International courts have proliferated significantly in the international system, growing from only a handful of courts a century ago, to over 100 judicial or quasi-judicial bodies today. Prominent international courts include the International Court of Justice (ICJ), the International Criminal Court (ICC), the European Court of Justice (ECJ), and the World Trade Organization's (WTO) Dispute Settlement Understanding. International courts operate at the regional and global levels and cover a wide variety of issues such as territorial disputes, human rights, the law of the sea, trade, investments, and the use of military force.
While the number of international courts has increased significantly over time, there is considerable variation across courts. First, some international courts receive much stronger and broader state support than other courts. The Rome Statute, which recognizes the jurisdiction of the ICC, has currently been ratified by 111 countries, or over 55% of all states in the world. The World Trade Organization's adjudication mechanism receives a high level of international support as well, with 153 states (75%) belonging to the organization today. Other courts receive significantly less international support, such as the ICJ, where only one third of states in the world accept the compulsory jurisdiction of the Court (Alexandrov 1995).
Second, there is considerable variation in the design of international courts. Some courts, such as the ECJ, have a limited regional membership scope, while other courts, like the ICJ and the ICC, are more global and universal in their orientation.