Intervening in International Justice
Third States before Courts and Tribunals
Cambridge Studies in International and Comparative Law Series

The intervention of States in legal proceedings touches upon some of the most beguiling questions in international dispute settlement. These include questions of treaty interpretation, obligations erga omnes, the sources of judicial power and rulemaking, the nature of incidental proceedings, the Monetary Gold doctrine of indispensable parties, cross-fertilization between judicial and arbitral bodies, and principles of jurisdiction, party autonomy, and res judicata. As jurists and scholars tend to address these questions in isolation, however, each development in third-State practice has raised unimagined issues of first impression-such as the 2022 declarations of dozens of States exploring mass intervention before the International Court of Justice in Ukraine v. Russia, and the participation of neighbouring States without China's presence in the 2016 South China Sea arbitration. By applying conceptual, comparative, and historical approaches to international justice, this book instead offers a uniquely holistic assessment of the practice and prospective development of intervention.

1. Introduction; 2. The treaty framework of intervention before the international court of justice; 3. The regulation of intervention by the international court of justice; 4. The protection and limits of party autonomy in inter-state disputes; 5. The legal interests of third states; 6. The third-party effects of judicial decisions; 7. The multiplication of intervention mechanisms; 8. The prospect of intervention in inter-state arbitration; 9. Conclusion.

Brian McGarry became Assistant Professor of Public International Law at Leiden University after being appointed to teach dispute settlement at the Graduate Institute and Sciences Po Paris. He practices before the ICJ and ITLOS, and clerked for the PCA. His Ph.D. received the University of Geneva's award for best thesis in law or political economy.