1. As regards the articles on the law of treaties concluded between states, see ILC Report, A/5509 (F) (A/18/9), 1963, Ch. II, paras. 9–17; ILC Report, A/5809 (F) (A/19/9), 1964, Ch. II, paras. 12–24; ILC Report, A/6309/Rev.1 (F) (A/21/9), 1966, part I(E), paras. 11–12, and part II, Ch. II, paras. 9–38. As regards the articles on the law of treaties concluded between an international organizations and a state or between international organizations, see ILC Report, A/36/10, (F), 1981, Ch. III, paras. 88–129; ILC Report, A/37/10, (F), 1982, Ch. II, paras. 12–63.

2. See, e.g., B. Simma (ed.), The Charter of the United Nations: A Commentary (2002); J.-P. Cot, A. Pellet, M. Forteau, La Charte des Nations Unies, commentaire article par article (2005); S. Joseph, J. Schultz, and M. Castan, The International Covenant on Civil and Political Rights – Cases, Materials, and Commentary (2005); E. Denza, Diplomatic Law: A Commentary on the Vienna Convention on Diplomatic Relations (1998); A. Alen (ed.), A Commentary on the United Nations Convention on the Rights of the Child (2005); M. Weller (ed.), The Rights of Minorities in Europe: A Commentary on the European Framework Convention for the Protection of National Minorities (2005); C. H. Schreuer, The ICSID Convention: A Commentary on the Convention on the Settlement of Investment Disputes between States and Nationals of Other States (2001); Myron H. Nordquist (ed.), United Nations Convention on the Law of the Sea, 1982: A Commentary (1985–2004); L.-E. Pettiti (ed.), La convention européenne des droits de l'homme: commentaire article par article (1999); V. Constantinesco, J.-P. Jacqué, R. Kovar, and D. Simon, Traité instituant la CEE. Commentaire article par article (1992); J. Megret (ed.), Le droit de la Communauté économique européenne: commentaire du traité et des textes pris pour son application (1970–90).

3. 1969 Vienna Convention on the Law of Treaties, 1155 UNTS 331.

4. 1986 Vienna Convention on the Law of Treaties between States and International Organizations or between International Organizations, UN Doc. A/Conf. 129/15 (1986).

5. Case Concerning Delimitation of the Maritime Boundary in the Gulf of Maine Area (Canada/United States of America), Judgment, 12 October 1984, [1984] ICJ Rep. 246, at 299, para. 111:

A body of detailed rules is not to be looked for in customary international law which in fact comprises a limited set of norms for ensuring the co-existence and vital co-operation of the members of the international community, together with a set of customary rules whose presence in the opinio juris of States can be tested by induction based on the analysis of a sufficiently extensive and convincing practice, and not by deduction from preconceived ideas. It is therefore unrewarding, especially in a new and still unconsolidated field like that involving the quite recent extension of the claims of States to areas which were until yesterday zones of the high seas, to look to general international law to provide a readymade set of rules that can be used for solving any delimitation problems that arise. A more useful course is to seek a better formulation of the fundamental norm, on which the Parties were fortunate enough to be agreed, and whose existence in the legal convictions not only of the Parties to the present dispute, but of all States, is apparent from an examination of the realities of international legal relations.

6. See Art. 34 of the Statute of the International Court of Justice.

7. See, however, the proposed amendment of Art. 59 of the European Convention on Human Rights whereby ‘the European Union may accede to this Convention’; Protocol No. 14 to the Convention for the Protection of Human Rights and Fundamental Freedoms, amending the control system of the Convention CETS No. 194, open to signature since 13 May 2004. On this reform see generally A. Sicilianos, ‘La “réforme de la réforme” du système de protection de la CEDH’, (2003) 49 Annuaire Français de Droit International 611.

8. Monetary Gold Removed from Rome in 1943 (Italy v. France, United Kingdom and United States), Preliminary Question, Judgment, 15 June 1954, [1954] ICJ Rep. 19; East Timor (Portugal v. Australia), Judgment, 30 June 1995, [1955] ICJ Rep. 90. See also the recent case concerning the Armed Activities on the territory of the Congo (Democratic Republic of the Congo v. Uganda), Judgment, 19 December 2005, [1955] ICJ Rep. (not yet published), paras. 198–204.

