; and “occurred in such a way as to show a general
recognition that a rule of law or legal obligation is involved.”67
3.14 Several written statements point to General Assembly resolutions on decolonization
from the 1950s and 1960s and make a variety of different arguments about their relevance to
determining the existence of a specific rule of customary international law, with some simply
assuming that the resolutions set forth binding rules of international law.68 But General
63 United States Written Statement, paras. 4.26, 4.33–4.34. Other States’ written statements also set forth this
view. See, e.g., South Africa Written Statement, para. 62; Netherlands Written Statement, paras. 3.1–3.2
(distinguishing the law under the Charter from the General Assembly’s evolving policy in favor of
independence for dependent territories). See also ROSALYN HIGGINS, PROBLEMS AND PROCESS: INTERNATIONAL
LAW AND HOW WE USE IT 111 (1994) (stating that in 1946, the duties of administering States “did not clearly
include any duty to grant independence” and “[t]he common assumption that the UN Charter underwrites selfdetermination
in the current sense of the term is in fact a retrospective rewriting of history”).
Several written statements argue that it is legally significant that the French-language version of the
Charter uses the word “droit” in Articles 1(2) and 55, in referring to the “principe de l’égalité de droits des
peuples et de leur droit à disposer d’eux-mêmes.” African Union Written Statement, para. 81; Belize Written
Statement, para. 2.3; Brazil Written Statement, para. 16; Djibouti Written Statement, para. 28; Mauritius Written
Statement, para. 6.22. However, under Article 111 of the U.N. Charter, the Chinese, Russian, English, and
Spanish texts are as authentic as the French text, yet none of those other texts uses the respective language’s
word for “right” with respect to self-determination. It seems especially difficult to conclude that the Charter
established a legal right of self-determination, even discounting the absence of evidence of any such intention in
the negotiating history, when “right” does not appear in four of the five equally authentic texts. See Vienna
Convention on the Law of Treaties, May 23, 1969, 1155 U.N.T.S. 331, art. 33(3) (“The terms of [a treaty
authenticated in two or more languages] are presumed to have the same meaning in each authentic text.”); id.,
art. 33(4) (“[W]hen a comparison of the authentic texts discloses a difference of meaning which the application
of articles 31 and 32 [of this treaty] does not remove, the meaning which best reconciles the texts, having regard
to the object and purpose of the treaty, shall be adopted.”).
64 See United States Written Statement, para. 4.26.
65 None of the written statements suggests that the principle of self-determination constitutes a general principle
of law, as set forth in Article 38(1)(c) and as interpreted by the Court, nor does the United States believe that
source of law is relevant here.
66 North Sea Continental Shelf, Judgment, I.C.J. Reports 1969, p. 3 [hereinafter North Sea Continental Shelf],
para. 77 (emphasis added).
67 Id., para. 74.
68 See, e.g., Argentina Written Statement, paras. 48–49; Cuba Written Statement, p. 2 (United Kingdom failed to
comply with “obligations contained in” several General Assembly resolutions); Djibouti Written Statement,
para. 33 (arguing that repeated references to a “right” of self-determination in a series of resolutions meant that a
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Assembly resolutions, even those styled as “declarations,” are not themselves legally binding,
except in rare circumstances not relevant here.69 Such resolutions could only be relevant to
this Court’s inquiry to the extent they reflect opinio juris that was accompanied by the
extensive and virtually uniform practice of States.70
3.15 In determining whether a particular General Assembly resolution provides “evidence
important for establishing the existence of a rule or the emergence of an opinio juris,”
the Court has stressed that “it is necessary to look at its content and the conditions of its
adoption.”71 The Court has further emphasized that deducing opinio juris from “the attitude
of States toward certain General Assembly resolutions” must be done “with all due
caution.”72 Statements made by States during negotiation of a particular resolution and before
legal right “had already crystalized before” 1965); Guatemala Written Statement, para. 34; India Written
Statement, para. 62 (referring to U.K. actions allegedly “in violation of obligations under” Resolution 1514, and
asserting that Resolution 2066 (XX) “obligated the UK to complete the decolonization of Mauritius”).
69 See U.N. Charter, arts. 10, 11, 13, 14 (General Assembly’s recommendatory powers). See also, e.g., Letter
from the U.N. Office of Legal Affairs to the Permanent Observer of an Intergovernmental Organization to the
United Nations (May 9, 1986), in 1986 U.N. Jurid. Y.B. 274, 275, U.N. Doc. ST/LEG/SER.C/28 (General
Assembly resolutions “other than those relating to the institutional framework and administrative and financial
administration of the Organization are recommendatory in nature and are thus not legally binding even on those
Members that vote in favour of the resolutions.”).
70 North Sea Continental Shelf, supra note 66, para. 77. Accord, e.g., Robert Rosenstock, U.S. Representative,
Address Before the U.N. General Assembly Sixth Committee (Legal) (Nov. 11, 1977), in DIGEST OF UNITED
STATES PRACTICE IN INTERNATIONAL LAW 1977 53, 54 (John A. Boyd ed., 1979) (“[A] General Assembly
resolution may contribute to the development of international law … only if the resolution gains virtually
universal support, if the Members of the General Assembly share a lawmaking or law-declaring intent—and if
the content of that resolution is reflected in general state practice.” (emphasis added)); U.N. Doc.
A/C.6/32/SR.44 (Nov. 15, 1977), para. 19 (portion of Nov. 11, 1977 record summarizing Rosenstock’s address);
Letter from Stephen M. Schwebel, Deputy Legal Adviser, U.S. Department of State, to Marcus G. Raskin, Co-
Director, Institute for Policy Studies (Apr. 25, 1975), in DIGEST OF UNITED STATES PRACTICE IN
INTERNATIONAL LAW 1975 85, 85 (Eleanor C. McDowell ed., 1976) (“To the extent, which is exceptional, that
General Assembly resolutions are meant to be declaratory of international law, are adopted with the support of
all members, and are observed by the practice of States, such resolutions are evidence of customary
international law on a particular subject matter.” (emphasis added)); S. Prakash Sinha, Self-Determination in
International Law and Its Application to the Baltic Peoples, in RES BALTICA: ACOLLECTION OF ESSAYS IN
HONOR OF THE MEMORY OF DR. ALFRED BILMANIS 256, 266 (Adolf Sprudzs & Armins Rusis eds., 1968)
(“[E]ven if it is accepted that the specific norms asserted in the political organs [of the United Nations] may be
legally authoritative on the basis of their acceptance and validity as interpretation[s] of the Charter … it is
necessary that they influence actual behavior in order to secure an obligatory character which is more than
nominal.” (internal quotation marks omitted)).
It would not be enough, as the African Union argues, that the resolution in question enjoyed “near
unanimous” support of Member States or even if the General Assembly “meant to establish a customary
international law principle.” African Union Written Statement, para. 76. These considerations cannot serve as a
substitute for actual state practice undertaken out of a belief that the law requires it. See, e.g., Report of the
International Law Commission, 68th Sess., U.N. Doc. A/71/10 (2016), ch. V: “Identification of Customary
International Law” [hereinafter ILC 2016 Conclusions on Customary International Law], p. 107, para. 4. While
the United States has concerns about aspects of these draft conclusions, see Comments from the United States
on the International Law Commission’s Draft Conclusions on the Identification of Customary International Law
as Adopted by the Commission in 2016 on First Reading, Jan. 5, 2018 [hereinafter U.S. 2018 ILC Comments],
available at http://www.ejiltalk.org/wp-content/uploads/2019/02/US-Views-on-ILC-Draf…-
CIL.pdf, it believes they properly describe many aspects of how customary international law is ascertained.
71 Legality of the Threat or Use of Nuclear Weapons, Advisory Opinion, I.C.J. Reports 1996, p. 226 [hereinafter
Nuclear Weapons], para. 70.
72 Military and Paramilitary Activities in and Against Nicaragua (Nicaragua v. United States of America),
Merits, Judgment, I.C.J. Reports 1986, p. 14, para. 188.
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or after its adoption provide key evidence of those States’ contemporaneous attitude toward
the resolution or the state of international law at the time.73
B. The sources cited by the written statements asserting that a rule of customary
international law had emerged do not support that conclusion.
1. General Assembly resolutions from the 1950s and 1960s, including
Resolution 1514, did not establish or reflect a relevant rule of customary
international law.
3.16 Several written statements argued that certain General Assembly resolutions from the
1960s, or particular provisions thereof, reflected customary international law already in
existence at the time of their adoption,74 or that the resolutions themselves created customary
international law.75 Without question, nearly all States in this period voiced strong moral and
political support for the principle of self-determination and praised its influential role in the
postwar wave of decolonization.76 Yet indications of moral and political support are not
enough to establish opinio juris. Instead, States must believe that international law requires
the conduct in question.
3.17 In this regard, as the United States explained in its Written Statement,77 a significant
group of States did not, at that time, accept that self-determination had become a rule of
international law. States also disagreed sharply about the definition and scope of selfdetermination
during the negotiations of Resolution 1514 and other decolonization
resolutions.
3.18 The written statements arguing for the existence of a rule of customary international
law by the early-to-mid 1960s also failed to take account of evidence demonstrating that this
lack of agreement continued through the end of the 1960s. For example, one day after it
adopted Resolution 1514, the General Assembly adopted Resolution 1541 (XV), which
contains some provisions that are materially at odds with Resolution 1514.78 Negotiations
surrounding the creation of the Special Committee on Decolonization the following year
likewise reveal persistent disagreement about key elements of Resolution 1514.79
73 See ILC 2016 Conclusions on Customary International Law, supra note 70, p. 108, para. 6.
74 See, e.g., African Union Written Statement, para. 77; Belize Written Statement, paras. 2.5–2.15; Mauritius
Written Statement, paras. 6.23–6.33; Netherlands Written Statement, paras. 3.7–3.8.
75 African Union Written Statement, para. 76.
76 See, e.g., infra text accompanying notes 116–117.
77 See United States Written Statement, paras. 4.35–4.60.
78 See id., para. 4.52 (explaining differences such as Resolution 1541’s various options available to the people of
a territory, as contrasted with Resolution 1514’s focus on independence).
