1 Thirlway, H., ‘The Law and Procedure of the International Court of Justice 1960–1989 Part Three’, (1991) 62 BYIL 1Google Scholar, at 58.

2 McLachlan, C., ‘The Principle of Systemic Integration and Article 31(3)(c) of the Vienna Convention’, (2005) 54 ICLQ 279CrossRefGoogle Scholar, at 280.

3 See, e.g., Fragmentation of International Law: Difficulties Arising from the Diversification and Expansion of International Law, Report of the Study Group of the International Law Commission, Finalized by M. Koskenniemi, UN Doc. A/CN.4/L.682 (2006).

4 The expression is attributed to Xue Hanqin, currently judge at the ICJ; see McLachlan, supra note 2, at 281.

5 See, among others, Sands, P., ‘Treaty, Custom and the Cross-Fertilization of International Law’, (1998) 1 Yale HRDLJ 85Google Scholar; McLachlan, supra note 2; French, D., ‘Treaty Interpretation and the Incorporation of Extraneous Legal Rules’, (2006) 55 ICLQ 281CrossRefGoogle Scholar; Merkouris, P., ‘Debating the Ouroboros of International Law: The Drafting History of Article 31(3)(c)’, (2007) 9 International Community Law Review 1CrossRefGoogle Scholar.

6 United Nations Conference on the Law of Treaties, First Session, Vienna, 26 March–24 May 1968, Official Records, Thirty-Second Meeting, 172.

7 See, in this regard, Verhoeven, J., ‘Le point de vue des praticiens: Débats’, (2006) 2 RBDI 451Google Scholar.

8 1964 YILC, Vol. I, 765th meeting, at 280, para. 78, statement made by R. Ago during the ILC debates devoted to the Law of Treaties.

9 A good example is the Interpretation Act of Canada (Interpretation Act, R.S.C. 1985, c. I-21). According to Art. 3(2) of the Interpretation Act, ‘The provisions of this Act apply to the interpretation of this Act’. One can also mention Art. 15(1), which states that ‘Definitions or rules of interpretation in an enactment apply to all the provisions of the enactment, including the provisions that contain those definitions or rules of interpretation’.

10 Text of the set of draft guidelines constituting the Guide to Practice on Reservations to Treaties, provisionally adopted by the Commission, A/65/10, guideline 3.1.6.

11 For a recent discussion of the question, see Linderfalk, U., ‘Who Are “The Parties”? Art. 31, Para. 3 (c) of the 1969 Vienna Convention and the “Principle of Systemic Integration” Revisited’, (2008) 55 NILR 343CrossRefGoogle Scholar.

12 See, e.g., Palmeter, D. and Mavroidis, P., ‘The WTO Legal System: Sources of Law’, (1998) 92 AJIL 398CrossRefGoogle Scholar; Marceau, G., ‘A Call for Coherence in International Law: Praises for the Prohibition against Clinical Isolation’, (1999) 33 Journal of World Trade 125Google Scholar.

13 Fragmentation Report, ILC, supra note 3, at 237–9, paras. 470–472.

14 Panel Reports European Communities – Measures Affecting the Approval and Marketing of Biotech Products, adopted 29 September 2006, WT/DS291/R, WT/DS292/R, WT/DS293/R, paras. 7.68–7.71. The panel seized of an earlier case had decided to leave the question open (Panel Report Chile – Price Band System and Safeguard Measures Relating to Certain Agricultural Products, adopted 3 May 2002, WT/DS207/R, para. 7.85).

15 See, e.g., J. Pauwelyn, Conflict of Norms in Public International Law: How WTO Law Relates to Other Rules of International Law (2003), 257; McLachlan, supra note 2, at 315.

16 As suggested by Joost Pauwelyn, the subsequent agreements and the subsequent practice mentioned respectively by Arts. 31(3)(a) and 31(3)(b) are ‘only agreements and practice reflecting the common intentions of all parties to the treaty’, Pauwelyn, supra note 15, at 258.

17 See Art. 66 of the Vienna Convention; see also the Ann. to the Vienna Convention.

18 According to some members of the International Law Commission, the latter was not primarily concerned by the interpretation by dispute-settlement bodies and ‘was engaged in drafting a convention between States’; see 1964 YILC, Vol. I, 765th meeting, at 277, para. 34.

19 See, for such an argument, McGrady, B., ‘Fragmentation of International Law or “Systemic Integration” of Treaty Regimes: EC-Biotech Products and the Proper Interpretation of Article 31(3)(c) of the Vienna Convention on the Law of Treaties’, (2008) 42 Journal of World Trade 589Google Scholar, at 601–2.

20 J. Verhoeven, ‘Conclusions’, in C. Leben (ed.), Le contentieux arbitral transnational relatif à l'investissement: Nouveaux développements (2006), 365.

