What's at Stake in Tomorrow's Supreme Court Immigration Showdown?

As J.D. Tuccille and Jacob Sullum each noted yesterday, the Supreme Court will hear oral arguments tomorrow in Arizona v. United States. At issue are four provisions from the state's controversial immigration control law S.B. 1070, including Section 2(B), which requires state law enforcement officials to make a "reasonable attempt" to determine the immigration status of any person they encounter during "any lawful stop, detention, or arrest" if those officials have a "reasonable suspicion" that the person may be in the country illegally.

Although most of the attention directed at S.B. 1070 has focused on the likelihood that it will encourage racial profiling and other police abuses, tomorrow's case centers on a different question. The legal issue before the Supreme Court is something known as preemption, which means that if a state law is found to conflict with a legitimate federal law, the state law must fall.

According to the Obama administration, which will be represented in Court tomorrow by Solicitor General Donald Verrilli, "S.B. 1070 would supplant federal policy with a new and contrary state policy." Arizona, which will be represented by former solicitor general Paul Clement, argues that that there is no conflict between the state and federal approaches in this case, and in fact, "S.B. 1070 does not impose its own substantive immigration standards, but simply uses state resources to enforce federal rules."

Over the past few years, the Supreme Court has handed down several major preemption rulings. Unfortunately for the Obama administration, none of them bode very well for the federal government in this case.

The most significant is last year's Chamber of Commerce v. Whiting (2011), where the Court voted 5-4 to uphold the Legal Arizona Workers Act, which requires all Arizona employers to verify their workers' immigration status via E-Verify, and imposes draconian penalties, including the loss of business licenses, on firms that hire unauthorized immigrants. The Court, divided along conservative-liberal lines, ruled that the Arizona regulation was not preempted by federal law.

The Court's 2009 ruling in Wyeth v. Levine may also prove relevant. In that case, the Court ruled by a 6-3 majority that federal law did not preempt a state failure-to-warn lawsuit against a pharmaceutical company even though the drug warning label in question had been approved by the Federal Drug Administration. As Justice John Paul Stevens wrote for the majority, "in all preemption cases, and particularly in those in which Congress has legislated in a field which the states have traditionally occupied, we start with the assumption that the historic police powers of the states were not to be superseded by the federal act unless that was clear by the manifest purpose of Congress."

Justice Anthony Kennedy sided with the liberal majority in that ruling, as did Justice Clarence Thomas, who earned some rare praise from progressives in the process. Two years later the Court unanimously rejected a similar federal preemption argument in Williamson v. Mazda Motor of America (2011), ruling that the federal Motor Vehicle Safety Act did not trump a more restrictive California requirement that rear car seats have both lap and shoulder seat belts (federal law required only lap belts in rear seats).

Those cases all dealt with economic regulations, of course, not immigration controls. But if Arizona succeeds in framing its case as one where the state is simply exercising its historic police powers to protect the health, welfare, and safety of citizens by enforcing federal law (not supplanting or undermining federal sovereignty), the distinction won't matter and the provisions from S.B. 1070 will likely survive.