79 For example, in the context of the General Assembly’s adoption of Resolution 1654 (XVI), which created the
Special Committee, several States emphasized that an “immediate” grant of independence would not be
appropriate in all circumstances, and that the particular situation of each territory should be considered. See
United States Written Statement, para. 4.53 n. 148. States also rejected a Soviet amendment to Resolution 1654
that would have identified 1962 as the year of elimination of colonialism. U.N. Doc. A/PV.1066 (Nov. 27,
1961), paras. 59–71 (Soviet delegate explaining amendment); id., para. 147 (amendment rejected on a vote of
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3.19 Perhaps the best evidence of the continued lack of consensus, however, is found in the
negotiating records of the Friendly Relations Declaration, which States negotiated from the
mid-1960s to 1970. When States initially gathered in 1962 to formulate a list of U.N. Charter
principles to elaborate in the Friendly Relations Declaration, some asserted that selfdetermination
was already part of international law.80 Others, such as Thailand, took the
opposite position: “Th[e] principle [of self-determination], despite the efforts made by the
Organization [of the United Nations], was still a long way from having become a principle of
international law.”81
3.20 In further discussions about the Friendly Relations Declaration in 1965, States
continued to disagree about whether self-determination constituted a legal right.82
3.21 The States that were members of the Special Committee established to draft the
Friendly Relations Declaration continued to debate self-determination on the record through
five annual sessions from 1966 to 1970. A number of States asserted that self-determination
was a norm of international law.83 By contrast, a significant number of States maintained that
the principle of self-determination was not yet a right under international law, or even if it did
form part of international law, the elements of such a right or any corresponding obligations
had yet to be defined.84
46–19–36); see also, e.g., id., para. 137 (El Salvador: “It may perhaps be going too far to want 1962 to be
proclaimed the year of the elimination of colonialism … because it is an undeniable fact that not all the peoples
of these territories are yet in a position to attain full self-government, and still less full independence.”).
80 See, e.g., U.N. Doc. A/C.6/SR.769 (Nov. 29, 1962), para. 34 (Yugoslavia: “General Assembly had settled …
once and for all by its Resolution 1514” “whether the principle of self-determination … was a legal principle.”);
U.N. Doc. A/C.6/SR.766 (Nov. 28, 1962), para. 8 (Cyprus stating that self-determination “might be fairly called
[an] established norm[] of international law”); U.N. Doc. A/C.6/SR.765 (Nov. 23, 1962), para. 4 (Tunisia:
“Since 1945, the principle of self-determination … had evolved into an obligation, incumbent upon all colonial
countries, to free the populations still under their administration.”).
81 U.N. Doc. A/C.6/SR.763 (Nov. 20, 1962), para. 12. Accord, e.g., U.N. Doc. A/C.6/SR.769, supra note 80,
para. 3 (United Kingdom: “[T]he right to self-determination … was questionable and was not recognized
anywhere in the Charter.”); U.N. Doc. A/C.6/SR.759 (Nov. 14, 1962), para. 21 (Sweden stressing that, even
though the principle of self-determination was “fundamentally important,” “it would be extremely difficult, if
not impossible, to define that principle in precise legal terms”).
82 See, e.g., U.N. Doc. A/C.6/SR.891 (Dec. 6, 1965), para. 37 (Ceylon noting the persistence of “much
disagreement on whether there was a legal right to self-determination or whether the provisions of the Charter
were merely an expression of hope with no legal substance”); id., para. 13 (France: “[T]he question arose … in
respect of the principle of self-determination … whether [it] constituted, and had constituted ever since the
adoption of the Charter, a positive rule of international law, or whether it was simply a question of a
philosophical or political rule or a precept of international morality.”).
83 See, e.g., U.N. Doc. A/AC.125/SR.92 (Oct. 21, 1968) (negotiations of Sept. 24, 1968), p. 122 (Madagascar);
U.N. Doc. A/AC.125/SR.68 (Dec. 4, 1967) (negotiations of Aug. 3, 1967), p. 17 (Ghana); U.N. Doc.
A/AC.125/SR.41 (July 27, 1966) (negotiations of Apr. 11, 1966), para. 3 (Kenya); U.N. Doc. A/AC.125/SR.40
(July 27, 1966) (negotiations of Apr. 7, 1966), para. 2 (Czechoslovakia); id., para. 17 (Yugoslavia).
84 See, e.g., U.N. Doc. A/AC.125/SR.93 (Oct. 21, 1968) (negotiations of Sept. 25, 1968), pp. 145–46 (Canada
noting “there were serious differences of opinion on the interpretation of self-determination,” and thus the “aim”
of the Special Committee’s work on self-determination “must be to define the legal components of the principle,
and, if possible lay down some guidelines as to the situations to which the formulation was to apply” (quotations
respectively at pp. 145, 146)); U.N. Doc. A/AC.125/SR.92, supra note 83, p. 121 (United Kingdom: “[T]he
United Kingdom had always believed that, in so far as self-determination was a legal, and not merely a political
concept, it was properly expressed as a principle and not a right. However, … [it] was prepared … to participate
in attempts to formulate the principle of self-determination in terms of a ‘right.’”); U.N. Doc. A/AC.125/SR.70
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3.22 It was widely understood that the members of the Special Committee were at odds
over self-determination. As Venezuela observed in 1967,“[t]here appeared to be no
agreement even on the question whether equal rights and self-determination of peoples
constituted a recognized and universal principle of contemporary international law,” or on the
principle’s possible elements, scope, or practical effects.85
3.23 States involved in the Friendly Relations Declaration negotiations also disagreed over
whether Resolution 1514 could be regarded as reflecting international law. As the Special
Committee noted in 1967, some delegations stated that General Assembly resolutions “should
not be regarded as having a legally binding effect on the Special Committee in its formulation
of the legal content of the principle” of self-determination.86 These States recalled that
Resolution 1514 (and another resolution, on the use of force) had not been “unanimously
adopted or accepted as law by the General Assembly,” and “it could not be said that they
should be considered as reflecting a general practice accepted as law.”87
(Dec. 4, 1967) (negotiations of Aug. 7, 1967), p. 5 (Australia: “In its task of working out the content of the
principle [of equal rights and self-determination] in fuller detail, the Committee could find little help in the
Charter itself, since that content was nowhere spelt out. … In dealing with the principle, the Committee was
engaged on a genuine task of progressive development of international law.”); U.N. Doc. A/AC.125/SR.69
(Dec. 4, 1967) (negotiations of Aug. 4, 1967), p. 17 (Japan: “In spite of the clear statement in the Charter of the
principle of equal rights and self-determination of peoples, [the Japanese] delegation was not fully convinced
that such rights could be called rights under international law in the same sense as the right of sovereign equality
or other rights of States.”); U.N. Doc. A/AC.125/SR.68, supra note 83, pp. 3–4 (United States asserting that the
Charter principle of equal rights and self-determination was “a settled principle of modern international law” but
calling on the Committee to “prescribe the legal conditions and consequences of the principle and not limit itself
merely to reiterating its existence in a manner which shed[s] little light on its content”) (quotations respectively
at pp. 3, 4); U.N. Doc. A/AC.125/SR.44 (July 27, 1966) (negotiations of Apr. 13, 1966), para. 18 (Netherlands,
on the idea of setting forth legal elements for self-determination, remarking that “it was not always easy to
translate such fundamental concepts into a body of legal rules”); U.N. Doc. A/AC.125/SR.41 (July 27, 1966)
(negotiations of Apr. 11, 1966), para. 15 (France: “If the Committee came to the conclusion that the principle of
self-determination was a principle of international law … it would seem to be the Committee’s duty to study and
define the principle as such. Before one could lay down the particular obligations of States in pursuance of the
principle it seemed important to define the principle itself.”).
85 U.N. Doc. A/AC.125/SR.70, supra note 84, pp. 19–20 (quotation at p. 19). Accord, e.g., U.N. Doc.
A/AC.125/SR.93, supra note 84, p. 142 (Venezuela repeating these concerns in 1968); id., p. 139 (Syria
acknowledging the “divergence of views [among Committee members] concerning the nature of the rights
involved in the concept of self-determination, which led to further conflicts of opinion on the other aspects of
the principle”); id., pp. 143, 149 (India and France noting the Committee’s persistent inability to reach
consensus on self-determination).
86 1967 Report of the Special Committee on Friendly Relations, U.N. Doc. A/6799 (Sept. 26, 1967) [hereinafter
1967 FRD Report], para. 185. Accord, e.g., 1968 Report of the Special Committee on Friendly Relations, U.N.
Doc. A/7326 (1968) [hereinafter 1968 FRD Report], para. 147 (reporting on continued disagreement over
Resolution 1514); U.N. Doc. A/AC.125/SR.69, supra note 84, p. 10 (Canada stating that Resolution 1514 “was
an important political document” but Canada “did not regard that declaration as a mandatory source.”); U.N.
Doc. A/AC.125/SR.70, supra note 84, p. 8 (Australia finding “unacceptable” the notion that Resolution 1514
had a legally binding effect even though it “recognized [its] historic significance … as a landmark in the
General Assembly’s efforts to expedite self-determination”).
87 1967 FRD Report, supra note 86, para. 185. Accord, e.g., U.N. Doc. A/AC.125/SR.92, supra note 83, p. 122
(United Kingdom recalling its “reservations about some of the provisions of resolution 1514”); U.N. Doc.
A/AC.125/SR.44, supra note 84, para. 31 (in abstaining from Resolution 1514, Australia “had made clear that it
did not regard that resolution as a whole as representing a formulation of international law”); id., para. 34
(Canada: Resolution 1514 was “a political document which should have no more than persuasive force in the
Committee’s discussions regarding the legal element of the principle in question.”). See also U.N. Doc.
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3.24 Other delegations viewed Resolution 1514 as “the most authoritative pronouncement
on the principle [of self-determination] since the adoption of the Charter, and represented a
mandatory source with respect to the formulation of the principle by the Special
Committee.”88 Yet several of the States that believed self-determination was an international
legal right continued to express differing views on the scope of Resolution 1514’s
paragraph 6, on territorial integrity.89
3.25 It was not until 1969 that the Special Committee began to resolve some of these many
differences.90 Even at that late stage, as Cameroon observed, “while there seemed to be
general acceptance of the principle that all peoples should enjoy equal rights and the
inalienable right to self-determination, there was still a divergence of views as to the method
of implementing that right.”91 Japan stated that “it might be impossible to unify the points of
view, which were sometimes radically different, of all delegations.”92
3.26 Most aspects of the self-determination provision remained unresolved until April
1970.93 As a consequence, the Committee did not reach consensus on the principle of equal
rights and self-determination of peoples until it finalized the Friendly Relations Declaration’s
A/AC.125/SR.107 (Nov. 5, 1969) (negotiations of Sept. 4, 1969), p. 78 (Yugoslavia: It “was aware that there
was some difference of opinion as to whether [Resolution 1514] imposed obligations on Member States or
whether [it] primarily expressed the political intentions of the States which had voted for their adoption.”).
88 1967 FRD Report, supra note 86, para. 184. Accord, e.g., UN Doc. A/AC.125/SR.93 (Oct. 21, 1968)
(negotiations of Sept. 25, 1968), p. 140 (Poland considering Resolution 1514 as “the most valid expression,
since the adoption of the Charter, of the principle under discussion which it equated with a universally
recognized principle of international law”); U.N. Doc. A/AC.125/SR.69, supra note 84, p. 8 (Czechoslovakia:
Resolution 1514 was “the most authoritative pronouncement on the principle … since the adoption of the
Charter itself” and “a mandatory source for the purposes of the work now in progress.”).
89 Compare, e.g., U.N. Doc. A/AC.125/SR.91 (Oct. 21, 1968) (negotiations of Sept. 23, 1968), p. 114 (Ghana
asserting that the “sense of paragraph 6” seemed to be “that the principle of self-determination was limited to
political units already defined as countries or colonies (or subdivisions thereof … [)]”); U.N. Doc.
