The Unconstitutionality of State Regulation of Immigration through Criminal Law

The “mirror image” theory of cooperative state enforcement of federal immigration law is a phenomenon, one of the most wildly successful legal movements and ideas in decades. The mirror-image theory proposes that states can enact and enforce criminal immigration laws based on federal statutes. The theory that it is unobjectionable for a state to carry out federal policy is the basis of Arizona’s SB1070, similar immigration laws already in force in seven states, and copycat bills pending in dozens more. The mirror-image theory has succeeded not only in legislatures, but also as an idea in the larger political culture: it has been embraced by dozens of U.S. Senators and Representatives, by policy groups, private citizens, and commentators including George Will, Sarah Palin, and the editors of the New York Post and Washington Times. The mirror image theory is indeed appealing. But it is also fundamentally flawed. This article, the first to subject the mirror image theory to sustained scholarly scrutiny, demonstrates that the mirror image theory fails to identify a legitimate source of state power to legislate on immigration matters. No one denies that Congress and the Federal executive have exclusive authority over the substance and procedure of admission, exclusion and removal of non-citizens, documented and undocumented. To the extent there has ever been any question, this proposition was firmly established by a pair of Supreme Court decisions from 1876. The mirror image theory does not challenge this deep-rooted idea head-on, but instead proposes that state legislative authority over immigration flows from cases and provisions of the Immigration and Nationality Act (INA) authorizing states to assist in the enforcement of federal immigration law. However, those authorities contemplated state assistance with enforcement only through arrests. Arrest authority does not imply the power to legislate or prosecute. To the contrary, other provisions of the INA make clear that federal agencies have exclusive power to make prosecutorial and administrative decisions after arrest, and to create supplementary regulations. The mirror image theory rests on the erroneous premise that Congress has implicitly authorized state enforcement of federal immigration law. This article argues that state enforcement would be unconstitutional even if it were explicitly authorized by Congress. First, the federal immigration power is exclusive and non-delegable. Second, criminal prosecution and immigration enforcement is an executive power which Congress cannot remove from the President and share with non-Executive branch officials. Finally, the Supreme Court has held that states cannot prosecute crimes which affect only the sovereign interests of the United States. Accordingly, state immigration prosecutions are irremediably unconstitutional.