CYIL vol. 13 (2022)

LYUBOMIR L. SAKALIYSKI CYIL 13 ȍ2022Ȏ possible parties to treaties 28 . Having in mind that the ILC was tasked with codifying already existing customary international law and has done so in relation to treaty law with the two sets of draft articles it produced, it should be stressed that the fact that the VCLT II is not in force and has a very limited number of States signatories to it does not negate the fact that both the draft articles and the text of the VCLTs are codification of the already existing customary international law on treaties. The ILC further elaborates on the matter in its Draft Conclusions on Identification of Customary International Law 29 , where it has found in Conclusion 11 that a treaty provision may reflect customary international law if the custom already existed 30 . In its commentary 31 the ILC does not mention that the treaty should be in force. Extensive state practice on the matter supports the customary status of the VCLT II’s treaty definition, as there are thousands of treaties between States and IOs, even more so – seven of the parties to the JCPoA are parties to safeguards agreements and voluntary offer agreements with the International Atomic Energy Agency (IAEA, the Agency) 32 . The EU has not concluded a safeguards agreement with the IAEA because of the different status of its member States as per the Non-proliferation treaty (NPT) 33 , but it has concluded numerous treaties with States and other IOs 34 . Thus, not only it is evident that the definition of a treaty the VCLT II provides is a reflection of customary international law, but that all the parties to the JCPoA conduct their (state) practice according to that definition of a treaty. The VCLTs having codified the customary international law on treaties have not done so “verbatim”. This clarification is very important as both the draft articles and the VCLTs provide that definition of a treaty and its constituent elements are respectively only for the purposes of the draft articles 35 and the VCLTs 36 . Authors seem to have varying opinions on the matter, as some support this view 37 , while others disagree 38 . It must be noted that while tasked with codifying customary international law the ILC normally produces draft articles, which are then presented to the United Nations General Assembly (UNGA) as a draft text to a proposed treaty 39 , the VCLTs in these cases. Thus, the draft articles were intended as texts of treaties and no treaty, regardless of the number of its State parties, could claim to establish rules intended to be applied to anything more than for the purposes of said treaty. 28 VCLT II (n 5) Art. 2(1)(a). 29 ILC, ‘Report of the International Law Commission on the Work of its 70 th Session’ (30 April – 1 June and 2 July – 10 August 2018) UN Doc A/73/10, Text of the draft conclusions on identification of customary international law, p. 119. 30 Ibid. Conclusion 11, p. 143. 31 Ibid. pp. 143-146. 32 IAEA Docs INFCIRC/193, INFCIRC/214, INFCIRC/369, INFCIRC/290, INFCIRC/327, INFCIRC/263, INFCIRC/288. 33 Treaty on the Non-proliferation of Nuclear Weapons (adopted 1 July 1968, entered into force on 5 March 1970) 729 UNTS 161. 34 Council of the EU, Treaties and Agreements Database , accessed 15 April 2022. 35 ILC Report (n 22), Art. 2(1); ILC Report (n 27), p. 17, Art. 2(1). 36 VCLT (n 4), Art. 2(1).; VCLT II (n 5), Art. 2(1). 37 VILLIGER, M. E. Commentary on the 1969 Vienna Convention on the Law of Treaties (Martinus Nijhoff Publishers, Leiden, Boston 2009) p. 72. 38 SCHMALENBACH, K. ‘Article 2. Use of Terms’ in Oliver Dörr, Kirsten Schmalenbach (eds) Vienna Convention on the Law of Treaties A Commentary (2nd ed) (Springer 2018) p. 32; HOLLIS, D. B. ‘Defining Treaties’ in Duncan B Hollis (ed), The Oxford Guide to Treaties (2 nd ed OUP, Oxford 2020) pp. 12–13. 39 UNGA Res 2166 (XXI) (5 December 1966), preambular recital 2.

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