The Supreme Court unanimously rejects a White House power grab.
Justice Anthony Kennedy, joined by Chief Justice John Roberts and the Court's liberals, ruled that the state flew too close to the federal sun. On the overturned provisions—like making it a misdemeanor to apply for a job without citizenship or a visa—the majority held that Congress had deliberately "occupied the field" under pre-emption doctrine, and Arizona had thus intruded on federal prerogatives.
However, the Justices said that Arizona police will be allowed to verify the legal status of people who come in contact with law enforcement. That's because Congress has always envisioned joint federal-state immigration enforcement and explicitly encourages state officers to share information and cooperate with federal colleagues.
Two of the three dissenting Justices—Samuel Alito and Clarence Thomas—agreed with this Constitutional logic but disagreed about which Arizona rules conflicted with the federal statute. The only major dissent came from Justice Antonin Scalia, who offered an even more robust if idiosyncratic defense of state prerogatives going back to the Alien and Sedition Acts. (Justice Elena Kagan recused herself.)
The 8-0 rebuke to President Obama turns on what Justice Samuel Alito describes in his dissent as "an astounding assertion of federal executive power." The White House argued that Arizona's laws conflicted with its enforcement priorities, even if state laws complied with federal statutes to the letter. In effect, the White House claimed that it can nullify any otherwise legitimate state law that it disagrees with.
Some powers do belong exclusively to the federal government, and control of citizenship and the borders is among them. But if Congress wanted to prevent states from using their own resources to check immigration status, it could. It never did so. The Administration was in essence asserting that because it didn't want to carry out Congress's immigration wishes, no state should be allowed to do so either. Every Justice rightly rejected this remarkable claim.
One lesson of this case is that the Roberts Court does not practice the radical activism of liberal myth. Its very careful jurisprudence is aimed at protecting the U.S. federalist system, in which states and the federal government share sovereignty and both possess rights that the other is bound to honor.
We happen to share the Obama Administration's desire for a welcoming, nonpunitive immigration policy, but it can't accomplish that by asserting power it doesn't have. Full marks to the Court for striking the proper Constitutional balance.