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  • Fernando Lusa Bordin (a1)


Codification conventions and draft articles completed by the International Law Commission are often—and increasingly—invoked by courts, tribunals, governments and international organizations as ‘reflections of customary international law’. This article discusses the factors explaining the authority that these ‘non-legislative codifications’ have come to enjoy in international legal reasoning. Moving beyond the traditional explanations of codification conventions as evidence of State practice and ILC draft articles as the teaching of publicists, it considers how, against the backdrop of the uncertainty of customary international law, institutional factors (relating to authorship, representation and procedure) and textual factors (including prescriptive form and the absence of a distinction between ‘codification’ and ‘progressive development’) converge to convey the image that the resulting texts constitute the most authoritative restatement of the existing law. It then assesses this phenomenon in light of the political ideal of the international rule of law. While non-legislative codifications contribute to enhancing the clarity, consistency and congruence of international law, the fact that they may portray novel rules as reflecting existing law inevitably raises legality concerns.



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1 Caron, D, ‘The ILC Articles on State Responsibility: The Paradoxical Relationship between Form and Authority’ (2002) 96 AJIL 866.

2 UNGA Res 56/83 (2001).

3 United Nations, ‘Responsibility of States for internationally wrongful acts: Compilation of decisions of international courts, tribunals and other bodies’, Report of the Secretary-General, A/62/62, 1 February 2007, para 5, United Nations, ‘Responsibility of States for internationally wrongful acts: Compilation of decisions of international courts, tribunals and other bodies’, Report of the Secretary-General, A/65/76, 30 April 2010, para 7 and United Nations, ‘Responsibility of States for internationally wrongful acts: Compilation of decisions of international courts, tribunals and other bodies’, Report of the Secretary-General, A/68/72, 30 April 2013, para 5.

4 Jansen, N, The Making of Legal Authority: Non-legislative Codifications in Historical and Comparative Perspective (OUP 2010) 78.

5 ibid 32–3.

6 See eg the Introduction of Ibbetson and Lewis to The Roman Law Tradition (CUP 1994) at 3–5. This was especially true in the territory of modern Germany and the Netherlands, where a few centuries later the phenomenon of the ‘reception’ of Roman law took place, and the Corpus Juris was officially assimilated into the law of the different principalities; see Lee, , The Elements of Roman Law (4th edn, Sweet & Maxwell 1956) 23–4.

7 Jansen (n 4) 50–6.

8 ibid 72.

9 ibid 95.

10 See eg Baxter, RR, ‘Treaties and Custom’ (1970) 129/I Recueil des Cours 55.

11 See eg Peil, M, ‘Scholarly Writings as a Source of Law: A Survey of the Use of Doctrine by the International Court of Justice’ (2013) CJICL 148–9; Caron (n 1) 867; and the literature review in Sinclair, I, The International Law Commission (Grotius Publications 1987) 120–7.

12 The use of the term ‘legislative’ to refer to instruments of international law may be objectionable insofar as the international community has evidently not established a legislature. Yet, one can find references to ‘international legislation’ in the literature—in the sense of treaty rules of (potentially) universal application; eg Clapham, A, Brierly's Law of Nations (7th edn, OUP 2012) 103–11 —and this vocabulary is helpful to contextualize the present study within the debate on codification in general, and to facilitate the comparison of codification conventions and ILC draft articles with analogous instruments from domestic or transnational law.

13 By referring to codification conventions as non-legislative codifications, I mean to emphasize the role that these treaties perform when they are invoked as reflections of customary international law. Of course, in the relations between States parties, these conventions apply to them qua treaty.

14 One could mention, for example, the 1948 Convention on the Prevention and Punishment of the Crime of Genocide, adopted by the UNGA on the basis of a draft prepared by the UN Secretariat and revised by an ad hoc committee established by the Economic and Social Council. The UN Convention on the Law of the Sea, prominent among existing codification conventions, consolidated three early conventions that had originated from drafts of the ILC, the text of which was complemented by numerous new provisions drafted by the UN Conference on the Law of the Sea.

15 Raz, J, ‘Legitimate Authority’ in Raz, J, The Authority of Law (Clarendon Press 1979) 3.

16 J Raz, ‘The Claims of Law’ in Raz (n 15) 30.

17 See eg the Draft Statute for an International Criminal Court in ILC Yearbook 1994, vol II, pt 2, at 91ff. On the topic, see O'Keefe, R, ‘The ILC's Contribution to International Criminal Law’ (2007) 49 GYIL 201.

18 See the 1991 Draft articles on jurisdictional immunities of States and their property, ILC Yearbook 1991, vol II, pt 2, at 28ff.

19 Draft Articles on Diplomatic Protection, ILC Yearbook 2006, vol II, pt 2, at 24, ch IV.

20 See eg the summary of criticisms presented by Dugard, J, ‘How Effective is the International Law Commission in the Development of International Law? A Critique of the ILC on the Occasion of Its Fiftieth Anniversary’ (1998) 23 SAYIL 35–6.

