International Law

This chapter examines the emergence of the Amicus Curiae phenomenon in international law, focusing on both public law institutions, such as the European Court of Human Rights (ECtHR), and international commercial arbitration bodies, including the World Trade Organization (WTO), the North American Free Trade Agreement (NAFTA), and the International Center for Settlement of Investment Disputes (ICSID). Initially resistant to third-party interventions, these institutions gradually opened up to amicus participation in the 1990s, driven by the recognition that their decisions often implicate broader societal interests beyond those of the formal parties. The chapter traces the increasing involvement of NGOs, interest groups, and other amici in international legal proceedings, as well as the development of procedural rules to govern their participation. It concludes that the amicus phenomenon in international law reflects a growing understanding of the public dimensions of transnational disputes and the need for more inclusive and transparent adjudicative processes.