A/AC.125/SR.68, supra note 83, p. 10 (India: “Certain colonial and other Powers had attempted to distort the
true meaning of the principle of self-determination and had endeavoured to use it as a pretext to subvert the
independence and territorial integrity of established sovereign States. It was for that reason that the General
Assembly, in operative paragraph 6 … had stressed that the principle of self-determination could not be invoked
to justify ‘the partial or total disruption of the national unity and the territorial integrity’ of a sovereign State.”);
U.N. Doc. A/AC.125/SR.44, supra note 84, para. 40 (Guatemala reiterating its understanding of paragraph 6,
i.e., “that the principle of self-determination could not impair the right of territorial integrity or the right to the
recovery of territory”); U.N. Doc. A/AC.125/SR.43 (July 27, 1966) (negotiations of Apr. 12, 1966), para. 19
(Argentina: Self-determination included “the right of a people to determine the national affiliation of the space
which it inhabited and, consequently to demand territorial changes and oppose any cession of territory to which
[a people] did not expressly consent.”).
90 Compare, e.g., 1968 FRD Report, supra note 86, para. 192 (no progress by drafting committee on selfdetermination)
with 1969 Report of the Special Committee on Friendly Relations, U.N. Doc. A/7619 (1969),
para. 180 (setting forth a few paragraphs of agreed text, along with several other proposed paragraphs on which
no agreement had yet been reached).
91 U.N. Doc. A/C.6/SR.1160 (Nov. 26, 1969), para. 14 (remarks at meetings of the Sixth Committee to discuss
progress made by the Special Committee on Friendly Relations in 1969).
92 U.N. Doc. A/C.6/SR.1162 (Nov. 28, 1969), para. 13.
93 See 1970 Report of the Special Committee on Friendly Relations, U.N. Doc. A/8018 (1970) [hereinafter 1970
FRD Report], para. 68 (summarizing an April 10, 1970 oral report from the Drafting Committee Chairman,
which described persistent disagreement on key aspects of the draft resolution during informal negotiations).
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text on May 1, 1970.94 Upon finalizing the text, States on the Committee expressed general
support for including the self-determination provision95—even though it departed in material
ways from Resolution 1514.96 In fact, the Friendly Relations Declaration did not even
mention Resolution 1514. The General Assembly adopted the Friendly Relations
Declaration—without dissent or, importantly, abstention by any State—on October 24,
1970.97
3.27 This historical record belies any assertion that an opinio juris existed in 1965 or 1968
about a norm of self-determination in international law that would have prohibited
establishment of the BIOT. Even if one could conclude that there was a growing consensus
regarding the existence of a right of self-determination in international law, there was
manifestly no consensus as to the elements of a legal rule or its consequences, including
specific obligations on administering States. These facts foreclose finding that a specific rule
94 Id., paras. 84–85 (noting that “[t]he draft declaration contained in the report of the Drafting Committee
approved by the Special Committee” on May 1, 1970 “represents the consensus of the delegations,” and should
be read in conjunction with their statements for record included in the report and summary records (quotation at
para. 85)).
95 See, e.g., id., paras. 115, 118 (Venezuela); id., para. 123 (Romania); id., para. 140 (Italy); id., para. 150
(France); id., paras. 161–62 (Yugoslavia); id., paras. 173–77 (Canada); id., paras. 202–03 (Australia); id.,
para. 206 (Syria); id., paras. 218–219 (India); id., paras. 232–35 (United Kingdom); id., para. 243 (United Arab
Republic); id., paras. 265–70 (United States).
96 For some of the key ways the Friendly Relations Declaration differed from Resolution 1514, see United States
Written Statement, paras. 4.62–4.64. These differences included, for example, replacing the unconditional call
for independence with language recognizing other valid political status choices; eliminating the call for
immediate transfer of all powers to non-self-governing territories; and specifying that non-self-governing
territories have a separate status from the territory of administering States. Id., paras 4.62–4.63.
97 U.N. Doc. A/PV.1883 (Oct. 24, 1970), para. 8.
Mauritius suggests that Resolution 1514 was so universally accepted and supported by contemporary
practice that it constituted a law-declaring resolution. Mauritius Written Statement, paras. 6.31–6.32. Yet if any
General Assembly resolution could be considered to reflect the settled law on self-determination, it would be the
Friendly Relations Declaration. Unlike Resolution 1514, the self-determination section of the Friendly Relations
Declaration was developed by delegations featuring international lawyers, Edward McWhinney, The “New”
Countries and the “New” International Law: The United Nations’ Special Conference on Friendly Relations
and Co-Operation Among States, 60 AM. J. INT’L L. 1, 4 (1966), during debates that spanned five years. States
negotiating the Friendly Relations Declaration strove for—and achieved—consensus, in the hope that the
Declaration could thereby be regarded “as an authoritative statement of key principles of the Charter.” Robert
Rosenstock, The Declaration of Principles of International Law Concerning Friendly Relations: A Survey, 65
AM. J. INT’L L. 713, 714 n. 2 (1971); Rosenstock, supra note 70, at 54, (asserting that the Friendly Relations
Declaration “may be an authoritative interpretation of international law, adopted as it was unanimously and
stated as it was by many Members to be such—at any rate, if it is supported by state practice”); China Written
Statement, para. 8 (Friendly Relations Declaration “clearly recognizes the principle of self-determination of
peoples as an important principle of international law.”). Some commentators later characterized it as an
authoritative interpretation. See, e.g., OSCAR SCHACHTER, INTERNATIONAL LAW IN THEORY AND PRACTICE 119
(1991); Guyora Binder, The Case for Self-Determination, 29 STAN. J. INT’L L. 223, 236 (1993). See also e.g.,
Robert Rosenstock, U.S. Representative, Address Before the U.N. General Assembly Sixth Committee (Legal)
(Dec. 5, 1974), in DIGEST OF UNITED STATES PRACTICE IN INTERNATIONAL LAW 1974 17, 18 (Arthur W. Rovine
ed., 1974) (“Evolution has taken place in some of the most important provisions of the Charter. For example, if
in 1945 or 1950 we had asserted that the Charter granted peoples the right to self-determination, most members
would have disagreed. If in 1960 we had made the same assertion, many would have pointed out that all that
existed as a matter of law was a principle, not a right. Today [in 1974] if anyone questions the interpretation that
there exists a Charter right to self-determination, his views would be considered preposterous, or at least
anachronistic and wrong.”); U.N. Doc. A/C.6/SR.1517 (Dec. 9, 1974), pp. 16–20 (summarizing Rosenstock’s
address).
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of customary international law existed at the time that would have prohibited the United
Kingdom from establishing the BIOT.98
3.28 In light of arguments made in some of the written statements, two further
considerations about opinio juris warrant clarification. First, despite suggestions by some
States,99 the absence of “no” votes on Resolution 1514 or other resolutions does not by itself
demonstrate a general recognition among States that the resolution or particular paragraphs
reflected international law.100 For example, as the United States explained in its Written
Statement, several States that voted for Resolution 1514 did so despite concerns with the text;
abstaining States expressed support for the resolution’s ideals but plainly stated that it was
not a legal document; and even the resolution’s sponsors emphasized its aspirational
nature.101 These conditions show that many States’ votes on the resolution reflected a
political decision, not a legal position.
3.29 Second, some written statements suggested that General Assembly resolutions’ use of
the term “right” meant they enshrined a legal right with corresponding obligations.102 But it is
not legally dispositive that the General Assembly included words such as “right” and “shall”
in Resolution 1514 and other resolutions. In fact, the words “right” and “shall” appear in a
98 Cf. Nuclear Weapons, supra note 71, paras. 64–73 (Court finding no rule of customary international law
prohibiting any use of nuclear weapons, despite a large number of General Assembly resolutions “reveal[ing]
the desire of a very large section of the international community” to prohibit nuclear weapons, where “some
other States” continued to “assert the legality of the threat and use of nuclear weapons in certain circumstances
… [and] recall[ed] that they have always, in concert with certain other States, reserved the right to use those
weapons in the exercise of the right to self-defense against an armed attack threatening their vital security
interests,” even though no State had actually used such weapons since 1945 (quotations respectively at paras.
73, 66)).
99 See African Union Written Statement, para. 90; Belize Written Statement, para. 2.12; Djibouti Written
Statement, para. 31; Marshall Islands Written Statement, para. 18; Mauritius Written Statement, paras. 1.3, 6.27.
100 As the United States has noted elsewhere, “States may lend their support to a particular resolution, or
determine not to break consensus in regard to such a resolution, for reasons having nothing to do with a belief
that the propositions in it reflect customary international law.” John B. Bellinger III & William J. Haynes II, A
U.S. Government Response to the International Committee of the Red Cross Study Customary International
Humanitarian Law, 89 INT’L REVIEW RED CROSS 443, 445 (2007). Accord, e.g., U.S. 2018 ILC Comments,
supra note 70, p. 17 (“[T]he choice of whether to support or oppose a resolution may be made for political or
other reasons in lieu of a legal analysis of its content, or despite disagreement with the articulation or assessment
of a purported rule of customary international law addressed therein.”); ILC 2016 Conclusions on Customary
International Law, supra note 70, p. 107, para. 5 (“[N]egative votes, abstentions or disassociations from a
consensus, along with general statements and explanations of positions, may be evidence that there is no
acceptance as law, and thus that there is no rule.”); Stephen M. Schwebel, The Effect of Resolutions of the U.N.
General Assembly on Customary International Law, 73 AM. SOC’Y INT’L L. PROC. 301, 302 (1979) (“The
members of the General Assembly typically vote in response to political not legal considerations. They do not
conceive of themselves as creating or changing international law. … The issue often is one of image rather than
international law: states will vote a given way repeatedly not because they consider that their reiterated votes are
evidence of a practice accepted as law but because it is politically unpopular to vote otherwise.”); Gaetano
Arangio-Ruiz, The Normative Role of the General Assembly of the United Nations and the Declaration of
Principles of Friendly Relations, in 137 COLLECTED COURSES OF THE HAGUE ACADEMY OF INT’L LAW 419, 457
(1972) (explaining the importance of the “‘image’ factor” as a “driving force towards the proliferation of …
resolutions,” and stressing that “[w]hether members of the General Assembly really ‘mean it’ or not[] matters so
much as to make all the difference”).
101 See United States Written Statement, paras. 4.42–4.44 and sources cited therein.
102 See, e.g., African Union Written Statement, paras. 82–93, 102; Djibouti Written Statement, para. 31;
Mauritius Written Statement, para. 6.22.