21 Status of Eastern Carelia, Advisory Opinion of 23 July 1923, PCIJ Rep. Series B No. 5, at 27. See also Rights of Minorities in Upper Silesia (Minority Schools), Judgment of 26 April 1928, PCIJ Rep., Series A No. 15, at 22; Corfu Channel (United Kingdom v. Albania), Judgment of 25 March 1948, [1948] ICJ Rep. 15, at 27; Anglo-Iranian Oil Co. (United Kingdom v. Iran), Judgment of 22 July 1952, [1952] ICJ Rep. 93, at 103; Monetary Gold Removed from Rome in 1943 (Italy v. France, United Kingdom and United States of America), Judgment of 15 June 1954, [1954] ICJ Rep. 19, at 32; Continental Shelf (Libyan Arab Jamahiriya/Malta), Judgment of 21 March 1984, [1984] ICJ Rep. 3, at 22; Land, Island and Maritime Frontier Dispute (El Salvador/Honduras: Nicaragua Intervening), Judgment of 13 September 1990, [1990] ICJ Rep. 92, at 133; East Timor (Portugal v. Australia), Judgment of 30 June 1995, [1995] ICJ Rep. 90, at 101.

22 On this concept, see L. Gross, ‘States as Organs of International Law and the Problem of Autointerpretation’, in G. A. Lipsky (ed.), Law and Politics in the World Community (1953), 59.

23 See Lake Lanoux case (France/Spain), Award of 16 November 1957, RIAA, Vol. 12, 281, at 310; Air Service Agreement of 27 March 1946 (United States of America/France), Award of 9 December 1978, RIAA, Vol. 18, 417, at 483.

24 See Judgments of the Administrative Tribunal of the ILO upon Complaints Made against Unesco, Advisory Opinion of 23 October 1956, [1956] ICJ Rep. 77, at 84; Difference Relating to Immunity from Legal Process of a Special Rapporteur of the Commission on Human Rights, Advisory Opinion of 29 April 1999, [1999] ICJ Rep. 62, at 77. For a recent discussion, see C. N. Brower and P. H. F. Bekker, ‘Understanding “Binding” Advisory Opinions of the International Court of Justice’, (2002) Liber Amicorum Judge Shigeru Oda 351.

25 C. Santulli, Droit du contentieux international (2005), 333.

26 On this concept, see H. Ascensio, ‘La notion de juridiction internationale en question’, (2003) La juridictionnalisation du droit international 163.

27 See Northern Cameroons (Cameroon v. United Kingdom), Judgment of 2 December 1963, [1963] ICJ Rep. 15, at 30. See also, Haya de la Torre (Colombia/Peru), Judgment of 13 June 1951, [1951] ICJ Rep. 71, at 83.

28 See Merkouris, supra note 5, at 21.

29 United Nations Conference on the Law of Treaties, supra note 6, at 172, para. 10.

30 See Sir H. Waldock, 1964 YILC, Vol. I, at 310, para. 10; Mr Yasseen, 1964 YILC, Vol. I, at 310, para. 11.

31 For recent discussions of this concept, see C. Quince, The Persistent Objector and Customary International Law (2010); Dumberry, P., ‘Incoherent and Ineffective: The Concept of Persistent Objector Revisited’, (2010) 59 ICLQ 779CrossRefGoogle Scholar.

32 As an Arbitral Tribunal pointed out, ‘international law is a broader concept than customary international law, which is only one of its components’, Pope & Talbor Inc v. Canada, Award in respect of damages of 31 May 2002, para. 46. A similar point was made within the WTO specifically in relation to the phrase ‘rules of international law’ used in Art. 31(3)(c), Panel Reports, supra note 14, para. 7.67.

33 The Special Tribunal for Lebanon defined ‘inherent jurisdiction’ as ‘the power of a Chamber of the Tribunal to determine incidental legal issues which arise as a direct consequence of the procedures of which the Tribunal is seized by reason of the matter falling under its primary jurisdiction’, Decision on Appeal of Pre-Trial Judge's Order Regarding Jurisdiction and Standing, 10 November 2010, para. 45.

34 R. Baxter, ‘Treaties and Customs’, (1970/I) 129 RCADI 27, at 81. An ICSID ad hoc Committee has recently made a similar point by stating that ‘except where norms of ius cogens are involved, a treaty is capable of modifying the rules of customary international law that would otherwise be applicable as between the States parties to the treaty. Indeed, often the very purpose of a treaty is to effect such a modification’, Azurix Corp. v. The Argentine Republic, ICSID Case No. ARB/01/12, Annulment Proceeding, Ad hoc Committee, 1 September 2009, para. 90.

