Resumen de Treaty Interpretation by the Inter-American Court of Human Rights: Expansionism at the Service of the Unity of International Law

Lucas Lixinski

• The article examines the jurisprudence of the Inter-American Court of Human Rights in several areas of adjudication which initially did not fall under the instrument, such as environmental rights, international humanitarian law, and investors� rights. In all these areas, the Court has used instruments �foreign� to the Inter-American system as a means to expand the content of rights in the American Convention. As a result, the umbrella of protection of this instrument, and the reach of the Court, is far greater than originally envisaged. After analysing the specific provision on interpretation of the American Convention on Human Rights as compared to the equivalent mechanisms in the Vienna Convention on the Law of Treaties, the article analyses several case studies of expansionism in the case law of the Court, asking throughout the analysis the question whether this helps the unity or the fragmentation of international law. The article argues that this exercise in expansionism, albeit imperfect, eventually contributes to the unity of international law. In this sense, this expansionism happens within controlled boundaries, and the use of external instruments is more of a validation of findings the Court could make based solely on the Inter-American instruments, rarely creating new rights.