State law must give way to federal law in at least two circumstances. First, the States are precluded from regulating conduct in a field that Congress, acting within its proper authority, has determined must be regulated by its exclusive governance. The intent to displace state law altogether can be inferred from a framework of regulation so pervasive that Congress left no room for the States to supplement it, or where there is a federal interest so dominant that the federal system will be assumed to preclude enforcement of state laws on the same subject. Second, state laws are preempted when they conflict with federal law. This includes cases where compliance with both federal and state regulations is a physical impossibility, and those instances where the challenged state law stands as an obstacle to the accomplishment and execution of the full purposes and objectives of Congress. In preemption analysis, courts should assume that the historic police powers of the States are not superseded unless that was the clear and manifest purpose of Congress.
The State of Arizona enacted the Support Our Law Enforcement and Safe Neighborhoods Act, S. B. 1070 (Ariz.), in 2010, and the United States sought an order which enjoined §§ 2(B), 3, 5(C), and 6 of S. B. 1070, codified, respectively, as Ariz. Rev. Stat. Ann. §§ 11-1051(B), 13-1509, 13-2928(C), and 13-3883(A)(5), claiming that all four sections were preempted by federal law. The Supreme Court found that §§ 3, 5(C), and 6 of S. B. 1070 were preempted by federal law; however, it was not clear at this stage of the case that § 2(B)--which required state officers to make a reasonable attempt to determine the immigration status of any person they stopped, detained, or arrested on some other legitimate basis--was preempted. Section 3 was preempted because it intruded on the field of alien registration, § 5(C) was preempted because it imposed criminal sanctions on aliens who sought or accepted employment when U.S. law did not make those activities a crime, and § 6 was preempted because it interfered with the system Congress had created for allowing the arrest of aliens who were in the United States unlawfully.
Are the four primary provisions of S.B. 1070 passed by Arizona preempted by federal immigration law?
The Supreme Court ruled in a 5-3 decision that the first, second and fourth provisions of S.B. 1070 were preempted by federal immigration law related to immigration concerns.