2022 Statelessness & Citizenship Review 4(1) treaties or other international agreements.12 Importantly, where a state does not comply with the proposed norm, the norm will be affirmed if the state acknowledges its behaviour as wrongful or explains that its behaviour is not a violation due to factual or other reasons.13 However, there is no definitive classification of acts that can be identified as ‘practice’14 and no clear standards on the relative weight of various items of evidence.15 Ultimately, whether a proposed rule exists under customary international law is a question of the persuasiveness of the evidence, though there is no clear articulation of the burden of proof.16 The International Court of Justice (‘ICJ’) appears to demand less evidence when the existing examples of practice and opinio juris are not contradicted.17 However, in proving customary international law, we can apply a presumption that such a norm exists in certain situations. In the Case concerning Delimitation of the Maritime Boundary in the Gulf of Maine Area (Canada v United States of America) (‘Gulf of Maine’), a chamber of the ICJ noted that some customary international law was established by induction from practice and opinio juris, but other rules could be established without resorting to induction, when they served the purpose of ‘ensuring … coexistence and vital cooperation’ among states.18 It also appears that the Court is more likely to presume the existence of certain rules when they would have a lower impact on the state(s) concerned.19 This approach was also followed in the older Corfu Channel (United Kingdom of Great Britain and Northern Ireland v Albania) case (‘Corfu Channel’), where the Court cited ‘elementary considerations of humanity’ when it identified certain norms of customary international law.20 Nonetheless, the Court insists that it does not identify customary international purely on the basis of deduction from ‘humanitarian considerations’ or ‘moral principles’.21 Rather, the Court appears to apply an evidentiary presumption for the existence of state practice and opinio 12 13 14 15 16 17 18 19 20 21 See Jurisdictional Immunities Case (n 10) 122–23 [55]; Nicaragua Case (n 8) 111 [212]; Continental Shelf (Libya v Malta) Case (n 9) 27, 34–35; North Sea Continental Shelf Cases (n 3) 38–39; Asylum Case (n 3) 277; Lotus (n 3) 26; Furundžjia Trial Judgment (n 10) 66 [168]; ILC Draft Conclusions (n 3) [62] conclusions 6(2), 10(2). See ILC Draft Conclusions (n 3) [62] conclusion 15(2). See Report of the International Law Commission Covering its Second Session, 5 June–29 July 1950, UN Doc A/1316 (July 1950) pt II, 368 [31]: Evidence of the practice of States is to be sought in a variety of materials. The reference in article 24 of the Statute of the Commission to ‘documents concerning State practice’ (documents établissant la pratique des Etats) supplies no criteria for judging the nature of such ‘documents’. Nor is it practicable to list all the numerous types of materials which reveal State practice on each of the many problems arising in international relations. See Nuclear Weapons Advisory Opinion (n 11) [78] (Schwebel J), 584–85 [9]–[10] (Higgins J). See Anglo-Norwegian Fisheries Case (n 10) 191 (Reed J); ILA Statement of Principles (n 9) 13 principle 3: ‘What is suggested here is something analogous to (but not the same as) the well-known distinction in the law of evidence between the admissibility of evidence and its weight (convincingness)’. See Jurisdictional Immunities Case (n 10) 131–32 [72]. See Gulf of Maine Case (n 9) 22 [111]. Frederic L Kirgis, ‘Custom on a Sliding Scale’ (1987) 81(1) American Journal of International Law 146, 148: ‘When the stakes are not as high, international decision makers have not been as quick to find restrictive customary rules’. See Corfu Channel (United Kingdom of Great Britain and Northern Ireland v Albania) (Judgment) [1949] ICJ Rep 4, 22 (‘Corfu Channel Case’). See South West Africa (Ethiopia v South Africa; Liberia v South Africa) (Judgment) [1966] ICJ Rep 6, 34 [49]–[50]. 116