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number of General Assembly resolutions and declarations that are indisputably nonbinding,
and did not otherwise reflect legal obligations. Prominent among these are the Universal
Declaration of Human Rights (UDHR)103 and the United Nations Declaration on the Rights
of Indigenous Peoples (UNDRIP).104 Numerous States have expressed their understanding
that both Declarations are nonbinding and aspirational.105
103 G.A. Res. 217 (III)–A, Universal Declaration of Human Rights, U.N. Doc. A/RES/217(III) (Dec. 10, 1948).
104 G.A. Res. 61/295, United Nations Declaration on the Rights of Indigenous Peoples, U.N. Doc.
A/RES/61/295 (Oct. 2, 2007), Annex.
105 With respect to the UDHR, see, e.g., U.N. Doc. A/PV.182 (Dec. 10, 1948), p. 904 (Poland: UDHR was “an
expression of principles with no legal force … and with only moral value.”); id., p. 905 (Poland: UDHR was not
a treaty and “contained no legal obligations.”); U.N. Doc. A/PV.181 (Dec. 10, 1948), p. 876 (Australia: “The
declaration represented a common ideal to be attained by all peoples of the world; it had no legally binding
character.”); id., p. 885 (Mexico: same); id., p. 888 (New Zealand: UDHR “had moral force only” and “imposed
no legal obligations.”); Eleanor Roosevelt, Address Before the U.N. General Assembly on the Adoption of the
Universal Declaration of Human Rights (Dec. 9, 1948), reprinted in U.S. DEPARTMENT OF STATE, HUMAN
RIGHTS AND GENOCIDE: SELECTED STATEMENTS 24, 25 (1949) (“[The UDHR] is not a treaty; it is not an
international agreement. It is not and does not purport to be a statement of law or of legal obligation. It is a
Declaration of basic principles of human rights and freedoms … .”); U.N. Doc. A/PV.180 (Dec. 9, 1948),
pp. 860–63 (summarizing Roosevelt’s address).
With respect to the UNDRIP, see, e.g., U.N. Doc. A/61/PV.108 (Sept. 13, 2007), p. 3 (Nepal, voting in
favor: The UNDRIP “do[es] not create any binding legal or political obligations.”); id., p. 5 (Turkey, voting in
favor: “The Declaration is not legally binding” but that “it can constitute an important policy tool … .”); U.N.
Doc. A/61/PV.107 (Sept. 13, 2007), p. 22 (United Kingdom, voting in favor: “[T]his Declaration is not legally
binding” but “will be an important policy tool … .”); id., p. 26 (Guyana, voting in favor: “[T]he Declaration is
political in character, as opposed to being a legally binding document … .”); id., p. 17 (Colombia abstaining and
clarifying that “the Declaration is not a legally binding norm”); id., p. 22 (Bangladesh abstaining and calling the
UNDRIP a “political Declaration”); id., p. 12 (Australia, voting “no”: “It is the clear intention of all States that
[the UNDRIP] be an aspirational declaration with political and moral force but not legal force.”); id., p. 13
(Canada, voting “no”: UNDRIP is “not a legally binding instrument … and its provisions do not represent
customary international law.” ). The four States that voted “no” on the UNDRIP later announced their support
for it with the caveat that it is not legally binding. See U.S. Announcement of Support for the United Nations
Declaration on the Rights of Indigenous Peoples (Dec. 16, 2010), reprinted in DIGEST OF UNITED STATES
PRACTICE IN INTERNATIONAL LAW 2010 262, 264 (Elizabeth R. Wilcox ed., 2011) (“The United States supports
the Declaration, which—while not legally binding or a statement of current international law—has both moral
and political force.”); Canada’s Statement of Support on the United Nations Declaration on the Rights of
Indigenous Peoples (Nov. 12, 2010), available at http://www.aadncaandc.
gc.ca/eng/1309374239861/1309374546142 (UNDRIP “is a non-legally binding document that does not
reflect customary international law”); Pita Sharples, New Zealand Minister of Maori Affairs, Announcement of
New Zealand’s Support for the Declaration on the Rights of Indigenous Peoples, Statement Delivered at the
Ninth Session of the U.N. Permanent Forum on Indigenous Issues (Apr. 19, 2010), para. 7, available at
http://www.beehive.govt.nz/sites/default/files/100420_UNDRIP.pdf (UNDRIP “expresses new, and nonbinding,
aspirations.”); Jenny Macklin, Australia Minister for Families, Housing, Community Services, and
Indigenous Affairs, Statement on the United Nations Declaration on the Rights of Indigenous Peoples (Apr. 3,
2009), available at
http://parlinfo.aph.gov.au/parlInfo/search/display/display.w3p;query=Id…
%22 (same).
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2. Security Council resolutions that reference Resolution 1514 do not indicate that
the Council Members considered it to reflect a relevant rule of customary
international law.
3.30 In its Written Statement, Mauritius cited Security Council resolutions adopted
between 1963 and 1968 that reference Resolution 1514 to suggest that the Council had
endorsed a legal right of self-determination.106
3.31 A close examination of the content of these resolutions and the conditions of their
adoption demonstrates that they, too, fail to provide evidence of opinio juris. Moreover, none
of the Security Council resolutions support Mauritius’s particular interpretation of Resolution
1514: that paragraph 6 of Resolution 1514 reflected a right to territorial integrity as a
component of the right of self-determination,107 and this right to territorial integrity
specifically required a plebiscite to approve any changes to a territory’s boundaries prior to
independence.108 None of the Security Council resolutions mentions territorial integrity or
plebiscites, and, as far as the United States is aware, these subjects were not raised by any
State during the discussions of these resolutions.
3.32 In fact, through its resolutions on the situations in Portuguese territories in Africa,
Southern Rhodesia, and South West Africa, the Council sought to promote peaceful
resolutions to political conflicts that were triggered by the antidemocratic actions of
governing authorities. The resolutions reference Resolution 1514 for the general principle
that the people of those territories should be able to decide their political status.
3.33 For example, Security Council Resolution 183 (1963) reiterated paragraph 2 of
General Assembly Resolution 1514 in order to establish common terms for a peaceful
resolution of the situation in the Portuguese territories.109
106 Mauritius Written Statement, paras. 6.34–6.37 (citing Security Council Resolutions 180, 183, 217, 232, 246,
and 253). Mauritius also cited several Security Council resolutions adopted after 1968. Id., paras. 6.35, 6.37 &
n. 640. Because these resolutions are not relevant to the determination of applicable law at the relevant time
period—either 1965, or at the latest, 1968—the United States will not address them in these Written Comments.
107 Id., para. 6.50(3).
108 See id., para. 6.58. Section III.C infra discusses Mauritius’s argument about plebiscites in detail.
109 Portugal claimed that its territories in Africa were integral parts of Portugal and rejected calls to promote
self-government or allow the peoples of those territories to choose their political status. See S.C. Res. 180, U.N.
Doc. S/RES/180 (July 31, 1963), para. 2; U.N. Doc. S/PV.1045 (July 26, 1963), para. 11 (China summarizing
Portuguese position). Specifically, in the context of discussions with African countries over the future of the
territories, Portugal asserted that the populations in its territories had already achieved “self-determination,”
which it defined as participation in administration and political life. See Report by the Secretary-General in
Pursuance of the Resolution Adopted by the Security Council at Its 1049th Meeting on 31 July 1963 (S/5380),
U.N. Doc. S/5448 (Oct. 31, 1963), pp. 4–5 (quoting the Portuguese Foreign Minister’s assertion that “‘selfdetermination
meant the consent of the people to a certain structure and political organization,’” and that the
territorial population’s participation in elections and political discussions “‘represented the free expression of
the wishes and will of the population and their participation in administration and in political life of the
territory’”). African countries responded that they could only accept a concept of self-determination that
included the right of the people of the territories to determine the future of their territories “and that they had the
right to opt out of Portugal.” Id., p. 5. Several Security Council Members hoped that, by referring to the
language on self-determination in Resolution 1514, further discussions between Portugal and African countries
would take place. U.N. Doc. S/PV.1082 (Dec. 10, 1963), para. 98 (Ghana: “[I]t was Portugal’s refusal to accept
the United Nations interpretation of self-determination that brought about a break-off of the conversations.”);
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3.34 Similarly, the other Security Council resolutions cited by Mauritius reflect support for
the general principle that the entire people of Southern Rhodesia and the people of South
West Africa should be able to freely choose their political status.110
3.35 In addition, several Security Council members either abstained from or qualified their
support for these resolutions, making it even more difficult to conclude that States intended to
endorse a legal rule. For example, three of the permanent members of the Security Council
abstained on Resolution 180 (1963).111 Moreover, some of the States that voted for
U.N. Doc. S/PV.1083 & Corr. 1 (Dec. 11, 1963), para. 95 (Brazil expressing support for further discussions,
including on the concept of self-determination); id., para. 105 (China: “The heart of the dispute … seems to lie
principally in the interpretation and application of the right of self-determination.”); id., para. 147 (United States
expressing hope that, building upon the interpretation of self-determination set forth in Security Council
Resolution 183, “we may move forward rapidly to bring about agreement on an early, peaceful, and full exercise
of self-determination, with full freedom of choice in the Portuguese territories”).
110 The resolutions on Southern Rhodesia responded to the declaration of independence issued by the European
settler minority and its establishment of a government. See S.C. Res. 217, U.N. Doc. S/RES/217 (Nov. 20,
1965), para. 1. The resolutions invoked Resolution 1514 in various ways intended to promote an exercise of
self-determination that reflected the freely expressed wishes of the entire people of Southern Rhodesia. None of
these references suggests that the Security Council intended to invoke a legal right of self-determination.
See, e.g., id., para. 7 (calling on the United Kingdom “to take immediate measures in order to allow the people
of Southern Rhodesia to determine their own future consistent with the objectives of General Assembly
resolution 1514 (XV)” (emphasis added)); S.C. Res. 232, U.N. Doc. S/RES/232 (Dec. 16, 1966), para. 4
(reaffirming “the inalienable rights of the people of Southern Rhodesia to freedom and independence in
accordance with … resolution 1514 (XV)” (emphasis added)); S.C. Res. 253, U.N. Doc. S/RES/253 (May 29,
1968), pmblr. para. 8 (recognizing “the legitimacy of the struggle of the people of Southern Rhodesia to secure
the enjoyment of their rights as set forth in the Charter of the United Nations and in conformity with the
objectives of General Assembly resolution 1514 (XV)” (emphasis added)). Several States also emphasized the
importance of participation by the entire people of the territory, not just the European settler minority. See, e.g.,
U.N. Doc. S/PV.1340 (Dec. 16, 1966), para. 46 (Uruguay: “[T]here can be no democracy in Southern Rhodesia
so long as the indigenous people does not exercise its inalienable power of self-determination … .”); id.,
para. 74 (Argentina supporting measures “to put an end … to the state of rebellion existing in Southern
Rhodesia and thus to allow the people of that Territory to exercise their right to self-determination in the
immediate future, without racial inequality … .”); U.N. Doc. S/PV.1265 (Nov. 20, 1965), para. 57 (United
States expressing its intent to implement relevant Security Council resolutions “to open the way for a process
that will permit all of the people of Southern Rhodesia to determine their own future by principles of selfdetermination
accepted by the United Nations”).
