By Margaret Hu, a visiting assistant professor at Duke Law School. She is the author of a forthcoming article in the U.C. Davis Law Review titled "Reverse-Commandeering."
As the Supreme Court heard oral argument in Arizona v. U.S., one of the main legal questions it considered is this: Whether Arizona’s Senate Bill 1070 (SB 1070) is preempted by federal immigration law under the Supremacy Clause. This is a statutory-driven inquiry that misses the constitutional mark. The more relevant question is this: Whether SB 1070 poses a threat to the vertical separation of powers.
Increasingly, immigration federalism laws like SB 1070 — state and local attempts to control unwanted migration — exemplify the inverse of the problem posed by the impermissible commandeering of states under the Tenth Amendment. Specifically, the recent tidal wave of thousands of immigration control efforts proposed by state and local governments can best be characterized as “reverse-commandeering” laws. Setting migration policy at the national level, like establishing a national currency, falls within the sole power of the federal government. Reverse-commandeering by the states is an effort to usurp the federal government’s sole prerogative. This growing movement represents an attempt to control the terms of what federal resources and officers must be appropriated to accommodate a myriad of state immigration enforcement programs. It is a deliberate attempt to skew the immigration enforcement power in favor of the states.
In the years since Congress’s failure to pass comprehensive immigration reform legislation in 2006-07, state and local governments have considered over 7,000 immigration-related proposals. In the first quarter of 2011, 1,538 immigration bills and resolutions were considered in all 50 states and in Puerto Rico. By December 2011, 42 states and Puerto Rico had enacted 197 new laws and 109 new resolutions. A tiny handful of the most controversial state laws, such as the Legal Arizona Workers Act (LAWA) — the subject of the Court's recent decision in Chamber of Commerce v. Whiting — and SB 1070 — the subject of the Court's current consideration in Arizona v. U.S. — have received challenges in federal court. Consequently, such challenges address only the tip of an immigration federalism iceberg.

Washington or pesky federal judges. But as I'll explain, these attorneys general -- call them the Cuccinelli 13 -- don't really believe their own argument. They just want their states to be able to keep discriminating against gays and lesbians.