System in progress: applicable law and the icsid Convention

The legal norms that govern the applicable law to disputes submitted to the International Centre for the Settlement of Investment Disputes (ICSID) can be considered a system in progress. Although the rule contained in Article 42(1) of the Convention on the Settlement of Investment Disputes between States and Nationals of Other States, signed in Washington in 1969, seems simple, case law and scholarship on the subject has been through recent transformation, including the role of international law and the power of the Tribunal to determine the applicable law. This article will address the most relevant aspects on the issues pertaining to conflict of laws in the ICSID environment, including the role of party autonomy and its limitations, and the interaction between municipal and international law in the determination of the law applicable to an Investor-State arbitration under the auspices of ICSID. Investor-State arbitration; private international law; party autonomy.