Resolution 246 addressed the continued activities of the Government of South Africa in the Territory of
South West Africa, including the detention and trial of several South West Africans. See S.C. Res. 246, U.N.
Doc. S/RES/246 (Mar. 14, 1968). It referred to Resolution 1514 in a preambular paragraph with respect to the
“right of the people and Territory of South West Africa to freedom and independence.” Id., pmblr. para. 3
(emphasis added). Several States condemned South Africa’s attempts to interfere with political developments in
South West Africa aimed at moving towards independence. See, e.g., U.N. Doc. S/PV.1397 (Mar. 14, 1968),
para. 9 (United Kingdom noting that its policy was “to enable all the people of South West Africa to proceed to
free and full self-determination and independence”); id., para. 28 (Soviet Union explaining that the Security
Council debate considered “the fate of the group of South West African patriots fighting to free their home land
from colonial and racist oppression, and against whom the Pretoria authorities have taken reprisals”); id.,
para. 51 (Hungary, criticizing the South African government’s activities because “[t]hey constitute a reckless
suppression of the fight for national independence”).
111 U.N. Doc. S/PV.1049 (July 31, 1963), para. 17 (France, United Kingdom, and United States abstaining); id.,
para. 27 (United States expressing support for a peaceful resolution of the situation in the Portuguese territories,
but explaining that it “abstained on the resolution primarily because we do not believe that is drafted either in
language or in form best calculated to achieve the results which we all seek as quickly and as harmoniously as
possible”); id., para. 44 (United Kingdom stating that it could not vote for paragraph 1, referencing General
Assembly Resolution 1514); id., para. 52 (France, while supportive of the political goals of the resolution,
explaining that “this resolution … is worded in such a way that in our opinion it exceeds the authority vested in
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Resolution 183 (1963) explained that it reflected political recommendations rather than legal
pronouncements.112
3.36 Further, several members of the Security Council supported a flexible approach to
self-determination, recognizing that the specific procedures for reaching that goal were up to
each administering State, and that the people of a territory were free to select any form of
political status.113 Thus, even those States that agreed on a general principle of selfdetermination
did not necessarily agree on specific rules for its application.
3. Grants of independence to numerous territories do not support the existence of
a rule of customary international law in the absence of opinio juris.
3.37 Although most of the written statements did not address state practice, a few
suggested that the independence of a large number of States in the 1950s and 1960s was in
itself evidence of then-existing legal obligations.114 As the United States explained in its
Written Statement, the historical record does not demonstrate extensive and virtually uniform
state practice during this period.115 Moreover, it must be shown that administering States, in
granting independence to territories, acted out of a belief that a rule of customary
international law required them to do so.
3.38 To be sure, several administering States decided in the late 1950s and early 1960s to
make it their national policy to support decolonization.116 These States frequently referred to
the Organization by the Charter”). These States also abstained in a vote to add paragraph 4, referencing
Resolution 1514, to Security Council Resolution 232. U.N. Doc. S/PV.1340, supra note 110, para. 93.
112 See U.N. Doc. S/PV.1080 (Dec. 6, 1963), para. 14 (Madagascar encouraging Portugal to implement the
“recommendations” contained in Resolution 180); U.N. Doc. S/PV.1083 & Corr. 1, supra note 109, para. 76
(United Kingdom: “We believe also that self-determination partakes in essence of politics, rather tha[n] of
obligation in law.”); see also id., para. 150 (United States explaining that its reservations on Resolution 180
continued to apply, and expressing hope that “Portugal will co-operate with the broad provisions of the
resolution, and especially in achieving its main objective: a peaceful solution of the situation in the Portuguese
territories, through the application of the principle of self-determination”).
113 See U.N. Doc. S/PV.1083 & Corr. 1, supra note 109, para. 52 (in the context of Resolution 183, “[t]he
Philippine delegation realizes that only Portugal can decide on the procedure and the phasing of bringing about
self-determination to its territories”); id., para. 66 (United Kingdom: “[T]he timing and method of implementing
self-determination is certainly the responsibility of the administering Power.”). See also U.N. Doc. S/PV.1080,
supra note 112, para. 31 (Sierra Leone: “What the African States wish to emphasize and would ask the Security
Council in any resolution adopted to state precisely is that in the exercise of self-determination, no choice
should be excluded … .”).
114 See, e.g., African Union Written Statement, paras. 96–98; Belize Written Statement, para. 2.13; Brazil
Written Statement, para. 18; Netherlands Written Statement, para. 3.7.
115 United States Written Statement, paras. 4.65–4.72.
116 See, e.g., John F. Kennedy, President of the United States, Address in New York City Before the General
Assembly of the United Nations (Sept. 25, 1961), available at http://www.presidency.ucsb.edu/ws/?pid=8352
(expressing U.S. support for the “continuing tide of self-determination” and the United States’ intention “to be a
participant and not merely an observer, in the peaceful, expeditious movement of nations from the status of
colonies to the partnership of equals”); U.N. Doc. A/PV.945 (Dec. 13, 1960), para. 134 (French delegate
discussing France’s pro-decolonization policy and quoting President Charles de Gaulle’s remarks in September
1960: “‘Regarding the whole movement of decolonization which is taking place all over the world, … the
emancipation of the peoples … is consistent both with the spirit of our country … and with the irresistible
movement set in motion by the world war and its aftermath. I … directed French policy along this path—the
path of emancipation—and for the past two years I have steered it in the same direction.’”); Harold Macmillan,
Prime Minister of the United Kingdom, Address to the South African Parliament (Feb. 3, 1960), reprinted in
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these policies during discussions surrounding Resolution 1514 and other U.N. resolutions.117
The historical record suggests, however, that the States that granted independence in these
years were motivated by non-legal considerations—such as political, financial, or
humanitarian considerations.118
3.39 For example, in the early 1960s the Netherlands repeatedly expressed its desire that
the people of West Irian, a Dutch non-self-governing territory, be permitted to decide
whether they wished to merge with Indonesia or opt for some other status.119 Yet in 1962, the
Netherlands concluded an agreement with Indonesia under which the territory passed to
Indonesia after less than a year of U.N. administration, without a prior determination of the
West Irianese people’s wishes.120 Speaking before the General Assembly, the Netherlands
explained that it had “resign[ed] itself to transfer of the territory to Indonesia without a
previous expression of the will of the population” because “[w]ar would have meant exposing
the Papuans and their country to death and destruction … .” 121
HAROLD MACMILLAN, POINTING THE WAY 473, 475 (1972) (“The wind of change is blowing through this
continent … . We must accept it as a fact, and our national policies must take account of it.”).
117 See e.g., U.N. Doc. A/PV.1065 (Nov. 27, 1961), para. 203 (with respect to Ruanda-Urundi, Belgium
declaring that “the final goal was the realization of the freely expressed wishes of the peoples concerned” and
expressing its desire that the territory become independent in 1962); id., para. 29 (France: “We did not wait for
[Resolution 1514] to find out where we wanted to go and what we wanted to do, and to do it. In the case of both
Trust and Non-Self-Governing Territories, we prepared for self-determination by granting selfgovernment
… .”); U.N. Doc. A/PV.937 (Dec. 6, 1960), para. 10 (United States: “No people supports the idea of
freedom and national independence more eagerly or more proudly than the people of the United States.”); U.N.
Doc. A/PV.933 (Dec. 2, 1960), para. 66 (Australia discussing its “common policies” with respect to two
territories administered by it, along with its “common aspiration of giving self-determination to the people in
both territories”); U.N. Doc. A/PV.925 (Nov. 28, 1960), para. 47 (United Kingdom: “Every action of the United
Kingdom in regard to these territories [under U.K. administration] is directed towards the building of new
nations, nations which will be united and free, and through which the people can realize their aspirations for
peace, independence, prosperity and individual freedom.”).
118 See, e.g., Anthony Low, The End of the British Empire in Africa, in DECOLONIZATION AND AFRICAN
INDEPENDENCE: THE TRANSFERS OF POWER, 1960–1980 33, 43–51, 70–72 (Prosser Gifford & Wm. Roger Louis
eds., 1988) [hereinafter Gifford & Louis] (describing British motivations to grant independence to African
colonies as stemming from numerous factors, including domestic political pressure, protests in the colonies, a
desire to avoid another crisis like that in Suez in 1956 and, above all, pressure from African nationalist
movements propelled by a “domino effect” of other States gaining independence); id., p. 42 (discussing
Belgium’s motivations for acceding to Congolese independence, including a desire to avoid the “appalling cost”
of suppressing the independence movement by force and domestic political pressure not to dispatch Belgian
troops); Keith Panter-Brick, Independence, French Style, in Gifford & Louis, supra, p. 73, 101 (describing the
decolonization of French Africa as “the combined handiwork of political forces within France and overseas”).
119 See, e.g., Letter Dated 7 October 1961 from the Permanent Representative of the Netherlands Addressed to
the President of the General Assembly: Memorandum on the Future and the Development of Netherlands New
Guinea, U.N. Doc. A/4915 (Oct. 9, 1961), para. IV (explaining the Netherlands’ policy as “aimed at the
speediest possible attainment of self-determination by the Papuan people”); The Question of West Irian (West
New Guinea), 1957 U.N.Y.B. 76, 78 (1958) (similar).
120 Agreement (with Annex) Concerning West New Guinea (West Irian), Aug. 15, 1962, 437 U.N.T.S. 292. The
General Assembly acknowledged the resolution of the Dutch–Indonesian dispute in G.A. Res. 1752 (XVII),
Agreement Between the Republic of Indonesia and the Kingdom of the Netherlands Concerning West New
Guinea (West Irian), U.N. Doc. A/RES/1752(XVII) (Sept. 21, 1962).
121 U.N. Doc. A/PV.1127 (Sept. 21, 1962), para. 188. As explained in United States Written Statement,
para. 4.71 n. 180, West Irianese wishes would only be ascertained years later through a process criticized for its
undemocratic elements.
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3.40 Such non-legal motivations do not constitute opinio juris, a belief by “[t]he States
concerned” that they were “conforming to what amount[ed] to a legal obligation.”122 Those
States that claimed that the independence of many States was itself evidence of then-existing
legal obligations have not provided the evidence needed to establish that administering States
granted independence to non-self-governing territories generally, or to specific territories,
based on a belief that international law required them to do so.123
4. The writings of publicists, particularly at the time, do not demonstrate the
emergence of a relevant rule of customary international law.
3.41 Some written statements referred to the work of certain authors in support of
arguments that the right of self-determination had become customary international law during
the relevant period.124 Their reliance on such sources is unavailing for at least two reasons.
3.42 First, views of publicists cannot serve as a substitute for the need to find support in
the relevant direct sources of law under the Court’s Statute—treaties and customary
international law.125 Under the Court’s Statute, the teachings of the most highly qualified
publicists are “a subsidiary means for the determination of rules of law.”126 The proponents
of the emergence of a new rule of customary international law would need to identify
adequate direct evidence of state practice, and of States’ beliefs about what international law
required at the time, and the citation of various publicists does not advance that purpose
unless they provide such direct evidence.
