CYIL vol. 14 (2023)

PETRA RUFFER LUSTIGOVÁ CYIL 14 (2023) and it is clear that “ mere allegations that a particular government supports terrorism ” 81 do not quite fulfil the original intentions of the Charter drafters during the San Francisco conference. And as Professor Gowlland-Debbas ironically added that “ this determination of a threat to international peace took place three years [sic] after the bombing ”. 82 4.2 Priority of Article 103 of the UN Charter over treaties and customary law Besides the legal limitations stemming from the institutional law of the United Nations, there is an equal need to analyse the provisions of general international law that could possibly have a restraining effect on the Security Council’s freedom to act. Here, referring to the origins of international law, we are faced with a “ rather complex trilateral relationship ” 83 between the UN institutional law (namely the Charter “ considered to represent the constitutional law of the international community ”) 84 on one side; customary rules on the other side; and a number of norms which may origin in, and be part of both these categories, and that are, due to their nature considered to be superior to them and making a separate category of peremptory norms of international law ( ius cogens ). Article 103 of the UN Charter explicitly mentions “ obligations under any other international agreement ” 85 (irrespective if entered into prior or subsequently to the adoption of the Charter); the question to answer here is whether the UN Charter provisions also prevail over the rules of customary international law. Article 103 doesn’t suggest what the relationship between the obligations of the United Nations and those which are rooted in customary international law could be, nor is there a united opinion on whether that provision even prevails over it. For example, S. Droubi maintains that it would be illogical to presume that the Charter prevails over treaties and not customary rules, given that they enjoy the same value as sources of international law, 86 and he further claims that Security Council “ resolutions override conflicting customary norms ”. 87 Accordingly, G. Oosthuizen concludes in his article that “ customary international law could be overridden by Security Council decision ”, 88 and indeed “ [i]t is without a doubt within the power of the Security Council to do just that ”. 89 This notion has been also confirmed by the most recent Report of the International Law Commission (2019), stating that while Article 103 “ speaks only of international agreements, it has been interpreted as applying to customary international law ” 90 as well. 91 81 KIRGIS, F. L. The Security Council First Fifty Years, 89 AJIL , 1995, p. 516. 82 GOWLLAND-DEBBAS, V. The Relationship between the International Court of Justice and the Security Council in the Light of the Lockerbie Case, 88 AJIL , 1994, p. 663. 83 Dupuy, supra note 40 , p. 7. 84 Gowlland-Debbas, supra note 2 , p. 93. 85 Article 103 of the UN Charter. 86 Droubi, supra note 58 , p. 5. This opinion is also supported by the fact that “even if two norms belonging to two sources of international law appear identical in content, and even [states] are bound by these rules both on the level of treaty-law and on that of customary international law, these norms retain a separate existence (North Sea Continental Shelf Case, 1986, para 178).” Dupuy, supra note 40 , p. 7. 87 Droubi, supra note 58 , p. 6. 88 Oosthuizen, supra note 66 , p. 558, note 35. 89 Oosthuizen, ibid. , p. 558. 90 Supra note 41, p. 189, note 857. 91 “It should be noted that one of the highly controversial issues raised by the Order of the Court in the Lockerbie Case is that it does not even consider the fact that the rule ’ aut dedere, aut judicare ’ embodied in the Montreal Convention (over which Resolution 748 prevails on the basis of Charter Article 103) is most probably at the same time a customary rule”. Dupuy, supra note 40 , p. 13, note 36.

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