CYIL vol. 9 (2018)

MARTIN FAIX – ONDŘEJ SVAČEK CYIL 9 ȍ2018Ȏ a transfer of exclusive competence to the international organization with the consequence the Security Council replacing the member States? Second ‘difficult question’ is the identification of international organizations the practice of which would be relevant. Apparently not only actors other than States and international organizations shall be excluded from the possibility to contribute to customary international law, 31 but according to Wood the practice of only some of international organizations’ organs is to be considered relevant, namely those in which persons represent States and are not serving in their personal capacity as experts. As a third issue Wood distinguishes between practice relating internal affairs of organizations and external practice, i.e. practice related to States and other international organizations, of which only the latter shall be relevant. Another issue reflecting specificities of international organizations is the fact that they may contribute primarily to those rules of international law by which they themselves are (or would be) bound. Finally the questions arise whether ultra vires acts of international organizations constitute a relevant practice as well and what role plays inaction or silence of international organizations. The questions raised by Wood would require more detailed analysis, which goes beyond the scope of this contribution. Nevertheless, the questions raised are certainly of importance. If accepting ILC’s conclusions (and Wood’s explanations), then for example a pronouncement such as that of NATO SG (on triggering Article 5 in reaction to cyber-attack) would constitute practice not less relevant than that of its member States concerning the right of self-defence. 4. Role of practice in the norm-generating process of international customary law Besides questions arising with regard to both, conventional and customary rules, in the context of customary law practice plays crucial role in the norm-generating process. 32 This opens traditional question concerning creation of customary international law. The possibilities are twofold: a) deductive (value-based) approach 33 which is perspective, it does not look back, it is based on emerging values and interests which were considered only insufficiently in the pre- existing legal balance, it does not necessarily require a consistent pattern of previous practice; b) inductive – traditional method which is based on assumption that to determine the existence and content of a rule of customary international law, it is necessary to ascertain whether there is a general practice that is accepted as law ( opinio juris ). The latter approach is widely accepted both in the practice of the ICJ 34 and the ILC. 35 31 Ibid . 32 An attempt of the ICJ to relax the two constituent elements, or at least their evidence, as regards certain customary rules because of their importance for the co-existence and vital co-operation between States, is disputable. Cf. Case concerning Delimitation of the Maritime Boundary in the Gulf of Maine Area (Canada v. United States of America), Judgment, I.C.J. Reports 1984. For discussion of this idea cf. TREVES, Tullio. Customary International Law. In: The Max Planck Encyclopedia of Public International Law . Available at: www. opil.ouplaw.com [2018-07-07]. 33 CANNIZZARO, E.: Customary International Law on the Use of Force: Inductive Approach v. Value-Oriented Approach. In: CANNIZZARO, E., PALCHETTI, P.: Customary International Law on the Use of Force: Methodological Approach . Brill: Leiden, 2005, p. 248. 34 Military and Paramilitary Activities in and against Nicaragua (Nicaragua v. United States of America) . Merits, Judgment, I.C.J. Reports 1986, p. 109, para. 207. The most explicit stipulation can be found in the judgment rendered in the Gulf of Maine case (para. 111), where the ICJ ruled that presence of customary rules “can be tested by induction based on the analysis of a sufficiently extensive and convincing practice, and not by deduction from preconceived ideas”. 35 ILC, A/71/10, p. 84.

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