21 cf Nolte, G, ‘The International Law Commission Facing the Second Decade of the Twenty-First Century’ in Fastenrath, U et al. (eds), From Bilateralism to Community Interest (OUP 2011) 781–92.

22 Reviewing its Programme of Work in 1973, the Commission noted that ‘it is to be expected that in the years ahead the codification convention will continue to be considered as the most effective means of carrying on the work of codification. Its preciseness, its binding character, the fact that it has gone through the negotiating stage of collective diplomacy at an international conference, the publication and wide dissemination of the conventions, all these are assets that will not lightly be abandoned’. ILC Yearbook 1973, vol II, 230, para 169.

23 cf Sinclair (n 11) 36.

24 Statute of the International Commission (UNGA Res 174 (II), Nov 1947).

25 ILC Yearbook 1956, vol 2, 106–7, para 9 (First Report, Fitzmaurice).

26 Villiger, M, ‘The 1969 Vienna Convention on the Law of Treaties: 40 Years After’ (2011) 344 Recueil des Cours 28.

27 ILC Yearbook 1962, vol II, 160, para 17 (Report of the ILC to the UNGA).

28 cf eg Zemanek, K, ‘Codification of International Law: Salvation or Dead End?’ in International Law at the Time of its Codification: Essays in Honour of Roberto Ago (Giuffre, A 1987).

29 It attests to the continuing success of the VCLT, however, that 18 States have ratified the Convention since 2000, including Saudi Arabia, Ireland, Vietnam and Brazil. cf the United Nations Treaty Collection <>.

30 For a detailed account—and an excellent analysis—of this paradigm shift with reference to the codification of the law of treaties and of the law of responsibility, see Villalpando, S, ‘Codification Light: A New Trend in the Codification of International Law at the United Nations’ (2013) VIII Brazilian Yearbook of International Law 117–55.

31 See Hurst, C, ‘A Plea for the Codification of International Law on New Lines’ (1946) 32 Transactions of the Grotius Society 144 and Jennings, R, ‘The Progressive Development of International Law and its Codification’ (1947) 24 BYBIL 303–7.

32 Tomuschat, C, ‘The International Law Commission: An Outdated Institution?’ (2007) 49 GYIL 91.

33 GA Res 55/153 (2001).

34 ILC Yearbook 2001, vol II, pt 2, 24–5, paras 61–7.

35 ibid 3, 24, para 63. See also Crawford, J and Olleson, S, ‘The Continuing Debate on a UN Convention on State Responsibility’ (2005) 54 ICLQ 959.

36 ILC Yearbook 2001, vol II, pt 2, 24, para 63. See Tomuschat (n 32) 96–7, describing the decision not to recommend the convening of a conference as ‘extremely clever’.

37 Fourth Report on State Responsibility (Crawford 2001) paras 21–26.

38 UNGA Res 56/83 (2001).

39 cf most recently UNGA Res 68/104 (2013).

40 See the summary of the debate at <>.

41 ILC Yearbook 1995, vol II, pt 1, 154–5, paras 170–9 (1st Report, Pellet). See also Seventeenth Report on Reservations to Treaties (Pellet 2011) 15–20.

42 UNGA Res 59/38 (2004).

43 Boyle, A and Chinkin, C, The Making of International Law (OUP 2007) 182. In the context of the codification of State responsibility, the fact that ‘[t]he law of State responsibility operates at an international level and does not require to be implemented in national legislation’ was raised as an argument in favour of not sending the draft articles to a diplomatic conference. Fourth Report on State Responsibility (Crawford 2001) para 25.

44 Pursuant to art 30(1) of the UN Convention on Jurisdictional Immunities of States and their Property, 30 ratifications are required for the Convention's entry into force.

45 United Nations, Survey of International Law in Relation to the Work of Codification of the International Law Commission, Memorandum submitted by the Secretary-General, UN Doc A/CN.4/1/Rev.1 (1949) 16, para 21.

46 Villalpando suggests that the versions of customary rules that the ILC provides tend to become ‘inseparable from our internal representations of such rules, to the point that [a] particular codification establishes itself as the unique and unavoidable instrument to found any legal reasoning in the field’—a phenomenon that he colourfully refers to as the ‘Santa Claus effect’. cf Villalpando (n 30) 120. Further, the view was expressed within the Commission that a report adopted or taken note of by the UNGA ‘would be seen as an authoritative study of current rules, State practice and doctrine aimed at providing guidance to States on their rights and responsibilities, thereby contributing to legal stability and predictability in international relations’, and that ‘such “soft law” instruments did have a decisive impact on international relations and the conduct of States, as evidenced by the jurisprudence of the ICJ’; ILC Yearbook 2001, vol II, pt 2, 24, para 64.

