Argument: Protecting our borders is a purely federal function
"Arizona Immigration Law is Constitutionally Trembling." The Barr Code. May 3rd, 2010: "Protecting our borders is in fact a singularly federal function; reflecting the fundamental responsibility of the national government to protect our sovereignty. Traditionally, and appropriately, states have not been permitted to assume federal government functions; just as Washington should not be permitted to assert powers properly left to the states. This split of enforcement authority – while in modern times often not honored by the federal government – is codified in the Constitution, including in the Tenth Amendment."