Bilateral Investment Treaties from the perspective of the Vienna Convention on the Law of treaties : a path towards the "defragmentation" of International Law

Los Tratados Bilaterales de Inversión desde la perspectiva de la Convención de Viena de Derecho de los tratados : un camino hacia la “defragmentación” del Derecho Internacional

The Vienna Convention on the Law of Treaties proposes the mechanism agreed by the States for the interpretation of international treaties. The denominated Bilateral Investment Treaties (BITs) are a specific example of the International Investment Law. Nevertheless. within this branch of International Law doubts about its correspondence with the application of the “treaty of treaties” still persist and encouraged by the trend mainly promoted by the “practitioners”, arbitrators or representatives of the parties, the way in which different treaties on investment matters have been construed expose the tensions of a fragmented International Law. Who has to interpret them? Under which rules? This article proposes, firstly, to tackle the genesis and evolution of the International Investment Law; secondly, its characterization as an example of the sustantive fragmentation of International Law, in order to address thirdly the interpretation according to the rules of the Vienna Convention on the Law of Treaties between States as a tool to solve the dilemma described. The conclusion follows the last point, understanding this instrument as the only one among the General International Law that advocates for a harmonious interpretation and a systematic integration. Consequently, it would provide an increasing legal certainty -a favorable scenario for investors- and a greater respect for the will of the States that created the international norms in dispute.