47 See eg Legal Consequences for States of the Continued Presence of South Africa in Namibia (South West Africa) notwithstanding Security Council Resolution 276 (1970) (Advisory Opinion), [1971] ICJ Rep 16, paras 94 and 96 (citing art 60 and noting that ‘[t]he rules laid down by the [VCLT] concerning termination of a treaty relationship on account of breach (adopted without a dissenting vote) may in many respects be considered as a codification of existing customary law on the subject’) and Fisheries Jurisdiction (United Kingdom v Iceland) (Jurisdiction of the Court) [1973] ICJ Rep 18, paras 24 and 36 (referring to arts 52 and 62 of the VCLT; the Court said that the latter could ‘in many respects be considered as a codification of existing customary law on the subject of the termination of a treaty relationship on account of change of circumstances’).

48 See eg Gabcikovo-Nagymaros Project (Hungary/Slovakia) [1997] ICJ Rep 7, para 99: ‘The Vienna Convention is not directly applicable to the 1977 Treaty inasmuch as both States ratified that Convention only after the Treaty's conclusion. Consequently only those rules which are declaratory of customary law are applicable to the 1977 Treaty.’

49 Gabcikovo-Nagymaros Project (Hungary/Slovakia) [1997] ICJ Rep 7, para 123: ‘The draft text of Article 12, which reflects this principle, was subsequently adopted unchanged in the 1978 Vienna Convention. The Court considers that Article 12 reflects a rule of customary international law; it notes that neither of the Parties disputed this.’ See also Continental Shelf (Tunisia/ Libyan Arab Jamahiriya) [1982] ICJ Rep 18, para 84.

50 See eg Conference for Peace in Yugoslavia, Arbitration Commission Opinion No 13 (16 July 1993) 32 ILM 1591, 1592, paras 2–4. See also J Crawford, ‘Remarks’ (1992) 86 ASILPROC 17; Tomuschat (n 32) 89; and Stahn, C, ‘The Agreement on Succession Issues of the Former Socialist Federal Republic of Yugoslavia’ (2002) 96 AJIL 379.

51 Jurisdictional Immunities of the State (Germany v Italy; Greece intervening) [2012] ICJ Rep 99, paras 66, 117 and 129. Noting that the UN Convention and the European Convention on State Immunity were not binding on both parties, the Court observed that ‘the provisions of these Conventions [establishing the ‘torts exception’ were] relevant only in so far as their provisions and the process of their adoption and implementation shed light on the content of customary international law’.

52 eg North Sea Continental Shelf (Federal Republic of Germany/Denmark; Federal Republic of Germany /Netherlands) [1969] ICJ Rep 3, paras 49–54.

53 Gabcikovo-Nagymaros Project (Hungary/Slovakia) [1997] ICJ Rep 7, paras 51–52. Similarly, in Difference Relating to Immunity from Legal Process of a Special Rapporteur of the Commission on Human Rights (Advisory Opinion) [1999] ICJ Rep 62, para 38, the Court declared that art 6 (now art 4) of the draft articles adopted on first reading reflected customary international law.

54 Application of the Convention on the Prevention and Punishment of the Crime of Genocide (Bosnia and Herzegovina v Serbia and Montenegro) [2007] ICJ Rep 43, paras 385, 398, 420 and 431 (in which the Court expressly referred to the text of arts 4, 8, 14(3) and 16). cf also Pulp Mills on the River Uruguay (Argentina v Uruguay) [2010] ICJ Rep 14, para 273 (referring to arts 34–37).

55 Ahmadou Sadio Diallo (Republic of Guinea v Democratic Republic of the Congo) (Preliminary Objections) [2007] ICJ Rep 582, paras 31 and 91 (although the Court did not find it necessary to assess the customary status of art 11(b)).

56 cf (n 3).

57 cf Behrami v France (App no 71412/01) and Saramati v France, Germany and Norway (App no 78166/01), ECtHR, 2 May 2007, paras 133–134 (applying art 5 of the ARIO—now art 6) and R (on the application of Al-Jedda) (FC) v Secretary of State for Defence (2007) UKHL 58, paras 5ff (Lord Bingham).

58 Legal Consequences of the Construction of a Wall in the Occupied Palestinian Territory (Advisory Opinion) [2004] ICJ Rep 136, para 159.

59 See, in this respect, the separate opinions of Judges Kooijmanns and Higgins. One reason that could explain the Court's decision not to quote the ASR was its general reluctance to refer to the notion of peremptory norms, on which art 41 is based. A couple of years later, the Court recognized the jus cogens character of the prohibition of genocide in Armed Activities on the Territory of the Congo (Democratic Republic of the Congo v Rwanda) (Jurisdiction and Admissibility) [2006] ICJ Rep 6, para 64.

60 Questions relating to the Obligation to Prosecute or Extradite (Belgium v Senegal) [2012] ICJ Rep 422, para 69. Art 48(1)(a) reads: ‘Any State other than an injured State is entitled to invoke the responsibility of another State in accordance with paragraph 2 if: (a) the obligation breached is owed to a group of States including that State, and is established for the protection of a collective interest of the group.’

