do not indicate what the legitimate purposes or objectives of an intervention in their respective spheres of protection would be, not even as a guiding principle.59 In Advisory Opinion OC-04/84, which assesses a proposed amendment to the Constitution of Costa Rica related to naturalization, the Court indicated that differences in treatment “may not be unjust or unreasonable; that is, they may not be arbitrary, capricious, despotic or in conflict with the essential oneness and dignity of humankind.”60 45. On this basis, I have therefore verified that the objectives sought by the professional restriction based on national origin are the following: (i) protection of State sovereignty; (ii) promotion of legal certainty and security, and (iii) protection of human rights. Such objectives are characterized, in the abstract, as legitimate, so that this second requirement is also met.61 46. The principle of proportionality62 signifies that, once the sphere of protection of a specific right has been breached, the intervention can only be considered proportionate if it satisfies the criteria of strict appropriateness (or suitability), necessity and proportionality.63 The first requirement calls for the analysis of whether the differentiating measure is suitable: that is, whether it pursues a legitimate and essential objective pursuant to the Convention.64 The second requirement calls for the measure to be necessary to achieve that objective; that is, it cannot be substituted by a less harmful measure,65 in other words by a restrictive measure that is less harmful for the holder of the rights, but one that is able to achieve the objective pursued by the legislator. The idea that underlies necessity or enforceability is that freedoms are the rule; therefore, they should only be restricted insofar as essential to protect other human rights or as strictly required to promote an objective of general interest. Lastly, we have the proportionality test, stricto sensu, according to which the benefits of the adoption of the measure analyzed must clearly exceed the sacrifices imposed by the restriction of the treaty-based rights concerned.66 In this section, I will address the criteria sequentially.67 1. Suitability Cf. MÜLLER, Friedrich. Discours de la Méthode Juridique. Trad. Olivier Jouanjan. Paris: Presses Universitaires de France, 1996, p. 372 and ff. 59 Cf. Proposed Amendments to the Naturalization Provisions of the Constitution of Costa Rica, Advisory Opinion OC-4/84, January 19, 1984. Series A No. 4, para. 57; Juridical Status and Human Rights of the Child, Advisory Opinion OC-17/02, August 28, 2002. Series A No. 17, para. 57. 60 61 Cf. Answering brief of June 14, 2021, para. 227. Cf. Case of Álvarez Ramos v. Venezuela. Preliminary objection, merits, reparations and costs. Judgment of August 30, 2019. Series C No. 380, para. 104-110; Case of Palamara Iribarne v. Chile. Merits, reparations and costs. Judgment of November 22, 2005. Series C No. 135, para. 79; Case of Lagos del Campo v. Peru. Preliminary objections, merits, reparations and costs. Judgment of August 31, 2017. Series C No. 340, para. 102. 62 Cf. Case of Valencia Campos et al. v. Bolivia. Preliminary objection, merits, reparations and costs. Judgment of October 18, 2022. Series C No. 469. Separate opinion of Judge Nancy Hernández López and Judge Rodrigo Mudrovitsch, para. 43. 63 64 Cf. Case of I.V. v. Bolivia. Preliminary objections, merits, reparations and costs. Judgment of November 30, 2016. Series C No. 329, para. 241; Case of Valencia Campos et al. v. Bolivia. Preliminary objection, merits, reparations and costs. Judgment of October 18, 2022. Series C No. 469. Separate opinion of Judge Nancy Hernández López and Judge Rodrigo Mudrovitsch, para. 43. 65 Cf. Case of I.V. v. Bolivia. Preliminary objections, merits, reparations and costs. Judgment of November 30, 2016. Series C No. 329, para. 241; Case of Valencia Campos et al. v. Bolivia. Preliminary objection, merits, reparations and costs. Judgment of October 18, 2022. Series C No. 469. Separate opinion of Judge Nancy Hernández López and Judge Rodrigo Mudrovitsch, para. 43. 66 Cf. Case of I.V. v. Bolivia. Preliminary objections, merits, reparations and costs. Judgment of November 30, 2016. Series C No. 329, para. 241; Case of Valencia Campos et al. v. Bolivia. Preliminary objection, merits, reparations and costs. Judgment of October 18, 2022. Series C No. 469. Separate opinion of Judge Nancy Hernández López and Judge Rodrigo Mudrovitsch, para. 43. 67 Regarding the criteria examined, I note that there are differences in the terminology used in the Court’s case law, in the application of these standards by other international courts, and in legal doctrine. Consequently, I find it essential to examine them based on the substance of each matter, over and above questions of nomenclature. 12