-10Commission has the principal responsibility for interpreting the time limits that it has established.3 45. The representatives requested the Court to reject this objection for the reasons set out by the Commission and also alleged, inter alia, that: (a) Once the admissibility of a petition has been determined and the Commission has taken a decision on the exhaustion of domestic remedies, in principle, the Court should abide by the Commission’s decision, in application of the principle of procedural estoppel, for reasons of legal certainty and procedural economy; (b) The State has not proved that there was any irregularity in the proceedings before the Commission that could have affected its right to a defense; to the contrary, it was able to submit its arguments in an opportune manner; (c) The State raised the objection that the Commission has too hastily qualified the proceedings before ordinary justice as ineffective; however, the time elapsed between the moment when the facts occurred and the date of the Tribunal Nacional's judgment (1990-1997) clearly exceeded the limits of reasonableness considered in the Court’s case law.4 46. Subsequently, during the oral arguments made during the public hearing held on September 19 and 20, 2005, the State declared that: With regard to [the preliminary objections raised], the State wishes to request the Court to joinder the reasons described in these objections to the issue of merits. […] In other words, […] we are invoking the full competence of the Court to decide on this point concerning admissibility requirements. 47. Following the public hearing, the Commission and the representatives again submitted written observations on the preliminary objections and the State’s subsequent request concerning the joinder (supra para. 33). In its final written arguments, the State did not make any reference to the objections, or to its request for joinder. 48. With regard to the statement made by the State during the public hearing, particularly the fact that Colombia expressly accepted the Court’s jurisdiction to hear this case, the Court understands that Colombia withdrew the preliminary objection as such. In other words, the Court must now consider whether the State’s request to “joinder” the arguments submitted initially as preliminary objections with the merits of the case is admissible. 49. Regarding the so-called “first grounds” for the preliminary objection filed by the State, the Court observes that these arguments are clearly related to the alleged violation of the rights to a fair trial and to judicial protection, which constitutes a central element of the dispute in this case. Since these arguments are no longer of the nature of a preliminary objection, the Court will examine the parties' arguments 3 Cf. brief with observations of the Inter-American Commission on the preliminary objections filed by the State (merits file, tome II, folios 418 to 426). 4 Cf. brief with observations of the representatives on the preliminary objections filed by the State (merits file, tome II, folios 438 to 451).