The course provides an introduction to public international law. We begin with an introduction to the international legal system, which differs from our national legal system in intriguing ways. As we learn the primary rules and institutions that govern this unique legal system, we ask the fundamental questions: Where does international law come from? Whom does it govern? How is it enforced? How is it different from domestic law? Once we master the basics, we turn, in Unit II, to the question of how this international system interacts with our more familiar national legal system. While our main focus will be on foreign affairs law of the United States, we will also look at other countries’ foreign affairs law. In Unit III, we turn to specific substantive areas of international law, focusing on current topics, such as the international response to the crisis in Syria (humanitarian law and international criminal law).