61 Jurisdictional Immunities of the State (Germany v Italy; Greece intervening) [2012] ICJ Rep 99, para 93.

62 cf Villalpando, S, ‘On the International Court of Justice and the Determination of Rules of Law’ (2013) 26 LJIL 247, who notes that in instances in which the ICJ applied ILC draft articles, ‘the Court's finding that these provisions reflect customary international law is as brief and categorical as its own autonomous determinations of the rules of law, which apparently indicates an increasing trust placed by the Court on the Commission’.

63 US Diplomatic and Consular Staff in Tehran (United States v Iran) [1980] ICJ Rep 3, para 45. Curiously, while in this case the Court was in a position to apply the Conventions qua treaty law, since both parties to the dispute had ratified them, it still decided to pronounce on their customary status.

64 ICSID, Archer Daniels Midland Company and Tate & Lyle Ingredients Americas, Inc v the United Mexican States, Case No. ARB(AF)/04/05, Award, 21 November 2007, para 116.

65 cf art 38(1) of the ICJ Statute, generally recognized as an authoritative list of the accepted formal sources of international law. For the view that the three sources listed in art 38—treaty, custom and general principles—form the rule of recognition of international law, see Besson, S, ‘Theorizing the Sources of International Law’ in Besson, S and Tassioulas, J (eds), The Philosophy of International Law (OUP 2010) 180–1 and Paulus, A, ‘The International Legal System as a Constitution’ in Dunoff, J and Trachtman, J (eds), Ruling the World? Constitutionalism, International Law, and Global Governance (CUP 2009) 74.

66 Jansen (n 4) 34.

67 American Law Institute, ‘Report of the Committee Proposing the Establishment of an American Law Institute’ (1923) 1.

68 North Sea Continental Shelf (Federal Republic of Germany/Denmark; Federal Republic of Germany /Netherlands) [1969] ICJ Rep 3, paras 74–75.

69 On these questions, see eg Kammerhofer, G, ‘Uncertainty in the Formal Sources of International Law: Customary International Law and Some of Its Problems’ (2004) 15 EJIL, especially at 524–36. In an interesting analysis of custom as a source of international law, Lefkowitz suggests that a rule of recognition serves two distinct functions: an ‘ontological function’, which means that it is by reference to the rule of recognition that one can justify or criticize a ‘rule-governed practice for identifying norms as legally valid’; and an ‘authoritative resolution function’, which provides criteria for solving disputes about what the law is. The rule whereby custom is a law-creating fact would perform the ontological function, for it denotes ‘adherence to a shared normative standard for legal validity’. It would fall short, however, from satisfactorily performing the authoritative resolution function insofar as the vocabulary of State practice and opinio juris does not provide a workable methodology for identifying the particular valid norms of the system. See Lefkowitz, D, ‘(Dis)solving the Chronological Paradox in Customary International Law’ (2008) 21 CJLJ 146.

70 Clapham (n 12) 60.

71 cf eg Villalpando (note 62) 244. On the recent practice of the Court, see Alvarez-Jiménez, A, ‘Methods for the Identification of Customary International Law in the International Court of Justice's Jurisprudence: 2000–2009’ (2011) 60 ICLQ 681.

72 See the substantial first report submitted by Sir Michael Wood, Special Rapporteur for the topic, for consideration at the sixty-fifth session of the Commission in 2013. Doc A/CN.4/663 (17 May 2013).

73 Caron (n 1) 866.

74 Baxter (n 10) 100.

75 Jansen (n 4).

76 ibid 95.

77 art 13(1), UN Charter.

78 cf arts 2 and 9, ILC Statute, and General Assembly resolution 36/39 of 18 November 1981.

79 cf arts 3 and 10, ILC Statute.

80 For the list of current and past ILC members, access <>. It should be noted that several law professors are active practitioners in international law, while several governmental officials engage in academic activities.

81 cf Sinclair (n 11) 17.

82 Before the UN became an international organization of truly universal membership, a concern was voiced to increase the representativeness of international conferences. cf eg UNGA Res 2166(XXI) (1966), which, convoking a conference on the law of treaties, invited all members of the UN, members of specialized agencies and parties to the Statute of the ICJ, and envisaged the possibility that the UNGA extend the invitation to States not falling within any of these categories.

83 Anderson, DH, ‘Law-Making Processes in the UN System: Some Impressions’ (1998) 2 Max Planck Yearbook of United Nations Law 40.

84 See eg North Sea Continental Shelf (Federal Republic of Germany/Denmark; Federal Republic of Germany /Netherlands) [1969] ICJ Rep 3, paras 48–55 (reviewing the work and position taken within the Commission with respect to the provision that was eventually adopted as art 6 of the 1958 Geneva Convention on the Continental Shelf) and Jurisdictional Immunities of the State (Germany v Italy; Greece intervening) [2012] ICJ Rep 99, para 69 (referring to the work of the Commission when determining the scope of art 12 of the 2004 UN Convention on Jurisdictional Immunities).

