Most states in the Americas have unconditional jus soli regimes in accordance with the American Convention of Human Rights. Yet legal frameworks alone do not guarantee the prevention of statelessness in practice—or in legislation. The United Nations Human Rights Council stated in 2015 that “some countries in the Americas … have legislation that may be regarded as not fully in line with applicable international standards.”59 Even in countries were the legal frameworks comply with international standards, practical restrictions in the access to birth registration can restrict nationality rights. Case Law from the Inter-American Court of Human Rights In 1984, the Inter-American Court of Human Rights interpreted the scope of Article 20 of the ACHR. Advisory Opinion No. 4, requested by Costa Rica, reviewed a set of amendments to the Costa Rican Constitution. The court described the right to nationality as recognized in Article 20 as comprised of two characteristics: first, it “provides the individual with a minimal measure of legal protection in international relations through the link his nationality establishes between him and the state in question; and second, the protection therein accorded the individual against the arbitrary deprivation of his nationality, without which he would be deprived for all practice purposes of all of his political rights as well as of those civil rights that are tied to the nationality of the individual.”60 The court deemed the proposed amendments to be in compliance with these principles, in spite of the fact that they tightened naturalization rights.61 It emphasized that because the changes were not retroactive, they did not constitute arbitrary deprivation of nationality. Even though advisory opinions are not judgments, and accordingly do not have the same binding nature, they are a valuable source of law in which the court interprets the scope of the ACHR. For example, the court’s 1999 decision in Castillo Petruzzi v. Peru built on Advisory Opinion No. 4. In that case, Peru tried four Chilean nationals, alleged members of terrorist groups, for treason. The court underscored that international law imposes certain limits on the power states have over nationality, which is now “perceived as involving the jurisdiction of the state as well as human rights issues.”62 The court did not consider Peru to have violated Article 20 of the convention because their Chilean nationality was never questioned. The court was not persuaded by the petitioners’ argument that Peru had arbitrarily imposed on them and attempted to create an artificial bond of allegiance and loyalty to Peru. 63 Considering that Peru used the term treason according to the legal definition in its own criminal law, the court held that charging the petitioners with treason did not amount to ascribing to them the duties of Peruvian nationality.64 32 REGIONAL CONTEXT