Más allá del efecto y de la intención: la proporcionalidad en los arbitrajes de inversiones.

Indirect expropriation is the prevailing form of expropriation today, and its determination constitutes one of the main problems in international investment law. Doctrine and case-law has identified two possible solutions centered, respectively, in the effects or in the intention of the measures adopted by the host state. Of late, a third alternative has appeared that finds possible support in certain last-generation investment treaties. Deriving from the case-law of the European Court of Human Rights on the protection of property, it applies the principle of proportionality to determine the expropriatory nature of those measures judicially challenged by foreign investors in international arbitrations. This possible solution, however, also presents some issues of implementation. The purpose of this work is to study the application of proportionality in these disputes. Through the analysis of the relevant case-law, and the use of the dogmatic and comparative methods, the present article examines the emergence of this principle in international investment law, highlighting the differences in its application in the fora in which it has been used, to conclude that in order to become a useful instrument for solving claims of indirect expropriation it must have a clear normative basis, allowing for its employment, in tandem with the margin of appreciation, to determine the lawfulness of the respective measures, not their expropriatory nature. [ABSTRACT FROM AUTHOR]