U.S. immigration law is premised on the fundamental idea that it is permissible, desirable, and necessary to restrict immigration into the United States and to treat borders as a barrier to entry rather than a port of entry. In this Article, Kevin Johnson seeks to add to the scholarly dialogue on immigration law by considering the possible reimagination of the meaning and significance of the international border. Specifically, Professor Johnson attempts to articulate arguments for eliminating the border as a legal construct that impedes the movement of people into the United States. In making a case for the consideration of more open borders, this Article calls for the study of a potentially radical change in immigration law. The argument obviously runs counter to the historical restriction of immigration, as well as the wave of border fortification that marked the 1990s and increased dramatically in the wake of the tragic events of September 11, 2001. To this point, politicians, activists, and scholars have not seriously considered opening the borders to all comers; few theorists question the underlying premise that a nation-state has the sovereign power to enact immigration restrictions or that it might exercise that power to admit all persons who seek entry into the country. Similarly, legal scholarship generally treats closed borders as the assumed state of immigration law, with the law facilitating the efficient, fair, and rational administration of a comprehensive system of immigration controls; put differently, legal scholarship ordinarily offers ideas on improving this system, rather than on questioning its foundational premises. Part I of this Article contrasts the views of political theorists on open borders. Part II studies the moral, economic, and policy arguments for open borders, revealing the difficulty in squaring immigration restrictions with the commitment of liberal theory to individual rights. This section further suggests the possible move toward more open borders, with regional integration and more open labor migration akin to that which has evolved in the European Union possibly serving as a step toward broader change.