4. In virtue of the definitive and non-appealable nature of the Court's Judgments, according to the provisions of Article 67 of the American Convention, the State should fully comply with such Judgments. 5. The obligation to comply with the Tribunal's rulings conforms to a basic principle of international responsibility of the State, supported by international jurisprudence, under which States must abide by their international treaty obligations in good faith (pacta sunt servanda) and, as set forth by this Court and in Article 27 of the Vienna Convention on the Law of Treaties of 1969, States cannot, for domestic reasons, ignore their international responsibility.2 The treaty obligations of State Parties are binding on all branches and bodies of the State.3 6. The States Parties to the Convention must ensure compliance with its conventional provisions and their effectiveness (effet utile) within their respective domestic legal systems. This principle applies not only to the substantive provisions of human rights treaties (i.e., those addressing protected rights), but also to procedural provisions, such as those concerning compliance with the Court’s decisions. These obligations should be interpreted and enforced in such a manner that the protected guarantee is truly practical and effective, bearing in mind the special nature of human rights treaties.4 A. Obligation to investigate the facts of the case (Operative Paragraph 8 of the Judgment) 7. The State reported on various measures undertaken as of March 22, 2010 in preliminary inquiry SIEDF/CGI/454/2007, which is overseen by the Attorney General’s Office and seeks information on what happened to Mr. Rosendo Radilla Pacheco. The State reported that “various meetings [...] were held in order to develop a work plan with the victims’ next of kin […] for the purpose of continuing with investigations[.]” Additionally, the State indicated that “Tita Radilla Martínez’s legal representatives […] have had full access to the investigation[’s files] every time they have requested it.” 8. The representatives indicated that “to date, no military or civilian authority with power over the Armed Forces that were active at the time of [Mr.] Radilla [Pacheco]’s disappearance has been called to give a statement.” They also affirmed that none of the actions that the Attorney General’s Office has carried out “has been directed toward [military and civilian] officials who were employed at the time that [Mr.] Radilla [Pacheco] was detained/disappeared.” According to the representatives, the only “relevant [measures] carried out that are vaguely linked to the Armed Forces [are] those related to the 2 Cf. International responsibility for the issuance and application of laws that violate the Convention (Art. 1 and 2 of the American Convention on Human Rights). Advisory Opinion AO-14/94 of December 9, 1994. Series A No. 14, para. 35; Case of the Miguel Castro Castro Prison v. Peru. Monitoring Compliance with Judgment. Order of the Inter-American Court of Human Rights of December 21, 2010, Considering Clause 6, and Case of Tibi v. Ecuador. Monitoring Compliance with Judgment, supra note 1, Considering Clause 3. Cf. Case of Castillo Petruzzi et al. v. Peru. Monitoring Compliance with Judgment. Order of the InterAmerican Court of Human Rights of November 17, 1999, Considering Clause 3; Case of the Miguel Castro Castro Prison v. Peru, supra note 2, Considering Clause 6, and Case of Tibi v. Ecuador. Monitoring Compliance with Judgment, supra note 1, Considering Clause 4. 3 Cf. Case of Ivcher Bronstein v. Peru. Competence. Judgement of the Inter-American Court of Human Rights of September 24, 1999. Series C No. 54, para. 37; Case of the Miguel Castro Castro Prison v. Peru, supra note 2, Considering Clause 7, and Case of Tibi v. Ecuador. Monitoring Compliance with Judgment, supra note 1, Considering Clause 5. 4 3