- 11 - proved the existence of an error and had not been able to indicate the specific prejudice suffered. The Commission emphasized that the State’s arguments on the principle of complementarity were related to the merits stage and the stage of transition prior to the case being submitted to the Court. In addition, it underlined that, over and above whether Mexico considered the extensions to be very brief, it had been given the opportunity to report substantive and concrete progress in relation to all the recommendations, and “the very act of continuing to grant extensions to the State signified an assessment of the information provided by Mexico in its periodic reports.” The Commission also indicated that “the reasons why, after granting four extensions, the Commission decided to submit the case to the Inter-American Court, are clearly indicated in the submission note of September 17, 2016.” Consequently, it asked the Court to reject the preliminary objection filed by the State. 20. The representatives argued that the Commission “had not committed any error, because it assessed the State’s non-compliance and acted within its terms of reference” and “the State failed to prove that the [Commission’s] actions prejudiced its right of defense.” In particular, they indicated that the preliminary objection was ‘based precisely on the Mexican State’s discrepancy with the [Commission’s] assessment of the failure to comply with the recommendations made in the Merits Report” and that a difference of opinion did “not prove that there had been an error of any kind in the [Commission’s] actions.” Thus, they alleged that, in essence, the State was requesting a control of legality with declarative effects, which was inadmissible pursuant to the Court’s case law. They also alleged that “the Commission had ruled clearly in both the Merits Report and in the note submitting the case that the proceedings underway did not comply with the obligation to clarify and punish the facts, and that the State had not taken any significant steps to comply with this item in the nine-month period between the notification of the Merits Report and the submission of the case to the Court.” B. Considerations of the Court 21. The Court, interpreting Article 42 of its Rules of Procedure, which regulates preliminary objections, considers that such objections are so called precisely because they are of a preliminary nature and, therefore, tend to prevent the analysis of the merits of the matter in dispute, by objecting to the admissibility of a case or to the Court’s jurisdiction to hear a specific case or any of its aspects, based on either the person, matter, time or place, provided that the issues are of a preliminary nature. 25 If it is not possible to consider the issues without a prior analysis of the merits of a case, they cannot be analyzed by means of a preliminary objection.26 22. In this case, the Court notes that the State has argued that the Commission committed a serious error that affected its right of defense, because it allegedly failed to assess or give fair consideration to the information provided during the procedure before that organ on the actions undertaken by the State, before and after the issue of the Merits Report, in relation to the investigation of the facts of this case and other forms of reparation. 23. In this regard, the Court recalls that when a party justifies that a serious error has been committed that violates its right of defense, the Court is authorized to execute a control of the Cf. Case of Las Palmeras v. Colombia. Preliminary objections. Judgment of February 4, 2000. Series C No. 67, para. 34, and Case of the Xucuru Indigenous People and its members v. Brazil. Preliminary objections, merits, reparations and costs. Judgment of February 5, 2018. Series C No. 346, para. 20. 25 Cf. Case of Castañeda Gutman v. United Mexican States. Preliminary objections, merits, reparations and costs. Judgment of August 6, 2008. Series C No. 184, para. 39, and Case of Herzog v. Brazil. Preliminary objections, merits, reparations and costs. Judgment of March 15, 2018. Series C No. 353, para. 80. 26