Immigration Separation of Powers and the President's Power to Preempt

This article explores the unique separation-of-powers issues raised in the immigration context, focusing on the respective powers of Congress and the President to preempt State law. Pursuant to traditional understanding, Congress and only Congress is constitutionally vested with the authority to displace conflicting State laws. Outside of the immigration context, the Supreme Court nonetheless has invoked competing theories of executive power to justify extending preemptive effect to executive decisions, while at the same time imposing significant doctrinal restrictions on its exercise. In its recent decision in Arizona v. United States, however, the Court departed from these existing doctrinal restrictions to hold that a conflict with the potential exercise of executive prosecutorial discretion suffices to displace State law. In doing so, it signaled an unprecedented expansion of the executive’s power to preempt, one without apparent limit. This article argues that considerations unique to immigration law undermine the utility of existing doctrinal frameworks for limiting executive preemption. Nonetheless, some restriction remains warranted. Given the limitations of the existing doctrines, it proposes a new approach to cabining executive authority in this context.