Chapter 1 begins with the role that political theory can play in public debate about immigration. Political theory can identify values and principles that can serve as guides to public judgment, clarify the sources of our disagreement, and perhaps even reduce the extent of disagreement about specific issues. The chapter then discusses four key dynamics in the politics of immigration: majoritarian politics, nationalism, capitalism, and liberal constitutionalism. It presents the idea of associative obligations and advances an intermediate position on immigration between closed borders and open borders rooted in an ethic of membership. It concludes with a roadmap of the book.