Legitimacy and Effectiveness of the Investor–State Dispute Settlement Mechanism: Directions for Modernisation

The article examines the legitimacy and effectiveness of the investor–State dispute settlement mechanism as embedded in international investment agreements and bilateral investment treaties. It identifies the principal drivers of reform, focusing on the need to recalibrate the balance between public interests and investor protection, enhance the predictability of treaty standards, and clarify the permissible scope of State regulatory action. The study systematises leading reform trajectories, including procedural adjustments to arbitration, strengthened transparency and independence requirements, the introduction of procedural filters to deter abuse and manifestly unmeritorious claims, and the integration of consensual dispute resolution as a preventive tool. Particular attention is paid to institutional redesign options, such as appellate review and the potential replacement of fragmented ad hoc procedures with a standing mechanism, assessed through their implications for legal certainty and confidence in the investment protection regime.