This chapter considers the relevance of international law within the U.S. legal system to the United States’ initiation and conduct of war, and it also discusses a variety of international law-related issues that have arisen in connection with the “war on terrorism” following the attacks of September 11, 2001. After briefly reviewing some of the most relevant treaties relating to war and warfare, the chapter considers the Constitution’s distribution of war authority between Congress and the president, as well as the contours of the 1973 War Powers Resolution. It then discusses how international law, including the provisions in the UN Charter relating to the authority of the Security Council, as well as collective self-defense treaties, might affect the president’s war authority. The chapter also discusses legal issues relating to the placement of U.S. troops under foreign or UN command. The chapter then shifts to the “war on terrorism,” and discusses the relevance of international law, including the Geneva Conventions, to issues concerning the scope of the military’s detention authority in that conflict. International law and other issues relating to the use of military commissions to try terrorist suspects are also considered. The chapter concludes by discussing legal debates relating to coercive interrogation and targeted killing.
