Negative externalities pervade immigration law. For example, immigration rules can cause negative economic externalities by barring foreign nationals whose participation would make labor markets more efficient. On the other hand, sweeping executive-branch measures to assist immigrants may unduly expand executive power and yield adverse effects on governance. This essay divides immigration's negative externalities into three categories: economic, relational, and rhetorical. It then argues for specific legal and policy measures, including tailored executive discretion over deportation; more robust court review of immigration (...) restrictions that affect foreign nationals outside the United States; and classifying deportation of lawful permanent residents of the United States as punishment requiring advance notice that specific acts can prompt removal, like the notice the Constitution's Ex Post Facto Clause requires for criminal laws. (shrink)