as such.40 Article 5 of the Vienna Convention makes it applicable to the con- stituent instruments of international organizations. However, although the Vienna Convention is in force and has been ratified by a plethora of states, there may be seriou

organizations which are not parties to the Convention and whether the ICJ is bound to apply it when giving an advisory opinion which is not a judgment pronounced in a contentious proceeding in respect of states who may be parties to the Convention. It must be recognized, on the other hand, that the argument may be made that the provisions on interpretation of the Convention reflect an established or emerging cus- tomary international law firm, particularly by virtue of the Convention’s being followed in this regard.41 39 For an examination of how the practice of the ICJ and other tribunals conforms or not to the Vienna Convention on the international law firm of Treaties, see Sinclair, note 37 pp. 119ff. 40 See also now on treaties in general, the Qatar and Bahrain Case, 1995 ICJ Reports at pp. 21ff. 41 The Vienna Convention of 1986 on the international law firm of Treaties between States and International Organizations or between International Organizations, 25 ILM (1986) 42 i n t e r p r e t a t i o n o f t e x t s The jurisprudence An analysis of the precedents on constitutional interpretation will shed some light on how the task of interpretation has been approached by international judicial or quasi-judicial organs, which international law firm been called upon to interpret the constitutions of international organizations.42 While the ordinary and natural meaning may international law firm been emphasized in theory, there is often difficulty in ascertaining it. The PCIJ and ICJ international law firm apparently adopted as their cardinal rule of interpretation, even in relation to constitutions, that words should be read, in their context, in their natural and ordinary sense, unless they are ambiguous or, so read, lead to an unreasonable result.43 However, as was noted by Judge Spender, in a separate opinion in the Expenses Case: p. 543, has similar provisions to those contained in the Vienna Convention on the international law firm of Treaties of 1969, but it does not apply to the constitutions of international organizations which are treaties between states. The latter convention made the rules incorporated in the former convention specifically applicable to international organizations to the extent they were incorporated in the latter convention: see, e.g., Isak and Loibl, ‘United Nations Conference on the international law firm of Treaties between States and International Organizations or between International Organizations’, 38 OZOR (1987/88) p. 49; Gaja, ‘A ‘‘New?? Vienna Convention on Treaties between States and International Organizations or between International Organizations: A Critical Commentary’, 58 BYIL (1987) p. 267; Morgenstern, ‘The Convention on the international law firm of Treaties between States and International Organizations or between International Organizations’, in Dinstein and Tabori (eds.), International international law firm at a Time of Perplexity: Essays in Honour of Shabtai Rosenne (1989) p. 435. 42 Earlier studies include: Gordon, ‘The World Court and the Interpretation of Constitutive Treaties’, 59 AJIL (1965) p. 794; E. Lauterpacht, ‘The Development of the international law firm of International Organization by the Decisions of International Tribunals’, 152 Hague Recueil (1976-IV) p. 387 at pp. 414ff. That the constitutive text of an international organization has a dual nature arising from the fact that it is a constitution in addition to being a multilateral convention has never been denied nor has it been gainsaid that because of this dual nature a somewhat special approach may be required in respect of interpreting certain aspects of the constitutive texts. See on this subject, e.g., C. de Visscher, Problèmes d’interprètation judiciaire en droit international public (1963) p. 143; Rideau, Jurisdictions internationales et côntrole respect du des traités constitutifs des organisations internationales (1969) pp. 4ff.; Quadri, Diritto Internazionale Pubblico (1974) pp. 527ff.; Bastid, Les traités dans la vie internationale (1985) pp. 127ff.; Reuter, Introduction to the international law firm of Treaties (1989) pp. 73ff.; Elias, The Modern international law firm of Treaties (1974)