lh(1ucsl h• lhc Unikd Najion." General Assembly for au !\.th•isory Opinion on the
••Legal consct111cnccs ofthe sep1rnlion of me Chagos A1·chipclaJ?,o from Maurilius in 19(,5 ..
Wrillcn comments of the Unitc<l States or America on States· Written Replies
nr Sc Jtcmbcr I l, 2018 to the c. ucstions oscc.l b Jug 1 c Can ·ado·1·rindadc
I. The l lnitcd S1,1tcs offers three observations on the Wrillen Replies of States to the questions
posed by Judge Canc;ado-Trin<ladc on September 5 (hcrcinaller. ''the replies").
'J First. in their replies some States assert that a relevant rule of customary international law
existed at the relevant time. without supporting evidence or regard J'or the arpropriatc
methodology for dclerrnining such a rule's existence. The Cotn1's longstanding jurisprudence
holds Lhat in order to find the existence of a rule of customary international law, ''two
conditions must be rulfillcd. Not only must the acts concerned amount to a se/1/ed fJl'(lClice,
but they must also be such, or be 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 fi.e., opinio
juri,\·1:· 1 In other words, ·•within the period in question ... State practice, including that of
States whose interests arc specially affected, should have been both extensfre and virtually
un[jiJrm in the sense of the provision invoked;-and should moreover have occurred in such
a way as to show a general recognition that a rule of law or legal obligation is involved. "2
3. Despite many expressions of political and moral support for decolonization, including by the
United States and other administering powers, there was no opinio juris or "extensive and
virtually unifonn" State practice at the time Resolution 1514 was adopted, or through the end
of the 1960s, evidencing a specific customary international law rule that would have
prohibited the United Kingdom from establishing the British Indian Ocean Territory
(BIOT).3 The lack of opiniojuris is underscored by continued disagreements among States
about key elements of self-determination through April I 970, as the negotiating records of
1 North Sea Continental Shelf Judgment, I.C.J. Reports /969, p. 3, para. 77 (emphasis added). See also United
States Written Statement of March I, 2018, para. 4.27.
1 Id, para. 74 (emphasis added).
3 See United States Written Statement, paras. 4.32-4. 72.
...
thr..: Frir..:ndly Rdation.s Dr..:claration show.1 ·1·1u,:reforr..:. r..:onlrary to the assr..:rtinns submitted hy
a number or Stak.s in their rep) ir..:s. neither Resolutinn 15 I 4 nor the other resolutions citr.:d in
thr.: (iencral Assembly's questions rr.:!lcr.:tcd .spr.:cilic and rckvant rules of customary
international law applicable al the n.:levant tirnc.
4. Slates advam:ing these assertions likewise did not properly apply the Court's methodology
for detcrm ining the relevance or General Assembly resolutions to the fonriation of customary
international law. Gcncrnl Assembly resolutions may provide evidence or opinioJul'is
supporting the cxi,..,tencc of a ruli.: of customary international law. To determine whr.:thcr a
particular resolution provides such evidence. the Court has stressed that '"it is necessary to
look at its content 1md the conditions or its adoption.''5 The best evidence of States'
contemporaneous attitude toward a resolution arc the statements they make during
negotiation and adoption.6 Expressions of moral and political support arc not enough, nor is
the absence of votes against a resolution. 7 The fact that several States abstained on these
resolutions renecls the lack of consensus among States.8 Instead, the Court must he presented
with evidence sufficient to establish that States at the relevant time believed that international
law required the conduct in question. As set fo11h in detail in the United States Written
Statement and Oral Presentation,9 the negotiation and adoption records of the resolutions
cited in the questions do not demonstrate such a belief.
5. Second, the United States reiterates that, under the tem1s of the U.N. Charter, General
Assembly resolutions-with limited exceptions not applicable here-are not themselves
4 See United States Written Comments, paras. 3 .19-3.2 7.
5 legalif]• of the Threat or Use of Nuclear Weapons, Ad1,)fa'o1J' Opinion, I.C.J. Repol'ts /996, p. 226, para. 70.
6 See Report of the International Law Commission, 68th Sess .• U.N. Doc. An 1/10 (2016), ch. V: "Identification of
Customary International Law," p. 107, Commentary to Draft Conclusion 12, para. 6.
7 United States Oral Presentation, para. 49.
8 As we explained in our oral presentation. States are often able to support resolutions, or at least to not vote against
them, eve n where they do not agree with all of their terms, precisely because the resolutions are not binding and
States can explain their understanding of the resolution on the record. Id., para. 49. See also, e.g., Obligations
concerning Negotiations relating to Cessation of lhe Nuclear Arms Race and to Nuclear Disarmament (Marshall
Islands v. Pakistan), Jurisdiction and Admissibility, Judgement, f.C.J. Reports 20{6, p. 552, para. 53 (addressing
Pakistan's argument based on the parties' voting records on General Assembly resolutions: "[S]ome resolutions
contain a large number of different propositions; a State's vote on such resolutions cannot by itself be taken as
indicative of the position of that State on each and every proposition within that resolution, let alone of the existence
of a legal dispute between that State and another State regarding one of those propositions.").
9 See United States Written Statement, paras. 4.42-4.48; United States Oral Presentation, paras. 4555.
2
legally binding. 111 'l'hcrcl<1re. Stales arc mistaken when they charactcri1.c the resolutions cited
in !hr.: quc.slions :.is articulating --rules" or imposing. "obligation:.." or olhcrwisc requiring
"ohligalory compliance." Tile foct that .. mandatory term:-;:· such as "right" and ".shall:· may
appear in a resolution is not legally dispositive.
11
Many General /\ssemhly resolutions that
me inc.lisputahly nonbinc.ling use such terrns.
1:)
6. Finally. because the resolutions cited in the questions were not themselves hinding and Jid
not reflect a rule or customary international law that would have prohihitcd the establishment
or tl1e Bl(JI', there arc no legal consequences arising from them. /\s such. the United States
(Jocs not auc.lress the legal consequences proposed hy a number of Stales in their replies.
io
United States Written Statement, para. 4.28, n. 98.
11 See United States Written Comments, para. 3.29.
12 See id nn. I 03---05 and sources cited therein.
J
Written Comments of the United States of America on the Written Replies of other participants to the question put by Judge Cançado Trindade at the end of the hearing held on 5 September 2018