All international organizations exists in the conceptual and legal space between state sovereignty and legal obligation. They are created by the commitments made by sovereign states, and their purpose is to bind those states to their commitments. This chapter examines three forces in world politics: the commitments states make to international organizations, the choices states make regarding compliance and non-compliance with those commitments, and the powers of enforcement held by each international organization. Some international organizations are able to coerce their member states into complying with their commitments: for instance, the UN Security Council has a military component and the IMF has coercive leverage over its borrowers. But far more commonly they are left to find ways to cajole or induce compliance from their members. In each organization, the particular relationship between obligation, compliance, and enforcement is different, and these differences create interesting patterns of politics.

The main problems of international economics and international politics are at some level also problems of international organization. As interdependence increases, the importance of international organizations increases with it. We find international organizations in one form or another at the heart of all of the political and economic challenges of the twenty-first century. From international credit markets to endangered species to torture, today's leading controversies all involve some measure of international cooperation and commitment, managed through a formalized international organization (IO). Some IOs work well and some work hardly at all; some need reform, some need abolishing, and some need strengthening.