6 of individuals, or for them to be its beneficiaries and even have recourse to the Court in defense of their rights.32 Nevertheless, the Convention continues to be a treaty. 33 13. Similarly, the view outlined in this opinion concerns one of the peculiarities of public international law that still exists - though to a lesser extent than in the past, but probably to a greater extent that one would wish - namely, the sphere of the internal, domestic, or exclusive jurisdiction of the States.34 This is also known as a margin of appreciation,35 or more simply as sovereignty, which demonstrates or implies that not everything is regulated by public international law. However, this situation does not constitute a defect or an imperfection in the international legal order, but responds to the type of society that it regulates or seeks to regulate. For this reason, in order to understand public international law it is essential to consider, albeit in general terms, the type of society that it seeks to govern. Such a society is characterized by States that basically recognize each other as sovereign and that consequently do not have executive, legislative and judicial branches that are centralized and hierarchical; States that cannot be judged without their consent, where there is no monopoly on the use of force, where the power structure is de facto and, therefore, changes only according to political factors and there is no hierarchy among the norms, only, at the most, a preference in their application. 14. It is in that context, then, that the inter-American System of Human Rights36 is inserted and must be understood. Within that system the main function of the Commission is “to promote respect for and defense of human rights,” 37 while the Court, in relation to its contentious jurisdiction, is Article 40 of the Court’s Rules of Procedure: “Brief containing Pleadings, Motions, and Evidence. 1. Upon notice of the presentation of the case to the alleged victim or his or her representatives, these shall have a non-renewable term of two months as of receipt of that brief and its annexes to autonomously submit to the Court the brief containing pleadings, motions, and evidence. 2. The brief containing pleadings, motions, and evidence shall contain: a. a description of the facts within the factual framework established in the presentation of the case by the Commission; b. the evidence offered, properly organized, with an indication of the alleged facts and arguments that it relates to; c. the identities of declarants and the object of their statements. Expert witnesses must also submit their curricula vitae and contact information; d. all claims, including those relating to reparations and costs.” 32 Article 2 a) of the Vienna Convention: “Use of terms. 1. For the purposes of the present Convention: “treaty” means an international agreement concluded between States in written form and governed by international law, whether embodied in a single instrument or in two or more related instruments and whatever its particular designation.” 33 “The question of whether a certain matter is or is not solely within the jurisdiction of a State is an essentially relative question; it depends upon the development of international relations. Thus, in the present state of international law, questions of nationality are, in the opinion of the Court, in principle within the reserved domain.” Permanent Court of International Justice, Advisory Opinion on Nationality Decrees Issued in Tunis and Morocco, Series B Nº 4 Page 24. 34 Protocol No. 15 amending the Convention for the Protection of Human Rights and Fundamental Freedoms, Article 1: “At the end of the preamble to the Convention, a new recital shall be added, which shall read as follows: “Affirming that the High Contracting Parties, in accordance with the principle of subsidiarity, have the primary responsibility to secure the rights and freedoms defined in this Convention and the Protocols thereto, and that in doing so they enjoy a margin of appreciation, subject to the supervisory jurisdiction of the European Court of Human Rights established by this Convention.” 35 36 Footnote 17. Article 41: “The main function of the Commission shall be to promote respect for and defense of human rights. In the exercise of its mandate, it shall have the following functions and powers: a) to develop an awareness of human rights among the peoples of America; b) to make recommendations to the governments of the member states, when it considers such action advisable, for the adoption of progressive measures in favor of human rights within the framework of their domestic law and constitutional provisions as well as appropriate measures to further the observance of those rights; 37 c) to prepare such studies or reports as it considers advisable in the performance of its duties;