3.43 Second, academic views about a right of self-determination in the 1960s were much
more varied than some of the written statements have suggested. During the relevant period
many publicists argued that the required elements for the creation of customary international
law had not yet come into existence though the 1960s and even into the 1970s.127 This
122 North Sea Continental Shelf, supra note 66, para. 77. As the Court warned, “[t]he frequency, or even habitual
character[,] of the acts is not in itself enough.” Id.
123 Cf., e.g., Asylum Case (Colombia v. Peru), Judgment, I.C.J. Reports 1950, p. 266, 277 (finding no customary
rule on diplomatic asylum where, inter alia, state practice had been “so much influenced by considerations of
political expediency … that it is not possible to discern in all this any constant and uniform usage, accepted as
law”).
124 See, e.g., African Union Written Statement, paras. 117–127; Belize Written Statement, para. 2.15; Djibouti
Written Statement, para. 32; Mauritius Written Statement, para. 6.29.
125 See THE STATUTE OF THE INTERNATIONAL COURT OF JUSTICE 854 (Andreas Zimmerman et al. eds., 2d ed.
2012) (“[I]n marked contrast to the sources listed in the previous sub-paragraphs, jurisprudence and doctrine are
not sources of law—or, for that matter, of rights and obligations for the contesting States; they are documentary
‘sources’ indicated where the Court can find evidence of the existence of the rules it is bound to apply by virtue
of the three other sub-paragraphs.”); OPPENHEIM’S INTERNATIONAL LAW 42-43 (Robert Jennings & Arthur
Watts eds., 9th ed. 1992) (noting that reliance on the authority of writers as evidence of international law has
diminished in part due to “the practice of states evidenced by widely accessible records and reports”).
126 Statute of the International Court of Justice, art. 38(1)(d) (emphasis added).
127 See, e.g., GEORG SCHWARZENBERGER, 1AMANUAL OF INTERNATIONAL LAW 74 (5th ed. 1967) (indicating
that self-determination is “a formative principle of great potency, but not part and parcel of international
customary law”); GERALD VON GLAHN, LAW AMONG NATIONS: AN INTRODUCTION TO PUBLIC INTERNATIONAL
LAW 485 (1st ed. 1965) (indicating that “[n]o decisive ruling appears to have been delivered” on selfdetermination);
J.H.W. VERZIJL, 1 INTERNATIONAL LAW IN HISTORICAL PERSPECTIVE 323 (1968) (observing that
“[n]ot only does the asserted right [of self-determination] lack a specified and even specifiable holder, but its
substantive contents and the extent of its possible operation are also floating in the air”).
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disagreement among publicists paralleled that which was occurring among States during
Friendly Relations Declaration negotiations and elsewhere.128
3.44 Many scholars, much closer to the events of the day than we are a half-century later,
unequivocally disputed the establishment of a new principle of customary international law.
For example, Sir Robert Jennings wrote in 1963 that although self-determination
has legal overtones, it is essentially a political principle which may be a useful guide
in the making of political decisions. It is not capable of sufficiently exact definition in
relation to particular situations to amount to a legal doctrine; and it is therefore
inexact to speak of a “right” to self-determination if by that is meant a legal right.129
3.45 Surya Prakash Sinha concluded in 1968 that “it is not possible to claim that a practice
of states providing self-determination has been generally recognized by states as obligatory
under international law.”130 Similarly, Sir James Fawcett acknowledged in 1968 the
significant ongoing debate in the United Nations about whether self-determination was a
political principle or a legal right.131
3.46 It is true, as certain written statements pointed out,132 that Dame Rosalyn Higgins
characterized self-determination as an “international legal right” in 1963.133 But this
128 See, e.g., supra Section III.B.1.
129 R.Y. JENNINGS, THE ACQUISITION OF TERRITORY IN INTERNATIONAL LAW 78 (1963); see also id., p. 83
(“Resolution 1514 is essentially a political document … [n]or are the ‘rights’ of which it speaks legal rights of
the kind that could be vindicated before a court.”); J.A. de Yturriaga, Non-Self-Governing Territories: The Law
and Practice of the United Nations, 18 Y.B. OF WORLD AFFAIRS 178, 209–10 (1964) (emphasizing that most
scholars have reached the conclusion that General Assembly resolutions such as Resolution 1514 “are not
legally binding, but have a mere moral or political value” (quotation at p. 210)); Gerald Fitzmaurice, The Future
of Public International Law and of the International Legal System in the Circumstances of Today, in INSTITUT
DE DROIT INTERNATIONAL, LIVRE DU CENTENAIRE 1873–1973: EVOLUTION ET PERSPECTIVES DU DROIT
INTERNATIONAL 232–35 (1973) (acknowledging self-determination as a political principle but rejecting its
existence as a legal right); Hollis W. Barber, Decolonization: The Committee of Twenty-Four, 138WORLD
AFFAIRS 128, 129 (1975) (observing that “[t]he term ‘self-determination’ has been on many a lip for many a
year, but precise definition still eludes us”).
130 Sinha, supra note 70, p. 267; see also S. Prakash Sinha, Has Self-Determination Become a Principle of
International Law Today?, 14 INDIAN J. INT’L L. 332, 361 (1974) (concluding that “it cannot be said that the
principle of self-determination has acquired a general recognition by States as being obligatory”); L.C. Green,
Self-Determination and Settlement of the Arab-Israeli Conflict, 65 AM. SOC’Y INT’L L. PROC. 40, 46 (1971)
(noting that “there is still no right of self-determination in positive international law” and that “[i]t is insufficient
for a non-binding document to declare that the right is inherent when practice shows that has never been
regarded as the case”); M.C. Bassiouni, “Self-Determination” and the Palestinians, 65 AM. SOC’Y INT’L L.
PROC. 31, 32–33 (1971) (“The actual practice of states, particularly colonial and neo-colonial states, does not
demonstrate that the right [of self-determination], though recognized in principle, has been applied voluntarily
or consistently. It is certainly conceded that ‘self-determination’ is not part of customary international law, since
the custom and usage of member states of the world community do not evidence it by their practice.”).
131 J.E.S. Fawcett, The Protection of Human Rights on a Universal Basis: Recent Experience and Proposals, in
HUMAN RIGHTS IN NATIONAL AND INTERNATIONAL LAW 289, 291 (A. H. Robertson ed., 1968) (examining the
experience of the Special Committee on Decolonization and noting that “even [self-determination’s] political
implementation is not untroubled”); see also IAN BROWNLIE, PRINCIPLES OF PUBLIC INTERNATIONAL LAW 484
(1966) (“[A] number of governments continue to deny that [the principle of self-determination] exists as a legal
principle.”).
132 See African Union Written Statement, para. 117; Belize Written Statement, para. 2.15; Djibouti Written
Statement, para. 32; Mauritius Written Statement, para. 6.29.
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characterization must be viewed in context; notably, Dame Higgins accompanied that
statement with a contemporaneous recognition that “the extent and scope of the right [was]
still open to some debate.”134 As Professor D.J. Devine noted with respect to Dame Higgins’s
observation, “[s]elf-determination may certainly be a matter of international concern in that
the United Nations and its organs may urge the observance of the principle of selfdetermination.
But this is a very different thing from asserting that there is a duty to grant
self-determination and a correlative right in certain popular entities to self-determination.”135
3.47 Moreover, some four decades after her first observation, Dame Higgins herself
acknowledged that “[w]hen the Court addressed this concept in the South West Africa,
Namibia and Western Sahara cases, there were still many within the UN who insisted that
self-determination was nothing more than a political aspiration.”136
3.48 In sum, academic views about a right of self-determination in the 1960s cannot
substitute for the kind of evidence necessary to establish a new rule of customary
international law. In any event, many distinguished publicists concluded after reviewing the
available evidence that no such rule had emerged. Against this backdrop, this subsidiary
source cannot serve as a basis to conclude that a settled practice accompanied by opinio juris
existed.
C. There was no rule of customary international law that would have required the
United Kingdom to hold a plebiscite prior to Mauritius’s independence.
3.49 Of the States to address the issue in their written statements, all agreed that the
boundaries of a territory could be changed prior to independence with the consent of the
people. In other words, in exercising self-determination, a people could freely choose a status
that involved a change to the prior territorial boundaries.137
133 ROSALYN HIGGINS, THE DEVELOPMENT OF INTERNATIONAL LAW THROUGH THE POLITICAL ORGANS OF THE
UNITED NATIONS 103 (1963).
134 Id. Cf. HANS KELSEN, PRINCIPLES OF INTERNATIONAL LAW 79 (Robert W. Tucker ed., 2d ed., 1967) (“That a
right … has been transformed from a principle of political morality into a principle of law is not very significant
if the ambiguities that marked the former principle continue to mark the latter principle as well.”).
135 D.J. Devine, The Status of Rhodesia in International Law, 1974 ACTA JURIDICA 109, 194 n. 88 (1974); see
also id., 195–96 (reviewing the work of numerous publicists and concluding that the balance of juristic opinion
was against the existence of a right of self-determination); id., 187 (in addressing Common Article 1 of the
Human Rights Covenants, stating “[t]he fact that it was necessary to conclude a convention to provide for the
existence of the right [to self-determination], that the convention in question is subject to ratification and that the
number of States which have so far ratified it is minimal, all seem to eliminate any value which the Covenants
might have as declaratory evidence of the existence of such a right and to suggest that such a right does not exist
in customary law”); Robert A. Friedlander, Self-Determination: A Legal-Political Enquiry, DETROIT COLLEGE
OF LAW REV. 71, 81 (1975) (“Whether or not self-determination has evolved by way of United Nations ‘law’
into an international legal right is still a matter of considerable debate.”).
136 Rosalyn Higgins, Human Rights in the International Court of Justice, 20 LEIDEN J. INT’L L.745, 747 (2007).
137 See, e.g., United Kingdom Written Statement, para. 8.22; Mauritius Written Statement, para. 6.58; Belize
Written Statement, para. 3.9; Netherlands Written Statement, para. 3.18; cf. South Africa Written Statement,
para. 76 (arguing that uti possidetis applies before independence to fix a territories boundaries, but
acknowledging an exception where the parties agree otherwise).
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3.50 A few states asserted that the consent of the people of a non-self-governing territory
to changes to territorial boundaries could only be determined through a plebiscite.138 Even
assuming a requirement existed under customary international law in the mid-1960s to
ascertain the wishes of the people to boundary changes, there was no requirement for this to
be accomplished through a plebiscite.
