8 does not mean that the Court cannot take into account acts that this Convention classifies as genocide, as aggravating circumstances of violations of the rights protected by the American Convention on Human Rights (with a direct effect on the determination of reparations). To this end, it is not necessary for these acts to be classified as genocide, which could give rise to difficulties in applying the provisions of the American Convention, whose purpose is to determine the international responsibility of the State and not of the individual. 25. Nevertheless, I do not consider these difficulties to be insurmountable. Under the American Convention it is perfectly possible to determine the aggravated international responsibility of the State, with all the juridical consequences for reparations. These include compliance with the State’s obligation to determine the individual criminal responsibility of the perpetrators of the violations of the protected rights, and their corresponding punishment. This is not the first time that the InterAmerican Court identifies aggravated international responsibility (in the terms of paragraph 51 of this judgment in the Case of Plan de Sánchez Massacre). In its preceding judgment of November 25, 2003, in Case of Myrna Mack Chang v. Guatemala, the Court concluded that, from the proven facts, an “aggravated international responsibility of the respondent State” was evident (para. 139). 26. Norms embodied in treaties and conventions may perfectly well be evidence of customary international law.28 Further still, they may subsist as norms of both treaty-based and customary international law.29 The 1948 Convention on Genocide codified the matter in question. Even if it is considered – a view I do not share – that it was only after the adoption of that Convention that the prohibition of genocide gradually came to incorporate contemporary international law (following its embodiment in international treaty-based law), it cannot be denied that, when the facts of the instant case occurred, the prohibition of genocide was already part of international customary law and, even, of jus cogens.30 27. Here we are truly entering the domain of jus cogens and of aggravated international responsibility. I have already described in detail the juridical consequences of the latter in my above-mentioned separate opinion (paras. 41 to 55) to the Case of Myrna Mack Chang (2003), which I refer to here. In my opinion, the interpretation and application of the American Convention does not exclude the interpretation and application of general international law; to the contrary, it requires this. 28 R.R. Baxter, "Treaties and Custom", 129 Recueil des Cours de l'Académie de Droit International de La Haye (1970) pp. 31, 43, 57 and 102-103. 29 Remember, for example, the principle of pacta sunt servanda – to which the two Vienna Conventions on the Law of Treaties refer (Article 26 and preamble), - which emerged as a general rule for the interpretation of treaties and of international customary law. Thus, this principle is deeply rooted in the corpus juris of international law as a whole; M. Lachs, "Pacta Sunt Servanda", in Encyclopedia of Public International Law (ed. R. Bernhardt), vol. 7, Amsterdam, North-Holland/Max Planck Institute, 1984, pp. 364-371. The basic issue of the validity of the norms of international law transcends the sphere of the law of treaties. Perhaps, in the last analysis, the basis of an international obligation is of a meta-juridical nature; J.L. Brierly, The Basis of Obligation in International Law, Oxford, Clarendon Press, 1958, p. 65; J.L. Brierly, The Law of Nations, 6a. ed., Oxford, Clarendon Press, 1963, p. 54. 30 Cf., in this respect, for example, W.A. Schabas, Genocide in International Law, Cambridge, University Press, 2002 [reprint], pp. 445 and 500-501, and cf. pp. 434-435; and, regarding the prohibition of genocide as being established by general or customary international law, cf. ibid., pp. 99, 142, 362, 365 and 548; and cf. also ibid., pp. 168 and 209, on the events in Guatemala.