25 would dare to deny the objective illegality of acts of genocide 93, of systematic practices of torture, of summary and extra-legal executions, and of forced disappearance of persons, - practices which represent crimes against humanity, - condemned by the universal juridical conscience 94, parallel to the application of treaties. Already in its Advisory Opinion of 1951 on the Reservations to the Convention against Genocide, the International Court of Justice pointed out that the humanitarian principles underlying that Convention were recognizedly `binding on States, even without any conventional obligation'. (...) In sum and conclusion on the point under examination, the emergence and assertion of jus cogens evoke the notions of international public order and of a hierarchy of legal norms, as well as the prevalence of the jus necessarium over the jus voluntarium; jus cogens presents itself as the juridical expression of the very international community as a whole, which, at last, takes conscience of itself, and of the fundamental principles and values which guide it"95. 89. In the same line of reasoning, in my Separate Opinion in the case of the Massacre of Plan de Sánchez case, concerning Guatemala (Judgment of 29.04.2004), I saw it fit to insist on the point that "The concept itself of jus cogens, in my understanding, transcends the ambit of both the law of treaties 96 and the law on the international responsibility of the States 97, so as to encompass general international law and the very foundations of the international legal order" 98. 90. And in my Separate Opinion in the Tibi versus Ecuador case (Judgment of 07.09.2004), I allowed myself to add that jus cogens, besides its horizontal dimension whereby it has a bearing upon the very foundations of international law, also expands itself in "a vertical dimension, of the interaction of the international and national legal orders in the present domain of protection. The effect of jus cogens, in this second (vertical) plane, is in the sense of invalidating every and any legislative, administrative or judicial measure which, at the level of the domestic law of the States, attempts to authorize or tolerate torture" (par. 32). 93 . In its Judgment of 11 July 1996, in the case concerning the Application of the Convention against Genocide, the International Court of Justice affirmed that the rights and obligations set forth in that Convention were "rights and duties erga omnes"; ICJ Reports (1996) p. 616, par. 31. 94 . Inter-American Court of Human Rights, case Blake versus Guatemala (Merits), Judgment of 24.01.1998, Separate Opinion of Judge A.A. Cançado Trindade, par. 25, and cf. pars. 23-24. 95 . Paragraphs 66, 68, 71 and 73, respectively, of my Concurring Opinion. 96 . Its formulation in the two Vienna Conventions on the Law of Treaties (1969 and 1986), Articles 53 and 64. 97 . E.g., its recognition in the Articles on the Responsibility of States, adopted by the U.N. International Law Commission in 2001. 98 . Paragraph 29, and cf. also pars. 32-33 of my Separate Opinion.