3.51 As the Court has previously advised, an essential feature of self-determination
decisions is that they take into account the freely expressed wishes of the peoples
concerned.139 U.N. pronouncements on the subject, as well as practice, demonstrate a variety
of acceptable methods for determining the freely expressed wishes of the people.140
Plebiscites and referenda are common mechanisms for determining the freely expressed
wishes of the people, but not the only acceptable mechanisms. The General Assembly has
itself taken the position that “referendums, free and fair elections and other forms of popular
consultation play an important role in ascertaining the wishes and aspirations of the
people.”141
138 See, e.g., Mauritius Written Statement, para. 6.58 (noting that the only circumstances in which a newly
independent State was not formed from the totality of its prior territorial boundaries involved “an expression of
free consent on the part of the people through the medium of a plebiscite” or where “[maintaining the same
boundaries] proved impossible as a consequence of internal disturbances”); Djibouti Written Statement, para. 35
(arguing that consent to the establishment of the BIOT as a separate territory required a U.N.-supervised
plebiscite).
139 Western Sahara, supra note 14, paras. 55–59.
140 U.N. General Assembly articulations of self-determination repeatedly emphasize that it be exercised “freely”
and through “informed and democratic processes” without dictating a specific process for exercising selfdetermination.
See G.A. Res. 637 (VII), The Right of Peoples and Nations to Self-Determination, U.N. Doc.
A/RES/637(VII) (Dec. 16, 1952), para. 2; G.A. Res. 742 (VIII), Factors Which Should Be Taken into Account
in Deciding Whether a Territory Is or Is Not a Territory Whose People Have Not Yet Attained a Full Measure of
Self-Government, U.N. Doc. A/RES/742 (VIII) (Nov. 27, 1953), paras. 5–6; G.A. Res. 1514 (XV), Declaration
on the Granting of Independence to Colonial Countries and Peoples, U.N. Doc. A/RES/1514(XV) (Dec. 14,
1960), para. 2; G.A. Res. 1541 (XV), Principles Which Should Guide Members in Determining Whether or Not
an Obligation Exists to Transmit the Information Called for Under Article 73 e of the Charter, U.N. Doc.
A/RES/1541(XV) (Dec. 15, 1960), principles VII–IX; G.A. Res. 2625 (XXV), Declaration on Principles of
International Law Concerning Friendly Relations and Co-operation Among States in Accordance with the
Charter of the United Nations, U.N. Doc. A/RES/25/2625 (Oct. 24, 1970), Annex, “The Principle of Equal
Rights and Self-Determination of Peoples,” para. 4. Furthermore, as the U.N. Office of Legal Affairs has
explained, the history of U.N. practice “reveals that the General Assembly has acted on a case-by-case basis in
determining whether the modalities for the attainment of self-government by the peoples concerned satisfied the
requirements of the Charter and of the relevant Assembly resolutions.” Letter to the Chairman of the Special
Committee on the Situation with Regard to the Implementation of the Declaration on the Granting of
Independence to Colonial Countries and Peoples (Feb. 11, 1997), in 1997 U.N. Jurid. Y.B. 448, 450, U.N. Doc.
ST/LEG/SER.C/41 [hereinafter Resolution 1514 Implementation Letter]. See also ANTONIO CASSESE, SELFDETERMINATION
OF PEOPLES: ALEGAL REAPPRAISAL 73–74 (1995) (“[I]t was taken for granted that whenever it
appeared that the people of a colonial territory wished to opt for independence, it was not necessary to establish
this wish by means of a plebiscite or a referendum.”); MICHLA POMERANCE, SELF-DETERMINATION IN LAW AND
PRACTICE 32 (1982) (noting that in U.N. practice, “independence, by whatever method arrived at, is generally
not open to suspicion”).
141 G.A. Res. 54/90, Questions of American Samoa, Anguilla, Bermuda, the British Virgin Islands, the Cayman
Islands, Guam, Montserrat, Pitcairn, St. Helena, the Turks and Caicos Islands and the United States Virgin
Islands, U.N. Doc. A/RES/54/90 (Feb. 4, 2000), pmblr. para. 15.
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3.52 As a matter of state practice, general elections and other forms of “negotiations or
agreements between the representative bodies of the peoples”142 were used to exercise selfdetermination
throughout the postwar wave of decolonization.143 U.N. Member States did not
appear to complain that these means of ascertaining the people’s wishes were contrary to
international law.
3.53 For example, throughout this period the “consistent practice” of the United Kingdom
“was to ensure that independence had the support of the people of a territory either by
referendum or by means of a general election at which independence formed part of the
winning party’s mandate. In this way the principle of self-determination was regarded as
satisfied.”144 Notably, the States on the Special Committee on Decolonization, as well as the
Special Committee itself, were supportive of the use of elections and constitutional
conferences to transition British colonies to independence.145
3.54 The written statements of Mauritius and the United Kingdom described in detail the
process that led to Mauritius’s independence.146 Independence was achieved not through a
142 Resolution 1514 Implementation Letter, supra note 140, p. 449.
143 For example, in The Gambia, Kenya, Zambia, and Zanzibar, self-determination was exercised through a
combination of general elections (without U.N. participation) and negotiations and agreements between elected
officials and the administering State. See Report of the Special Committee on the Situation with Regard to the
Implementation of the Declaration on the Granting of Independence to Colonial Countries and Peoples, U.N.
Doc. A/5238 (1962), pp. 164, 167–68 (discussing the progress of constitutional conferences in Kenya); Report
of the Special Committee on the Situation with Regard to the Implementation of the Declaration on the Granting
of Independence to Colonial Countries and Peoples, U.N. Doc. A/5446/Rev.1 (1963) [hereinafter 1963
Decolonization Committee Report], pp. 206–08 (discussing general elections in Kenya as well as a
constitutional conference and general election in Zanzibar); Report of the Special Committee on the Situation
with Regard to the Implementation of the Declaration on the Granting of Independence to Colonial Countries
and Peoples, U.N. Doc. A/5800/Rev.1 (1965) [hereinafter 1964–65 Decolonization Committee Report], p. 10
(noting that Kenya and Zanzibar achieved independence); id., pp. 320, 323 (discussing the process towards
independence, including general elections and independence conferences, in The Gambia and Northern
Rhodesia (Zambia)). With respect to French Africa, although Guinea achieved independence through a
referendum, other French territories became independent following general elections, declarations of
independence, and negotiations between elected officials and the French government. See, e.g., RUPERT
EMERSON, FROM EMPIRE TO NATION: THE RISE TO SELF-ASSERTION OF ASIAN AND AFRICAN PEOPLES 74–76
(1960); Yves Person, French West Africa and Decolonization, in THE TRANSFER OF POWER IN AFRICA:
DECOLONIZATION 1940–1960 141, 168–70 (Prosser Gifford & Wm. Roger Louis eds., 1982).
144 IAN HENDRY &SUSAN DICKSON, BRITISH OVERSEAS TERRITORIES LAW 280 (2011).
145 See e.g., 1964–65 Decolonization Committee Report, supra note 143, p. 324, para. 67 (Mali, speaking on
behalf of a number of members of the Special Committee, “congratulated the United Kingdom Government for
having taken the measures which were to culminate in the granting of independence to Zambia and soon to
Gambia”); id., p. 324, para. 72 (Cambodia: “The path [towards independence] followed by Northern Rhodesia,
which was to become Zambia, had been in conformity with the recommendations of the Special Committee and
the General Assembly. … A tribute should also be paid to the United Kingdom Government, and it was to be
hoped that the example of Zambia would be followed by other Territories still under United Kingdom
administration.”); id., p. 325, para. 77 (Ethiopia: Its representative “welcomed the forthcoming attainment of
independence by Gambia; in his view, its political progress reflected the wishes of the Gambian people.”); 1963
Decolonization Committee Report, supra note 143, p. 214, para. 154 (India stating that the United Kingdom
“had displayed great wisdom” and hoped it “would use Kenya as a model in tackling similar problems in other
colonial territories”); id., p. 214, para. 161 (Iraq “was heartened by the fact that elections resulting in the
formation of a truly representative Government had at last been held in Kenya and that Kenya was to attain
independence”); id., p. 215, para. 163 (Iraq “was glad that elections had been held in Zanzibar” and adding that
“Zanzibar’s example could be usefully followed by other colonial territories”).
146 See Mauritius Written Statement, ch. 3; United Kingdom Written Statement, ch. III.
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popular plebiscite, but through decisions by the elected representatives of Mauritius
following a general election in which the parties favoring independence achieved a clear
majority.147 After independence, Mauritius was admitted to the United Nations as a Member
State without dissent.148 No State at the time contended that Mauritius’s independence was
somehow incomplete or that its decision to become independent did not reflect the wishes of
its people. It would therefore be highly unusual for the Court to advise now, fifty years later,
that a different process should have been used. Such a conclusion would have no basis in law.
* * *
3.55 Without question, the process of decolonization proceeded rapidly and successfully
during the 1950s and 1960s and enriched the international community immeasurably. But to
conclude that customary international law relevant to this case had crystallized by that time,
sufficient evidence of state practice accompanied by opinio juris would have to be
convincingly demonstrated.
3.56 Resolution 1514, and the other General Assembly resolutions cited by those who
argue in favor of a rule of customary international law, did not establish new law. They do
not reflect the actual settled practice of States or opinio juris about what the law required, and
references by the Security Council to these resolutions similarly do not reflect opinio juris.
3.57 Moreover, the fact that many States gained independence during this period is not
dispositive, but requires evidence—which is lacking—that administering States believed that
customary international law required them to grant independence to non-self-governing
territories that desired it. Publicists’ writings from the relevant time do not support the
conclusion that a specific rule of customary international law then existed that would have
prohibited the establishment of the BIOT. Finally, the historical record does not support the
assertion that a plebiscite was required before granting independence when other procedures
were commonly used to ascertain the wishes of the population.
3.58 Having considered the views of other States in their written statements, the United
States thus continues to believe that there was no international legal obligation based in treaty
or customary international law that would have prohibited the establishment of the BIOT. As
such, should the Court decide to address the questions in the General Assembly’s referral, its
answer to Question (a) should be that the process of decolonization of Mauritius was lawfully
completed. This result, in turn, would obviate the need to answer Question (b).
147 See Mauritius Written Statement, para. 4.2; United Kingdom Written Statement, para. 3.8(f).
148 See U.N. Doc. S/PV.1414 (Apr. 18, 1968); U.N. Doc. A/PV.1643 (Apr. 24, 1968).
36
CHAPTER IV
FURTHER OBSERVATIONS
4.1 For the reasons described in these Written Comments and in its Written Statement, the
United States does not deem it necessary to address Question (b) in any detail.149 Instead, in
this Chapter, the United States offers several observations on certain of the written statements
that do address this question.
4.2 Of particular note, Mauritius has asked the Court to opine on the relief to which it
should be entitled in the event its claim were upheld.150 This provides further evidence that
Mauritius pursued the referral as a means to adjudicate its sovereignty claim to the Chagos
Archipelago against the United Kingdom.
4.3 Because the specific assertions that Mauritius has made regarding its requested relief
rest on doubtful or erroneous assumptions, the United States wishes to bring to the Court’s
attention several points. Specifically, this chapter addresses three claims made by Mauritius
and others: (1) that it is the present-day people of Mauritius who hold any unexercised right
of self-determination; (2) that the transfer of the Chagos Archipelago to Mauritius must take
place immediately; and (3) that the current arrangements for the military facility on Diego
Garcia could readily continue under Mauritian sovereignty.