85 North Sea Continental Shelf (Federal Republic of Germany/Denmark; Federal Republic of Germany /Netherlands) [1969] ICJ Rep 38, para 62.

86 On the working methods of the Commission, see generally Sinclair (n 11) 32–44.

87 Rosenne, S, ‘Codification Revisited after 50 Years’ (1998) 2 Max Planck Yearbook of United Nations Law 7.

88 cf in general F Berman, ‘The ILC within the UN's Legal Framework: Its Relationship with the Sixth Committee’ (2007) 49 GYIL 107. All in all, Berman sees this relationship as a ‘healthy one’ (at 125).

89 North Sea Continental Shelf (Federal Republic of Germany/Denmark; Federal Republic of Germany /Netherlands) [1969] ICJ Rep 3, para 62.

90 Baxter (n 10) 42–3.

91 That was the argument advanced by Denmark and the Netherlands in North Sea Continental Shelf, para 61.

92 Jansen (n 4).

93 ibid. Referring to the once highly authoritative De Jure Belli ac Pacis, Grotius' most important work, Lauterpacht reminds the reader, who may be tempted to criticize the book for its ‘methodological confusion’, that ‘in the seventeenth century eclecticism was as important as systematic accuracy’; Lauterpacht, H, ‘The Grotian Tradition in International Law’ (1946) 23 BYIL 52.

94 Dugard (n 20) 38. See also Schachter, O, ‘Law-Making in the United Nations’ in Jasentuliyana, N, Perspectives on International Law (Kluwer 1997) 134: ‘Even if the Commission's articles never attain treaty status, they achieve persuasive authority from the material presented in the reports and the agreement of the Commission. Much depends on the quality of this work, not simply as a register of past practice but as an adequate response to new conditions and felt needs.’

95 This is despite what could be seen as an excessive use of ‘saving clauses’ reserving questions on which no agreement could be reached or which were deemed not yet ‘ripe’ for codification. An example is provided by art 74(3) of the 1986 Vienna Convention on the Law of Treaties between States and International Organizations or between International Organizations, pursuant to which the Convention ‘shall not prejudge any question that may arise in regard to the establishment of obligations and rights for States members of an international organization under a treaty to which that organization is a party’. This clause raises the question of whether the rules contained in arts 34 to 37 of the Convention apply to members of an international organization, the upshot being that the Convention fails to take a position on one of the crucial issues arising from the subject-matter it sought to codify.

96 cf Sinclair (n 11) 34–5. In this respect, Ramcharan notes that ‘[t]he Commission has discovered through experience that the only way in which it can make progress is to seek consensus on the rules that it drafts. Experience has taught it that to adopt rules by majority vote would be a fruitless exercise, for once there is a serious division of views within the Commission which it has been unable to resolve, to push a decision through by a majority vote is a sure way of killing it in the General Assembly or at a subsequent codification conference.’ Ramcharan, BG, The International Law Commission: Its Approach to the Codification and Progressive Development of International Law (Nijhoff 1977) 3940.

97 cf eg Jennings (n 31) 301–3. As Crawford puts it, ‘“codifying” the law means stating what is to be, rather than—or at least as much as—stating what it has been. A codification is a formally complete statement of the law in the chosen field, which in a customary law system is likely to require further specification going beyond any basis in experience and practice.’ Crawford, J, ‘Multilateral Rights and Obligations’ (2006) 319 Recueil des Cours 453.

98 Lauterpacht, , ‘Codification and Development of International Law’ (1955) 49 AJIL 17.

99 As pointed out by Cançado Trindade, codification conventions ‘are bound to be long-lasting if they give expression also to the progressive development of the matter at issue, so as properly to fulfil the needs and aspirations of the international community as a whole’. cf Cançado Trindade, AA, International Law for Humankind: Towards a New Jus Gentium (Martinus Nijhoff 2010) 628.

100 Adopted by the General Assembly in resolution 174 (II) (1947), as amended by resolutions 485(V) (1950), 984(X) (1955), 985(X) (1955) and 36/39 (1981).

101 eg Pellet, A, ‘Responding to New Needs through Codification and Progressive Development’ in Gowlland-Debbas, V, Multilateral Treaty-Making: The Current Status of Challenges to and Reforms Needed in the International Legislative Process (Martinus Nijhoff 1998) 1516.

102 ILC Yearbook 1956, vol II, 255, para 26 (Report of the ILC to the UNGA).

103 ILC Yearbook 1974, vol II, 276, para 122 (Report of the ILC to the UNGA).

104 Boyle and Chinkin suggest that the absence of a ‘sharp distinction between codification and progressive development’ has made it possible for the ILC ‘to engage in a certain amount of creative law-making or law-reform’ and for ‘the ICJ and other tribunals to rely on ILC conventions without overtly enquiring whether particular articles represent existing law, revision of existing law or a new development of the law’. cf Boyle and Chinkin (n 43) 200.

