The article examines the determination of the applicable law in ICSID investment arbitration in light of Article 42 of the 1965 Washington Convention and assesses how deficiencies in identifying the governing legal framework may be framed as an excess of powers and, accordingly, generate annulment risk under Article 52 of the Convention. It highlights the role of party autonomy and the limits of the parties’ agreement on applicable law for legal certainty, procedural predictability, and the reviewability of the tribunal’s reasoning. Particular attention is paid to distinguishing an error in the application of law from a situation where the tribunal effectively fails to apply the law that should govern the merits. The study also addresses the importance of a coherent legal qualification approach when combining domestic and international legal norms within a single dispute. It concludes that a consistent and explicit justification of the applicable law functions as a procedural safeguard and a key condition for the stability of ICSID awards.
Dmitry Semenovich Belkin (2020) studied this question.