4.4 First, several statements assumed that any unexercised right of self-determination
with respect to the Chagos Archipelago would belong to the present-day people of
Mauritius.151 If, however, the Court were to determine that any right of self-determination
exists in these circumstances and remains to be exercised, the holder of that right may not be
the modern people of Mauritius.152 As the Republic of Seychelles highlighted in its
submission, a significant Chagossian population is present in the Seychelles.153 Chagossians
are also living in the United Kingdom.154 As such, determining who may hold the right of
self-determination with respect to the Chagos Archipelago today would be an exceedingly
complicated undertaking.
149 See supra para. 1.13; United States Written Statement, paras. 4.17, 4.75. Many other States did not address
Question (b) in their written statements, including those that believed that it would be inappropriate for the
Court to exercise its discretion to issue an advisory opinion, or urged the Court to exercise caution if it were to
do so. See, e.g., Australia Written Statement; Chile Written Statement; China Written Statement; France Written
Statement; Germany Written Statement; Israel Written Statement; Republic of Korea Written Statement;
Russian Federation Written Statement.
150 See, e.g., Mauritius Written Statement, paras. 7.42–7.61.
151 See, e.g., African Union Written Statement, paras. 66, 224; Argentina Written Statement, para. 51; Belize
Written Statement, para. 4.2; Djibouti Written Statement, para. 42; Mauritius Written Statement, para. 6.3(5);
Namibia Written Statement, pp. 3–4; Serbia Written Statement, para. 50; South Africa Written Statement,
para. 85.
152 See, e.g., STEPHEN ALLEN, THE CHAGOS ISLANDERS AND INTERNATIONAL LAW 286 (2004) (“The Chagos
Islanders … qualify as the beneficiaries of the entitlement to self-determination in relation to the BIOT.”).
153 Seychelles Written Statement, paras. 4, 6 (noting that “a significant number of the Chagossians were brought
to the Seychelles” and requesting “that the unique perspectives and legitimate concerns of the Seychellois
Chagossian community be taken into due consideration”).
154 United Kingdom Written Statement, para. 1.5 n. 7; id., para. 4.38.
37
4.5 Second, Mauritius argues that, if decolonization was not lawfully completed, it should
occur now through the immediate transfer of sovereignty over the Chagos Archipelago to
Mauritius.155 This argument presumes, incorrectly, not only that the decolonization of
Mauritius was not completed in 1968, but also that international law sets forth legal standards
for the timing of the decolonization process.156 This proposition is doubtful in light of actual
state practice. Rather, it is an issue that would be for Mauritius and the United Kingdom to
address bilaterally. It is not a suitable subject for the Court in the present proceedings.
4.6 Third, Mauritius devotes several pages to documenting its assurances that it
recognizes the existence of the military facility on Diego Garcia and is prepared to accept its
continued operation.157 Mauritius neglects, however, to mention how the United States has
responded to such assurances. In the lead-up to the General Assembly debate regarding the
referral resolution, for example, the U.S. Permanent Representative to the United Nations
sent a letter to the Permanent Representatives of all of the other U.N. Member States
informing them that the United States has no interest in entering into an arrangement with
Mauritius for this purpose.158 In the event it may be of interest to the Court, the United States
offers some context for this position.
4.7 The specific arrangement involving the facilities on Diego Garcia functions as a
partnership between the United Kingdom and the United States, two close and longstanding
allies. This is evinced by the absence of any “lease” or payment by the United States to the
United Kingdom,159 by the fact that both countries contribute to the management of the joint
facility, and by the fact that the United States and the United Kingdom consult on an annual
basis on all matters related to the facility, including on joint objectives and policies in the
region.160
4.8 While the relationship between the United States and Mauritius is cordial, it cannot
replicate the special relationship between the United States and United Kingdom. The United
States and United Kingdom are friends and allies with a particularly deep and strong bond,
grounded in a long history of cooperation, and cemented by shared goals and values. The
militaries of the two countries, and in particular their navies, work closely together. As U.S.
155 Mauritius Written Statement, paras. 7.10–7.41.
156 See, e.g., 1970 FRD Report, supra note 93, para. 266 (United States, commenting on the Friendly Relations
Declaration’s call for a “speedy” end to colonialism: “[R]easonable men might differ as to the pace of
development and how fast was ‘speedy.’”); see also supra note 79 and sources cited therein.
157 Mauritius Written Statement, para. 7.22.
158 Letter from Amb. Nikki Haley, U.S. Permanent Representative to the United Nations, to All Permanent
Representatives of the United Nations (June 16, 2017), available at
https://usun.state.gov/sites/default/files/organization_pdf/letter_to_p….
159 Agreement Concerning the Availability of Certain Indian Ocean Islands for the Defense Purposes of Both
Governments [hereinafter 1966 Agreement], United States–United Kingdom, Dec. 30, 1966, 18 U.S.T. 28,
T.I.A.S. 6196, 603 U.N.T.S. 273, para. 4.
160 See, e.g., U.S. Department of State, Military Exercises and Operational Coordination, at
https://www.state.gov/t/pm/iso/c21539.htm. See also Agreement Concerning a United States Naval Support
Facility on Diego Garcia, British Indian Ocean Territory, Feb. 25, 1976 , 27 U.S.T. 315, T.I.A.S. 8230, 1018
U.N.T.S. 372 (superseding 1966 Agreement, supra note 159, and containing a regular consultation requirement
at para. 3).
38
Secretary of Defense James Mattis said recently:
[T]he U.K. and U.S. maintain an unmatched, enduring special relationship that is not
an artificial or historical artifact. In fact, it’s a pathway for our future … . Our
countries have more than 200 years of shared history, over a century of shared
battlefield experiences, and a robust record of diplomatic cooperation in support of
our security interests.161
4.9 BIOT’s status as a U.K. territory is therefore central to the value of the joint facility
for the United States. The United Kingdom and the United States have jointly operated this
facility for decades.162 It plays a critical role in the maintenance of peace and security, both in
the Indian Ocean littoral region and beyond, and is a cornerstone of the close U.S.–U.K.
defense cooperation. During the June 2017 General Assembly debate on the advisory opinion
referral resolution, a number of States highlighted security issues, and explicitly referred to
the role of the facility in the region. These included not only the United States and United
Kingdom, but also the Indian Ocean littoral states of Australia, India, and Mauritius.163
4.10 The joint facility enables the United States and the United Kingdom to address a
variety of security challenges in the Indian Ocean together. Security concerns in the region
include not only the traditional threats of regional conflict, but other threats such as terrorism
and piracy, natural disasters, and various types of maritime crime, including trafficking in
persons and illicit drugs, as well as illegal, unreported, and unregulated fishing.164 The joint
base is well positioned to support efforts to address such threats. Prepositioned aircraft and
ships enable a rapid and flexible response to regional crises and conflicts. The base provides
161 James Mattis, U.S. Secretary of Defense, and Gavin Williamson, U.K. Secretary of State for Defense,
Remarks in London (Nov. 10, 2017), available at https://www.defense.gov/News/Transcripts/Transcript-
View/Article/1369834/remarks-by-secretary-mattis-and-secretary-williamson-in-london-uk/. In a subsequent
meeting between the two Secretaries in February 2018, Secretary Mattis again emphasized the value of the
special U.S.–U.K. relationship and reaffirmed the importance of credible defense capabilities. Dana W. White,
Chief Spokesperson, U.S. Department of Defense, Readout from Secretary James Mattis’ Bilateral Meeting with
U.K. Secretary of State for Defense Gavin Williamson (Feb. 1, 2018), available at
https://www.defense.gov/News/News-Releases/News-Release-View/Article/14…-
mattis-bilateral-meeting-with-uk-secretary-of-stat/.
162 See United States Written Statement, para. 2.7 (noting that the joint facility is operated pursuant to a series of
international agreements that have been registered with the United Nations Treaty Office).
163 See, e.g., U.N. Doc. A/71/PV.88 (June 6, 2017), p. 12 (United Kingdom: “[The facilities] make an essential
contribution to regional and global security and stability. Moreover, they contribute to guaranteeing the security
of the Indian Ocean itself, from which all neighboring states benefit, including Mauritius. The facilities play a
critical role in combating some of the most difficult and urgent problems of the twenty-first century, such as
terrorism, international criminality, piracy and instability in its many forms.”); id., p. 13 (United States: The
base contributes “considerably to regional and international security.”); id., p. 18 (Australia: “[T]he Diego
Garcia military base plays a pivotal role in the global fight against terrorism. We consider that it is in the interest
of all members of the General Assembly to ensure that there is no uncertainty about the status of that base that
could jeopardize its contribution to international peace and security.”); id., p. 14 (India: “India shares the
international community’s concerns about security in the Indian Ocean.”); id., p. 8 (Mauritius: “Mauritius is also
very much concerned about security in the world. That is why we have repeatedly said that we do not have any
problem with the military base … . Mauritius is committed to the continued operation of the base in Diego
Garcia under a long-term framework … .”).
164 See, e.g., Alice G. Wells, Acting Assistant Secretary of State for South and Central Asian Affairs and Acting
Special Representative for Afghanistan and Pakistan, Address at Indian Ocean Conference, Colombo, Sri Lanka
(Sept. 1, 2017), available at https://www.state.gov/p/sca/rls/rmks/2017/273825.htm.
39
logistical support for the U.K. and U.S. navies, and for U.S. and Allied missions in the Indian
Ocean and North Arabian Sea and beyond. In short, the arrangement involving the facilities
on Diego Garcia is grounded in the uniquely close and active defense and security partnership
between the United States and the United Kingdom.
40
CHAPTER V
CONCLUSION
5.1 For the reasons set forth in its Written Statement and herein, the United States
remains firmly of the view that the Court should exercise its discretion to decline to issue an
opinion in this case.
5.2 The Court has been presented with divergent views as to how it should respond to the
request before it. There is, however, clear convergence both on the fact that the Court has
discretion to decline a request and on the criteria for when it would be appropriate for the
Court to do so. Further, there is broad recognition that it would not be appropriate to provide
an advisory opinion that would have the effect of circumventing the fundamental principle of
consent to judicial settlement.
5.3 In its Written Statement, the United States submitted that the very circumstances the
Court has previously indicated may be compelling enough to withhold an advisory opinion
are manifestly present in this case. None of the statements submitted to the Court by other
States or organizations call into question the presence of these circumstances. In fact, the vast
majority affirm that the legal questions really in issue are directly related to the main point of
an ongoing bilateral dispute concerning sovereignty over territory. Indeed, that is the
fundamental reason for the referral.
5.4 As the Court has recognized, its discretion to decline to respond to a request for an
advisory opinion “exists so as to protect the integrity of the Court’s judicial function.”165 The
request presently before the Court illustrates precisely why the Court was granted such
discretion.
165 Kosovo, supra note 61, para. 29.