105 It is telling that in North Sea Continental Shelf the Court found it determinant that the principle of equidistance had been ‘proposed by the Commission with considerable hesitation, somewhat on an experimental basis, at most de lege ferenda, and not at all de lege lata or as an emerging rule of customary international law’ to conclude that that was not ‘the sort of foundation on which Article 6 of the Convention could be said to have reflected or crystallized such a rule’ (para 61).

106 Berman (n 88) 127. See also Ramcharan (n 96) 104–5, who thought that whenever the Commission adopts a draft that will take the form of a convention, ‘[i]t would be imperative … to distinguish in each case what is existing law from what is put forward by way of progressive development’, lest the whole draft be perceived as a lex ferenda and governments be reluctant to refer to the work of the Commission. Ramcharan did not anticipate that the absence of such a distinction would have the effect of enhancing the authority of non-binding articles more often than not.

107 See, for example, ILC Yearbook 2001, vol II, pt 2, at 114 (on art 41 of the ASR, considering that ‘[i]t may be open to question whether general international law at present prescribes a positive duty of cooperation, and paragraph 1 in that respect may reflect the progressive development of international law’) and 127 (on art 48(2)(b) of the ASR: ‘This aspect of article 48, paragraph 2, involves a measure of progressive development, which is justified since it provides a means of protecting the community or collective interest at stake.’) See also ILC Report 2006, pt II, at 36, 48 and 83 (recognizing that elements of arts 5, 8 and 15 of the arts on Diplomatic Protection were exercises in progressive development).

108 ILC Report 2011, at 2–3, para 5. It should be noted that the fact that in the elaboration of the ARIO the ILC could only partially rely on practice and precedent does not mean that the articles should be considered an exercise in progressive development in the narrow sense. Rather, the articles were drafted on the basis of an analogy between States and international organizations that, to the extent that it proves to be a plausible systemic legal argument, may provide some justification to extending to those organizations rules originally devised for States.

109 UNGA Res 56/83 (emphasis added). The same formulation had been used when the UNGA took note of the ‘articles on nationality of natural persons in relation to the succession of States’ (UNGA Res 55/153 (2001)). It should be noted that before 2001 the UNGA had always referred to the output of the Commission as ‘draft articles’: cf Res 2166(XXI) (1966) (on the ‘draft articles on the law of treaties’); Res 3315(XXIX) (1974) (on the ‘draft articles on State succession with respect to treaties’) and Res 46/55 (1991) (on the ‘draft articles on jurisdictional immunities of States and their property’).

110 cf UNGA Res 62/67 (2008) and UNGA Res 66/100 (2011). Emphasis added.

111 Curiously, while the ICJ has consistently referred to the ‘Articles’ on State responsibility in its case law, it made reference to the ‘draft Articles on Diplomatic Protection’ in its judgment in Diallo; this was probably due to the fact that the latter judgment was given on 24 May 2007, that is, before the General Assembly formally took note of the ‘articles on diplomatic protection’ in Res 62/67.

112 Baxter (n 10) 42–3.

113 A similar example, though not belonging to a codification convention prepared by the ILC, is art I of the 1948 Convention on the Prevention and Punishment of the Crime of Genocide, in which the parties ‘confirm that genocide … is a crime under international law’.

114 cf eg the preambles of the 1969 Vienna Convention on the Law of Treaties, the 1978 Vienna Convention on Succession of States in Respect of Treaties and the 1982 UN Convention on the Law of the Sea. It is noteworthy that the preamble to the 1978 Vienna Convention affirms that ‘questions of the law of treaties other than those that may arise from succession of States are governed by the relevant rules of international law, including those rules of customary international law which are embodied in the Vienna Convention on the Law of Treaties of 1969’, thus confirming the customary status of provisions of the VCLT.

115 On considerations militating against ‘private codification’ and the reasons explaining the decline of the authority of institutions such as the Institut de droit international, see Abi-Saab, G, ‘La Commission du droit international, la codification et le processus de formation de droit international’ in United Nations, Making Better International Law: Proceedings of the United Nations Colloquium on Progressive Development and Codification of International Law (1998) 188–9.

116 See Peil (n 11) 152.

117 ibid 152. In fairness to publicists, it should be said that their work is frequently referred to by judges of the ICJ in their individual opinions. Yet, Peil's study concluded that the ILC ‘is far and away the most common source relied upon by the judges. Of the 3,857 references in the survey, 384 (approximately ten per cent) are to the ILC’. It should also be noted that other international judicial bodies such as the European Court of Human Rights and International Tribunal for the Law of the Sea are less economical than the ICJ in referring to publicists. But the general point about the different degree of authority enjoyed by the work of the ILC is also valid for those jurisdictions.

118 On the authoritativeness of judgments rendered by the ICJ, see eg Shahabuddeen, M, Precedent in the World Court (Grotius Publications 1996) 238–40.