9. Kelsen is probably the author who has expressed one of the most radical views on this, portraying customary international law as a mere creation of judges. See H. Kelsen, ‘Théorie du Droit international Coutumier’, (1939) 1 Revue Internationale de la Théorie du Droit 253, at 264, 266. The Corfu Channel case is usually referred to as one of the best examples of the extent of the role of judges in the identification of customary international rules. See Corfu Channel Case (United Kingdom v. Albania), Merits, Judgment, 9 April 1949, [1949] ICJ Rep. 4, at 22 and 28.

10. Military and Paramilitary activities in and against Nicaragua (Nicaragua v. United States of America), Merits, Judgment, 27 June 1986, [1986] ICJ Rep. 14, at 96 ff., paras. 175–182 and 187. See contra the dissenting opinion of Judge Jennings, ibid., at 529–34.

11. The enormous list of references to Art. 31 in the table of contents of the International Law Reports (ILR) is very telling regarding its extensive use in practice.

12. See the painstaking adoption of what became Art. 31 of the Vienna Convention. On this question see the commentary of J. M. Sorel, pp. 1301–7.

13. Examples of invalidity for conflict with jus cogens are very few and have pre-dated the Vienna Conventions, which is classically mentioned. See the 23 August 1939 German–Soviet Non-aggression Pact, also known as the Molotov–Ribbentrop Pact. Although officially labelled a ‘non-aggression treaty’, the pact included a secret protocol, in which the independent countries of Finland, Estonia, Latvia, Lithuania, Poland, and Romania were allocated to spheres of interest of the parties. The secret protocol explicitly assumed ‘territorial and political rearrangements’ in the areas of these countries. Subsequently all of them were invaded, occupied, or forced to cede part of their territory to either the Soviet Union or Germany, or both.

14. See J. Klabbers, ‘Accepting the Unacceptable? A New Nordic Approach to Reservations to Multilateral Treaties’, (2000) 69 Nordic Journal of International law 179; J. d'Aspremont, ‘Les réserves aux traités. Observations à la lumière de la Convention-cadre du Conseil de l'Europe pour la protection des minorités nationales’, (2002) 52 Recueil des travaux de l'Association Henri Capitant 487.

15. First Report of the Special Rapporteur, Mr Alain Pellet, 47th session of the ILC, 1995, A/CN.4/470 and Corr.1.

16. Official Records of the General Assembly, Fifty-Second Session, Supplement No. 10 (A/52/10), para. 157.

17. It was agreed early on that the form of the results of the study, which should be a guide to practice in respect of reservations, would take the form of draft guidelines with commentaries which would be of assistance to the practice of states and international organizations; these guidelines would, if necessary, be accompanied by model clauses. See the report of the ILC to the General Assembly, Fiftieth Session, Supplement No. 10 (A/50/10), para. 491. On the drafting of guidelines by the International Law Commission in general, see J. d'Aspremont, ‘Les travaux de la Commission du droit international relatifs aux actes unilatéraux des Etats’, (2005) 109 Revue générale de droit international public 163.

18. Cf. the 45 pages devoted to Art. 31 or the 46 pages dedicated to Art. 60.

19. See the ILC article on state responsibility for internationally wrongful act and the commentaries on the draft articles appears in Official Records of the General Assembly, Fifty-Sixth Session, Supplement No. 10 (A/56/10). See also the annex to General Assembly Resolution 56/83 of 12 December 2001.

20. See generally the reports of the ILC Special Rapporteur, UN Doc. A/CN.4/532, UN Doc. A/CN.4/541, UN Doc. A/CN.4/553, UN Doc. A/CN.4/564.

21. J. Combacau and D. Alland, ‘Primary and Secondary Rules in the Law of State Responsibility’, (1985) 16 Netherlands Yearbook of International Law 81.

22. See generally M. Koskenniemi, The Gentle Civilizer of Nations: The Rise and Fall of International Law 1870–1960 (2001).

23. See J.-P. Cot and A. Pellet, La Charte des Nations Unies: Commentaire article par article (1985). Cf. B. Simma (ed.), The Charter of the United Nations: A Commentary (1994).