Arizona v. United States

Holding: The lower courts erred in holding that Section 2(B) of Senate Bill 1070 - which requires police to check the immigration status of persons whom they detain before releasing them and which allows police to stop and detain anyone suspected of being an undocumented immigrant " should not go into effect while its lawfulness is being litigated because it is not sufficiently clear that the provision is preempted. Section 3 " which makes it a state crime for someone to be in the United States without proper authorization " is preempted because Congress left no room for states to regulate in that field, or even to enhance federal prohibitions. Section 5(C) -which makes it a state crime for undocumented immigrants to apply for a job or work in Arizona " is preempted as imposing an obstacle to the federal regulatory system. Section 6 " which authorizes state law enforcement officials to arrest without a warrant any individual otherwise lawfully in the country, if they have probable cause to believe that the individual has committed a deportable offense " is preempted because whether and when to arrest someone for being unlawfully in the country is a question solely for the federal government.

Plain English Summary: Arizona had taken the lead, in 2010, in a renewed effort by states to adopt policies that would control many of the aspects of the daily lives of hundreds of thousands of immigrants who had entered the U.S. without legal permission to do so. The law has been challenged by various civil rights groups as a form of racial bias, but that was not an issue before the Supreme Court. The law also had been challenged by the federal government as unconstitutional, on the theory that Arizona was trying to move in on the federal government"s superior power to enforce federal immigration laws. That is the challenge that the Court decided Thursday. In the end, by a vote of 5-3, the Court nullified three of the four provisions because they either operated in areas solely controlled by federal policy, or they interfered with federal enforcement efforts. Nullified were sections making it a crime to be in Arizona without legal papers, making it a crime to apply for or get a job in the state, or allowing police to arrest individuals who had committed crimes that could lead to their deportation. The Court left intact " but subject to later challenges in lower courts " a provision requiring police to arrest and hold anyone they believe has committed a crime and whom they think is in the country illegally, and holding them until their immigration status could be checked with federal officials.

Judgment: Affirmed in part, reversed in part, and remanded., 5-3, in an opinion by Justice Kennedy on June 25, 2012. Justices Scalia, Thomas and Alito each filed opinions concurring in part and dissenting in part. (Kagan, J., recused)