119 In this regard, see Chen, Y, ‘Structural Limitations and Possible Future of the Work of the ILC’ (2010) 9 ChineseJIL 476–7.

120 Notably, in the context of the codification of State responsibility, members of the ILC expressed the view that ‘if the report of the Commission were adopted by resolution of the Assembly or taken note of, it would be seen as an authoritative study of current rules, State practice and doctrine aimed at providing guidance to States on their rights and responsibilities, thereby contributing to legal stability and predictability in international relations', and that ‘[a]doption in the form of a declaration would effectively place the burden on opposing States to prove that it was not binding’. ILC Yearbook 2001, pt I, 24, para 64). A similar view had been expressed by Baxter: ‘[t]he very existence of multilateral treaties declaratory or constitutive of law will induce even the non-parties to conform their conduct to some, if not all, of the rules of the treaty. … The dissenter's way is not easy when so many States are prepared to carry out the obligations of the treaty’ (n 10, 103). See also Sohn, L, ‘Unratified Treaties As a Source of Customary International Law’ in Bos, A and Siblesz, H, Realism in Law-Making: Essays on International Law in Honour of Willem Riphagen (Martinus Nijhoff 1986) 245–6 (recognizing the existence of a ‘clear presumption that the rule agreed upon at the conference, though the agreement [may not yet have been] ratified, has become an accepted rule of customary international law’).

121 Caron (n 1) 873. A similar opinion was recently voiced by the Special Rapporteur on formation and evidence of customary international law. In a note on the Articles on the Responsibility of International Organizations, Sir Michael Wood suggested that ‘it is the attitude of others, including courts and tribunals, that makes [the ILC a “dangerous place”], in the sense that undue homage is sometimes paid to its work, whether that work is good, bad or indifferent, and whatever stage it has reached’. His conclusion was that ‘courts and others should approach [the Articles] with a degree of circumspection’. Wood, M, ‘“Weighing” the Articles on Responsibility of International Organizations’ in Ragazzi, M (ed), The Responsibility of International Organizations: Essays in Memory of Sir Ian Brownlie (Nijhoff 2013) 65–6.

122 I follow Joseph Raz in referring to the rule of law as a ‘political ideal’ (cf J Raz, ‘The Rule of Law and its Virtue’ in Raz (n 15). One could also refer to the rule of law as a legal ideal, or as Raz himself suggests, a ‘legal virtue’.

123 UNGA Res 2625(XXV) (1970); UNGA Res 55/2(2000); UNGA Res 61/39(2006); 62/70(2008); and 63/443(2008).

124 Watts, A, ‘The International Rule of Law’ (1993) 36 GYIL 15.

125 Resolutions of the General Assembly, for instance, link legality with democracy, sustainable growth, eradication of poverty and protection of human rights. Hence Rosalyn Higgins's concern that the subject is being treated so broadly that it runs the risk of becoming ‘all things to all people’. R Higgins, ‘The ICJ, the United Nations System, and the Rule of Law’ (speech given 13 November 2006, available at <>) 14.

126 eg the absence of compulsory jurisdiction, problems of unaccountability of organs such as the UN Security Council and instances of endemic non-compliance. It is thus no wonder that writers strive to show that international law to an extent complies with rule of law principles in spite of everything, and conclude their analysis by affirming the need to achieve the international rule of law at a global level. See Crawford, J, ‘International Law and the Rule of Law’ (2003) 24 AdelLRev 10.

127 Watts (n 124) and Beaulac, ‘An Inquiry into the International Rule of Law’ (2007) EUI Max Weber Programme Series, Working Paper No 2007/14. Fuller's seminal work is The Morality of Law (Yale University Press 1964).

128 But see, for a more critical view, Waldron, J, ‘Are Sovereigns Entitled to the Benefit of the International Rule of Law?’ (2011) 22 EJIL 315.

129 This is the concept of ‘public authority’ conceived by a research project at the Max Planck Institute for Comparative Public Law and International Law— von Bogdandy, A et al. , ‘Developing the Publicness of Public International Law: Towards a Legal Framework for Global Governance Activities’ in von Bogdandy, A et al. , The Exercise of Public Authority by International Institutions (Springer-Verlag 2010) 11. Similarly concerned with the exercise of authority at the international level is the Global Administrative Law project, on which see Kingsbury, B et al. , ‘The Emergence of Global Administrative Law’ (2005) 68 LCP 15.

130 Villalpando (n 62) 249, suggesting that ‘governments appear to be agreeing to downgrade their intervention, by giving up the opportunity of negotiating conventions of codification’. One of the advantages of the current approach to codification is that States can benefit from great certainty and predictability in international affairs without having to officially express their consent to be bound by the rules and facing the domestic and international difficulties involved in the process. More fundamentally, one should also ask, as Jeremy Waldron does, to what extent sovereigns are entitled to the benefits of the rule of law as conceived at the domestic level. cf Waldron (n 127) 337–43.

