To address pressing issues related to the large number of aliens within its borders who do not have a lawful right to be in this country, the State of Arizona in 2010 enacted a statute called the Support Our Law Enforcement and Safe Neighborhoods Act. The law is often referred to as S. B. 1070, the version introduced in the state senate. See also H. 2162 (2010) (amending S. 1070). Its stated purpose is to “discourage and deter the unlawful entry and presence of aliens and economic activity by persons unlawfully present in the United States.” Note following Ariz. Rev. Stat. Ann. §11–1051 (West 2012). The law’s provisions establish an official state policy of “attrition through enforcement.” Ibid. The question before the Court is whether federal law preempts and renders invalid four separate provisions of the state law.
…The Government of the United States has broad, undoubted power over the subject of immigration and the status of aliens. See Toll v. Moreno, 458 U. S. 1, 10 (1982); see generally S. Legomsky & C. Rodríguez, Immigration and Refugee Law and Policy 115–132 (5th ed. 2009). This authority rests, in part, on the National Government’s constitutional power to “establish an uniform Rule of Naturalization,” U. S. Const., Art. I, §8, cl. 4, and its inherent power as sovereign to control and conduct relations with foreign nations, see Toll, supra, at 10 (citing United States v. Curtiss-Wright Export Corp., 299 U. S. 304, 318 (1936)). The federal power to determine immigration policy is well settled. Immigration policy can affect trade, investment, tourism, and diplomatic relations for the entire Nation, as well as the perceptions and expectations of aliens in this country who seek the full protection of its laws. See, e.g., Brief for Argentina et al. as Amici Curiae; see also Harisiades v. Shaughnessy, 342 U. S. 580, 588–589 (1952). Perceived mistreatment of aliens in the United States may lead to harmful reciprocal treatment of American citizens abroad. See Brief for Madeleine K. Albright et al. as Amici Curiae 24–30.
It is fundamental that foreign countries concerned about the status, safety, and security of their nationals in the United States must be able to confer and communicate on this subject with one national sovereign, not the 50 separate States.
…The pervasiveness of federal regulation does not diminish the importance of immigration policy to the States. Arizona bears many of the consequences of unlawful immigration. Hundreds of thousands of deportable aliens are apprehended in Arizona each year. Dept. of Homeland Security, Office of Immigration Statistics, 2010 Yearbook of Immigration Statistics 93 (2011) (Table 35). Unauthorized aliens who remain in the State comprise, by one estimate, almost six percent of the population. See Passel & Cohn, Pew Hispanic Center, U. S. Unauthorized Immigration Flows Are Down Sharply Since Mid-Decade 3 (2010). And in the State’s most populous county, these aliens are reported to be responsible for a disproportionate share of serious crime. See, e.g., Camarota & Vaughan, Center for Immigration Studies, Immigration and Crime: Assessing a Conflicted Situation 16 (2009) (Table 3) (estimating that unauthorized aliens comprise 8.9% of the population and are responsible for 21.8% of the felonies in Maricopa County, which includes Phoenix). Statistics alone do not capture the full extent of Arizona’s concerns. Accounts in the record suggest there is an “epidemic of crime, safety risks, serious property damage,
and environmental problems” associated with the influx of illegal migration across private land near the Mexican border. Brief for Petitioners 6. Phoenix is a major city of the United States, yet signs along an interstate highway 30 miles to the south warn the public to stay away. One reads, “DANGER—PUBLIC WARNING—TRAVEL NOT RECOMMENDED / Active Drug and Human Smuggling Area / Visitors May Encounter Armed Criminals and Smuggling Vehicles Traveling at High Rates of Speed.” App. 170; see also Brief for Petitioners 5–6. The problems posed to the State by illegal immigration must not be underestimated. These concerns are the background for the formal legal analysis that follows. The issue is whether, under pre-emption principles, federal law permits Arizona to implement the state-law provisions in dispute.
Federal law makes a single sovereign responsible for maintaining a comprehensive and unified system to keep track of aliens within the Nation’s borders. If §3 of the Arizona statute were valid, every State could give itself independent authority to prosecute federal registration violations, “diminish[ing] the [Federal Government]’s control over enforcement” and “detract[ing] from the ‘integrated scheme of regulation’ created by Congress.” Wisconsin Dept. of Industry v. Gould Inc., 475 U. S. 282, 288–289 (1986). Even if a State may make violation of federal law a crime in some instances, it cannot do so in a field (like the field of alien registration) that has been occupied by federal law. See California v. Zook, 336 U. S. 725, 730–731, 733 (1949); see also In re Loney, 134 U. S. 372, 375– 376 (1890) (States may not impose their own punishment
for perjury in federal courts).
Arizona contends that §3 can survive preemption be cause the provision has the same aim as federal law and adopts its substantive standards. This argument not only ignores the basic premise of field preemption—that States may not enter, in any respect, an area the Federal Government has reserved for itself—but also is unpersuasive on its own terms. Permitting the State to impose its own penalties for the federal offenses here would conflict with the careful framework Congress adopted. Cf. Buckman Co. v. Plaintiffs’ Legal Comm., 531 U. S. 341, 347–348 (2001) (States may not impose their own punishment for fraud on the Food and Drug Administration); Wisconsin Dept., supra, at 288 (States may not impose their own punishment for repeat violations of the National Labor Relations Act). Were §3 to come into force, the State would have the power to bring criminal charges against individuals for violating a federal law even in circumstances where federal officials in charge of the comprehensive scheme determine that prosecution would frustrate federal policies.
…These specific conflicts between state and federal law simply underscore the reason for field preemption. As it did in Hines, the Court now concludes that, with respect to the subject of alien registration, Congress intended to preclude States from “complement[ing] the federal law, or enforc[ing] additional or auxiliary regulations.” 312 U. S., at 66–67. Section 3 is preempted by federal law.”
– From the majority opinion in Arizona V. United States