Tonya L. Putnam is an Assistant Professor at the Department of Political Science at Columbia University] I’m very pleased to have been asked to contribute my thoughts on Karen Alter’s The New Terrain of International Law. Alter’s cogently argued new book exemplifies what well-executed interdisciplinary scholarship can achieve. It puts into productive dialogue several core preoccupations of political scientists, international lawyers, and practitioners as they relate to the growing universe of international courts (ICs). Not only does the resulting analysis map the outputs of, and relationships between intensively studied ICs like the ECJ, the ECtHR, and the WTO panel system, and more recently created, and less well-known, ICs and court-like bodies, it simultaneously theorizes the political interactions that create, sustain, confound, and (at times) transform their activities. From it we gain a compelling picture of how new-style ICs are using international law to reshape political interactions spanning the interstate to the local level around issues from property rights to human rights. The contributions of The New Terrain of International Law are too many to enumerate in detail. In the space I have here, therefore, I focus on two areas where future scholars can benefit from the foundation Alter lays in this volume. I then propose a set of questions about whether further proliferation of ICs may begin to complicate international affairs.