131 Lauterpacht (n 98) 19: ‘It is probably a fact that the absence of agreed rules partaking of a reasonable degree of certainty is a serious challenge to the legal nature of what goes by the name of international law. That circumstance alone supplies cogent proof of the justification, nay, of the urgency of the task of codification of international law.’

132 Watts (n 124) 26. Speaking about the ‘basic idea’ of the rule of law, Raz remarks that the ‘basic intuition from which the doctrine of the rule of law derives’ is that ‘law must be capable of guiding the behaviour of its subjects’, that is, ‘that it must be such that they can find out what it is and act on it’; Raz (n 122) 214.

133 On international law as a system, see Conclusions of the Study Group on the Fragmentation of International Law: Difficulties Arising from the Diversification and Expansion of International Law’, International Law Commission, submitted to the General Assembly, UN Doc A/61/10 (2006) para 1. For the idea of completeness of the international legal system, see Lauterpacht, H, ‘Some Observations on the Prohibition of “non liquet” and the Completeness of the Law’ in Lauterpacht, E (ed), International Law (CUP 1970) 217. On standard views as to the relative determinacy (‘objectivity’) of international law, but taking a critical approach, see Koskenniemi, M, From Apology to Utopia (CUP 2005) 4158.

134 The Case of the S.S. ‘Lotus’ (France/Turkey), 1927 PCIJ Rep Series A No 10 at 18. In the Nicaragua case and the Nuclear Weapons advisory opinion, the premise adopted by the ICJ was that restrictions to the use of weapons were articulated in terms of prohibition. Military and Para-Military Activities in and against Nicaragua (Nicaragua v USA) (Merits) [1986] ICJ Rep 14, para 269; Legality of the Threat or Use of Nuclear Weapons (Advisory Opinion) [1996] ICJ Rep 226, para 52. Likewise, in the Kosovo advisory opinion, the Court analysed the lawfulness of the declaration of independence under general international law on the basis that State practice did not establish a prohibition. Accordance with International Law of the Unilateral Declaration of Independence in Respect of Kosovo (Advisory Opinion) [2010] ICJ Rep 403, para 79. For the idea of closure rules, see J Raz, ‘Legal Reasons, Sources and Gaps’ in Raz (n 15), 77.

135 Lauterpacht (n 133) 221–2. On the use of general principles of law and principles of international law in the jurisprudence of the ICJ, see Pulp Mills on the River Uruguay (Argentina v Uruguay) [2010] ICJ Rep 14, Sep Op Judge Cançado Trindade, paras 20–25.

136 See in general Alvarez, J, International Organizations as Law-makers (OUP 2005).

137 This does not mean, however, that the conclusion of multilateral treaties has become easier. The procedural developments of the last 50 years were accompanied by a radical expansion of the international community, which created new obstacles for the adoption of satisfactory treaties. On the shortcomings of modern treaty-making, see Alvarez (n 136) 370–93.

138 Abi-Saab (n 115) 195–7.

139 ibid 196–7. This phenomenon is also captured in Rene-Jean Dupuy's colourful metaphor of a ‘coutume sage’ being opposed to a ‘coutume sauvage’—cf Dupuy, ‘Coutume sage et coutume sauvage’ in Mélanges offerts à Charles Rousseau: La communauté internationale (1974) 75–87.

140 cf Charney, J, ‘Universal International Law’ (1993) 87 AJIL 546–7 (‘[t]he products of multilateral forums substantially advance and formalize the international lawmaking process. … Decisions taken at such a forum, support for the generally applicable rule, publication of the proposed rule in written form and notice to the international legal system call for an early response. … This process avoids some of the mysteries of customary lawmaking. It also permits broader and more effective participation by all states and other interested groups and allows a tacit consent system to operate legitimately’.)

141 cf Dupuy's idea of the ‘fonction révolutionnaire’ that custom occasionally performs, in which case ‘l'idée précède le fait; on assiste à une projection factuelle de l'idée politico-juridique’ (Dupuy (n 139) 84). For an insightful analysis of the emergence of customary law on the Continental shelf, making the point that custom is to be understood as a process, see Crawford, J and Viles, T, ‘International Law on a Given Day’ in Crawford, J, International Law as an Open System (Cameron May 2002) 69.

142 For a critical view of this approach, see Simma, B and Alston, P, ‘The Sources of Human Rights Law: Custom, Jus Cogens, and General Principles’ (1988–89) 12 AustYBIL 95–8.

143 Jennings, R, ‘Recent Developments in the International Law Commission: Its relation to the sources of international law’ (1964) 13 ICLQ 397.

144 Baxter (n 10) 73–4.

Thanks are due to Prof Guglielmo Verdirame, Prof Armin von Bogdandy, Dr Ana Kolarov, Dr Lucas Lixinski and Dr Maitê Schmitz for their thoughtful comments and kind edits.


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