conviction, only Art [icle] 84 of the Argentine Criminal Code, which was in full force at the moment [of the facts]”. According to the State, the mention of the provisions contained in Decree No. 692-92 “is absolutely incidental and non-essential in the development of the legal argument presented”, as “they are not part of the operative part of the ruling.” It argued that the Court that convicted Mr. Mohamed found him criminally responsible for the offense of manslaughter, “expressly referring to [Article 84] of the [Argentine] Criminal Code as the legal source for the conviction,” and to the standards of international practice on the matter. B) Considerations of the Court 131. The principle of legality constitutes one of the central elements of criminal prosecution in a democratic society by establishing that “no one may be convicted of any act or omission that did not constitute a criminal offense, under the applicable law, at the time it was committed.” This principle governs the conduct of all State bodies, in their respective spheres of competence, and particularly with regard to the exercise of the punitive power.104 In a democratic State governed by the Rule of Law, it is essential to strengthen precautions to ensure that punitive measures are adopted with absolute respect for the basic rights of the individual and with prior careful verification of whether or not unlawful behavior exists.105 132. Likewise, the Court has held that the definition of an act as unlawful and the determination of its legal effects must precede the conduct of the person considered an offender. Otherwise, individuals would not be able to guide their behavior according to a valid and certain legal system that articulates social censure and its consequences.106 The Court has also indicated that the principle of non-retroactivity is designed to prevent a person from being penalized for an action that was not a punishable or prosecutable offense at the time when it was committed.107 133. The Court has emphasized that, when applying criminal law, the judge is obliged to adhere strictly to its provisions and observe the greatest rigor to ensure that the conduct of the defendant corresponds to a specific category of crime, so that he does not punish acts that are not punishable by law.108 The Court considers it necessary to add that, in dealing with an offense of negligence, whose unlawfulness is minor compared with that of intentional crimes and whose typical elements are defined in a generic manner, the judge or court is required to observe the principle of legality when ascertaining the effective existence of the defined conduct and determining criminal responsibility. 134. The Court does not share the view of the Commission and the representatives that the decision by the First Chamber of the National Chamber of Appeals, on July 4, 1995 (supra para. 54), to declare inadmissible the special federal appeal changed the grounds of the conviction, thereby constituting a “new source of charges.” The Court 104 Cf. Case of Baena Ricardo et al. v. Panama. Merits, Reparations and Costs, para. 107, and Case of Fermín Ramírez V. Guatemala. Merits, Reparations and Costs, para. 90. 105 Cf. Case of Baena Ricardo et al. v. Panama. Merits, Reparations and Costs, para. 106, and Case of De La Cruz Flores V. Peru. Merits, Reparations and Costs. Judgment of November 18, 2004. Series C No. 115, para. 81. 106 Cf. Case of Baena Ricardo et al. v. Panama. Merits, Reparations and Costs, para. 106, and Case of de la Cruz Flores v. Peru. Merits, Reparations and Costs, para. 104. 107 Cf. Case of Ricardo Canese v. Paraguay. Merits, Reparations and Costs. Judgment of August 31, 2004. Series C No. 111, para. 175, and Case of García Asto and Ramírez Rojas v. Peru. Preliminary Objection, Merits, Reparations and Costs. Judgment of November 25, 2005. Series C No. 137, para. 191. 108 Cf. Case of Ricardo Canese v. Paraguay. Merits, Reparations and Costs, para. 82, and Case of Fermín Ramírez v. Guatemala. Merits, Reparations and Costs, para. 90. 37