This chapter explores the interplay between international law, territorial sovereignty, and extraterritorial regulation – the use of national law to address global or transboundary challenges. It describes how particular legal theories about global governance provided cover for an expansive view of national power that sought to remake international jurisdictional law. The chapter traces the rise, beginning in the late 1980s and early 1990s, of extraterritorial regulation in the United States, and then, the retreat from broadest forms of extraterritorial judicial jurisdiction. The chapter deals with two normative reflections about the interplay between extraterritoriality and international law. First, contrary to what is frequently assumed, the use of domestic courts and national law applied abroad is rarely a complementary way to develop international norms, but a way to undermine them. Second, the rhetoric of transnationalism has played into the hands of isolationists and anti-internationalists, who have sought to undermine international institutions and the multilateral cooperation upon which international law rests.