CYIL vol. 8 (2017)

CYIL 8 ȍ2017Ȏ FAILURE TO REACT AS EVIDENCE OF OPINIO IURIS International Law (1992 edition) “acquiescence is a type of qualified inaction”; “the doctrine of acquiescence represents the proposition of binding effect resulting from passivity and inaction with respect to foreign claims which, according to the general practice of States … usually call for protest in order to assert, preserve or safeguard rights”. 5 With reference to the International Court of Justice Fisheries Case, the Encyclopedia mentions to “the point at which silence and toleration become ‚law-making‘ acquiescence – or in other words, the point at which international law requires protest or some other form of action in order to preserve legal positions” and observes that the Court in essence stressed, i.a ., the following prerequisites for a silence to acquire such status: “a general toleration of the claims by the international community and prolonged abstention from reaction, especially by States particularly interested, concerned and affected”. The Encyclopedia adds that “the law of acquiescence has arisen mainly in the context of territorial disputes concerning bilateral relations or local custom”. 6 After reading the above cited definition in the Encyclopedia, the legal significance of the failure to react as possible evidence of opinio iuris seems to be more nuanced. It appears that the context (circumstances) of the specific situation is an important factor for assessing the legal relevance of the failure to react as evidence of opinio iuris and that this context may take various, significantly different forms. The question is whether one general conclusion along the lines proposed in draft conclusion 10, paragraph 3 can appropriately encapsulate all these different contexts and whether, on the other hand, it cannot misrepresent the significance of the failure to act in some of these contexts. Let’s have a look, for example, at some propositions put forward by legal scholars with respect to the norms prohibiting the use of force in international law. In connection with recent United States airstrikes against Syria for the use of chemical weapons in April 2017 and French president Macron‘s related statement that the use of chemical weapons in Syria would cross a ”red line” for France and result in reprisals, one commentator refers to the fact that “[t]he vast majority of states that spoke about the U. S. operation supported or were non-committal about it … ” and that, in addition, ”[v]ery few states condemned it as unlawful” and suggests that this ”pattern of behavior of states” could have some effect on the application of the prohibition on the use of force contained in Article 2(4) of the United Nations Charter, since the states, in effect, ”declined to “acquiescence” is not used, but the Commission’s commentary refers to the words used in the judgment by the International Court of Justice of 2008 in the dispute between Malaysia and Singapore (”The absence of reaction may well amount to acquiescence … That is to say, silence may also speak, but only if the conduct of the other State calls for a response”); Sovereignty over Pedra Branca/Pulau Batu Puteh, Middle Rocks and South Ledge (Malaysia/Singapore) Judgment, I. C. J. Reports 2008, pp. 50-51, para. 121; cited in: ILC, Report of its sixty-eight session, op. cit. sub 3, p. 100, fn. 315). For further references to “acquiescence” see the Third report on identification of customary international law, by Michael Wood, Special Rapporteur, doc. A/CN.4/682, 27 March 2015, pp. 10-11, para. 21. 5 MÜLLER, J. P., COTTIER, T., Acquiescence, in: BERNHARDT, R. (ed.), Encyclopedia of Public International Law , Volume I (1992), p. 14. 6 Ibid ., pp. 14-15. See further SKUBISZEWSKI, K., “Elements of Custom and the Hague Court”, ZaöRV , 31 (1971), p. 846 (“The attitude of mere toleration, i.e. lack of protest linked to lack of express consent or acquiescence, is sufficient when the claims put forward by the participants in the practice do not impose any duties on the non-participants … But when a correlative duty follows from the right claimed in the practice, the attitude of non-participants – in order to contribute to the creation of custom – must be of a more explicit nature. That is, it must be either express consent or unequivocal acquiescence.”); cited in: Third report on identification of customary international law, op. cit. sub 4, p. 13, fn. 50.

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