Assumptions about territory permeate legal systems. American law is no exception. Territoriality is a defining attribute of the Westphalian state, the model upon which the framers of the US Constitution based their aspirations for a new nation. Under Westphalian principles the scope of a sovereign's law corresponds to the geographic boundaries of the sovereign's territory, what Miles Kahler, in his introduction to this volume, calls “jurisdictional congruence.”

Yet it is increasingly common to assert that Westphalian territorial sovereignty is breaking down – that we are entering a borderless world in which international forces permeate the once-hard shell of the state. Globalization, many argue, is rapidly eroding the significance of territorial boundaries (for example, Ohmae 1990; Held et al. 1999). Capital, labor, goods, and ideas are said to move largely without regard for political borders, radically transforming our polities and economies. These claims are controversial and have spawned fierce debate in economics and political science. Within legal scholarship, by contrast, the domestic impacts of globalization have received less sustained attention. Yet legal rules and practices provide an important and overlooked window on the alleged impacts of globalization, particularly with regard to territoriality.

All legal systems presuppose some relationship between law and territory. I call these rules of legal spatiality. This chapter charts the evolution of legal spatiality in the United States, and offers several causal arguments about this evolution and its connections to shifts in international security and economics.