7 Cogent reasons militate in favour of conferring upon the international supervisory organs established by those treaties the determination of the compatibility or not 19 of reservations with the object and purpose of human rights treaties , - instead of leaving such determination to the States Parties themselves, as if they were, or could be, the final arbiters of the scope of their conventional obligations. That system of international control would be much more in keeping with the special character of human rights treaties, endowed with mechanisms of supervision of their own. Here, in effect, two necessarily complementary elements are added: the special character of human rights treaties (a determining factor, which cannot be minimized), and the necessity of determination of the scope of the 20 competences of the supervisory organs created by them . 20. The same kind of concern applies to the denunciation of a treaty, 21 permissible only when expressly foreseen in this latter , and not to be presumed 22 in the present domain of protection . Here, again, the time factor marks its 18. The human rights international supervisory organs begin to disclose their preparedness to proceed in this way. In its judgments in the Belilos (1988) and Weber (1990) cases, for example, the European Court of Human Rights considered invalid the declarations amounting to reservations of Switzerland to the European Convention on Human Rights. In the Belilos case, locus classicus on the question, the Court considered that reservation, of a general character, incompatible with the object and purpose of the European Convention (in the light of its Article 64). The Inter-American Court of Human Rights, in its third Advisory Opinion (1983), warned that the question of reciprocity pertaining to reservations did not apply fully in relation to human rights treaties (paragraphs 62-63 and 65). And the Human Rights Committee, under the United Nations Covenant on Civil and Political Rights, in its general comment n. 24(52), of November 1994, also warned that the provisions of the two Vienna Conventions and the classic rules on reservations (based on reciprocity) are not appropiate to human rights treaties; the system of objections by States to reservations, in particular, did not make much sense, as States often have no interest or necessity to object to reservations, and the consequent absence of protest could not imply that a reservation would be compatible or not with the object and purpose of a given human rights treaty (paragraph 17). The two regional Courts of human rights have pronounced on the matter (supra) despite the fact that neither the European Convention on Human Rights (Article 64), nor the American Convention on Human Rights (Article 75 of which limits itself to make a renvoi to the pertinent provisions of the Vienna Convention on the Law of Treaties of 1969), confer expressly this function upon them. This is, notwithstanding, a question of common sense, if not of functional necessity. 19. The scope of such competences could, in this respect, be given precision expressly in the instruments of protection themselves to be adopted in the future; meanwhile, it is the case-law of the human rights international supervisory organs that will care to affirm their competence on the matter and to overcome the inadequacy and the insufficiencies of the system of reservations currently set forth in the two Vienna Conventions on the Law of Treaties. 20. The only exceptions to this principle contemplated in the two Vienna Conventions on the Law of Treaties (Article 56) are when it is established that it was the intention of the parties to admit the possibility of denunciation, and when this latter can be inferred from the nature of the treaty. 21. The American Convention on Human Rights contains a clause of denunciation (Article 78), the content of which reveals the concern of the draftsmen in the sense that, even in the extreme case of its application, the requisites established therein were to be rigorously observed. The United Nations Covenant on Civil and Political Rights, in its turn, does not provide for denunciation; in this respect, the Human Rights Committee, operating