As a scholar, Slaughter has had a focus on integrating the study of international relations and international law, using international relations theory in international legal theory. In addition, she has written extensively on European Union politics, network theories of world politics, transjudicial communication, liberal theories of international law and international relations, American foreign policy, international law, and various types of policy analysis. She has written books: "International Law and International Relations" (2000), "A New World Order" (2004), "The Idea that is America: Keeping Faith with our Values in a Dangerous World" (2007), and "The Crisis of American Foreign Policy: Wilsonianism in the Twenty-first Century" (with G. John Ikenberry, Thomas J. Knock, and Tony Smith) (2008), as well as three edited volumes on international relations and international law, and over one hundred extended articles in scholarly and policy journals or books.