On June 25, 2012, the United States Supreme Court ruled in a 5-3 decision to strike down three out of the four challenged provisions of Arizona’s immigration enforcement law, commonly known as S.B. 1070. The majority’s decision reaffirms the power of the federal government to set immigration policy and to preempt state laws that conflict with federal laws.

The Court blocked S.B. 1070 provisions that created new state misdemeanors for unauthorized aliens seeking or engaging in work in the state and for failure to complete or carry an alien registration document as required by federal statute. It also blocked the provision authorizing officers to arrest without a warrant a person whom an officer believes committed a public offense that makes the person removable from the United States.

The Court upheld the law’s best-known provision, which requires state law enforcement officers to make a reasonable attempt to determine the immigration status of individuals they stop or arrest if there is reason to believe the individuals might be unlawfully present in the United States. The Court found it was improper to enjoin this part of the law before state courts had an opportunity to interpret it and without some evidence that the measure as enforced conflicts with federal immigration law.

This week’s highly anticipated decision follows last year’s other notable Supreme Court immigration ruling in Chamber of Commerce of the United States of America et al. v. Whiting et al. In Whiting, the Court upheld the Arizona law that provides for revocation of business licenses for employers that employ unauthorized workers and requires Arizona employers to use E-verify, a federal, internet-based system used to confirm the immigration status of employees. Several states have similar laws requiring the use of E-verify by state employers and contractors. The Court’s recent decisions did not overturn or change these state E-verify requirements.  Multi-state employers must continue the difficult task of navigating the patchwork of state E-verify requirements.