35 Mavrommatis Jerusalem Concessions, Judgment of 26 March 1925, PCIJ Rep., Series A No. 5, at 27.

36 The famous dictum in the Georges Pinson case makes exactly the same point: ‘Every international convention must be deemed tacitly to refer to general principles of international law for all the questions which it does not itself resolve in express terms and in a different way’, Georges Pinson (France/United Mexican States), Award of 13 April 1928, RIAA, Vol. 5, 327, at 422. For a similar statement within the WTO, see Panel Report Korea: Measures Affecting Government Procurement, adopted 1 May 2000, WT/DS/163/R, para. 7.96.

37 See, e.g., Bartels, L., ‘Applicable Law in WTO Dispute Settlement Proceedings’, (2001) 35 Journal of World Trade 499CrossRefGoogle Scholar.

38 Military and Paramilitary Activities In and Against Nicaragua (Nicaragua v. United States of America), Judgment of 27 June 1986, [1986] ICJ Rep. 14.

39 R. Jennings, ‘The International Court of Justice and the Judicial Settlement of Disputes’, in R. Jennings, Collected Writings of Sir Robert Jennings, Vol. 1 (1998), 433.

40 Oil Platforms (Islamic Republic of Iran v. United States of America), Judgment of 6 November 2003, [2003] ICJ Rep. 161, at 281, para. 28 (Judge Buergenthal, Separate Opinion).

41 Reports of the Commission to the GA, 1966 YILC, Vol. II, at 219–20, para. 8.

42 Ibid.

43 United Nations Conference on the Law of Treaties, supra note 6, at 184, para. 72. See also, 1966 YILC, Vol. II, at 220, para. 9.

44 Territorial Dispute (Libyan Arab Jamahiriya/Chad), Judgment of 3 February 1994, [1994] ICJ Rep. 6, at 22, para. 41; Legality of Use of Force (Serbia and Montenegro v. Belgium), Judgment of 15 December 2004, [2004], ICJ Rep. 279, at 318, para. 100. See also, Case Concerning the Audit of Accounts between the Netherlands and France in Application of the Protocol of 25 September 1991 Additional to the Convention for the Protection of the Rhine from Pollution by Chlorides of 3 December 1976, Decision of 12 March 2004, RIAA, Vol. 25, 267, at 297, paras. 65–66.

45 Appellate Report United States: Import Prohibition of Certain Shrimp and Shrimp Products, adopted 12 October 1998, WT/DS58/AB/R, paras. 128–134.

46 Appellate Report United States – Anti-Dumping Measures on Certain Hot-Rolled Steel Products from Japan, adopted 24 July 2001, WT/DS184/AB/R, para. 60.

47 See Panel Reports, supra note 14, para. 7.70, stating that ‘Article 31(3)(c) mandates consideration of other applicable rules of international law’.

48 On this presumption, see the Fragmentation Report, supra note 3, at 25–8, paras. 37–43. See also the following document prepared by the Secretariat of the WHO: Review and Approval of Proposed Amendments to the International Health Regulations: Relations with Other International Instruments, A/IHR/IGWG/INF.DOC./1 (30 September 2004), para. 5; and Panel Report Indonesia – Certain Measures Affecting the Automobile Industry, adopted 2 July 1998, WT/DS54/R, WT/DS55/R, WT/DS59/R, WT/DS64/R, para. 14.28.

49 Right of Passage over Indian Territory (Portugal v. India), Preliminary Objections, Judgment of 26 November 1957, [1957] ICJ Rep. 125, at 142.

50 See, in this sense, the remarks of the German representative at the United Nations Conference on the Law of Treaties, supra note 6, at 172, para. 10. For a theoretical analysis of this presumption, see J.-M. Grossen, Les présomptions en droit international public (1954), 114–17.

51 On the presumption of good faith, see Lake Lanoux case, supra note 23, at 305. See also, mutatis mutandis, Mavrommatis Jerusalem Concessions, supra note 35, at 43; Certain German Interests in Polish Upper Silesia, Judgment on the Merits of 25 May 1926, PCIJ Rep., Series A No. 7, at 30. If the presumption of good faith is taken to be a rule of general international law, one could even say that its use is also dictated by the very logic of Article 31(3)(c), which refers to ‘any relevant rules of international law applicable in the relations between the parties’.

52 Thirlway, H., ‘The Law and Procedure of the International Court of Justice 1960–1989, Supplement, 2006: Part Three’, (2006) 77 BYIL 1Google Scholar, at 70. In support of the same proposition, see also J. Klabbers, ‘Reluctant Grundnormen: Article 31(3)(c) and 42 of the Vienna Convention on the Law of Treaties and the Fragmentation of International Law’, in M. Craven, M. Fitzmaurice, and M. Vogiatzi (eds.), Time, History and International Law (2007), 157.