In 1989, when the Cold War ended, there were six permanent international courts. Today there are more than two dozen that have collectively issued over thirty-seven thousand binding legal rulings. This book charts the developments and trends in the creation and role of international courts, and explains how the delegation of authority to international judicial institutions influences global and domestic politics. The book presents an in-depth look at the scope and powers of international courts operating around the world. Focusing on dispute resolution, enforcement, administrative review, and constitutional review, the book argues that international courts alter politics by providing legal, symbolic, and leverage resources that shift the political balance in favor of domestic and international actors who prefer policies more consistent with international law objectives. International courts name violations of the law and perhaps specify remedies. The book explains how this limited power—the power to speak the law—translates into political influence, and it considers eighteen case studies, showing how international courts change state behavior. The case studies, spanning issue areas and regions of the world, collectively elucidate the political factors that often intervene to limit whether or not international courts are invoked and whether international judges dare to demand significant changes in state practices.