In a much-anticipated ruling, the U.S. Supreme Court has reiterated that the federal government controls national immigration policy — that the national government is the “single sovereign” in charge of “a comprehensive and unified system to keep track of aliens within the nation’s borders.” Arizona v. United States, No. 11–182 (June 25, 2012).

Of particular importance to employers, the Court struck down a provision of an Arizona law that made it a crime for a non-citizen illegally in the state to either apply for work, accept employment or perform work as an employee or independent contractor. The decision will likely preclude most state efforts to prevent illegal immigrants from obtaining employment inside state borders. Employers remain subject to federal prohibitions on the employment of undocumented workers, of course.


In an effort to avoid the effects of illegal immigration, the state of Arizona in 2010 enacted what has become known as S.B. 1070. The law included several criminal provisions intended to encourage illegal aliens to leave Arizona. It made it a crime to be in Arizona without legal immigration papers (Section 3); directed state police to arrest — without a warrant — anyone believed to have committed any crime that would lead to deportation (Section 6); and required officers who arrest an individual for a suspected violation of law and who have reason to believe the individual is an undocumented immigrant to detain that individual until they can check with the federal government concerning the legality of that individual’s presence in the United States (Section 2(B)). The law also made it a state misdemeanor for “an unauthorized alien to knowingly apply for work, solicit work in a public place or perform work as an employee or independent contractor” in Arizona. Section 5(C).

The federal government challenged S.B. 1070 as “preempted” by federal power over immigration matters and specific immigration laws passed by Congress. Lower federal courts ruled that the four provisions of the law described above impermissibly conflict with the national power over immigration and congressional immigration laws and are thus invalid. The dispute went to the high court.

Supreme Court’s Decision

The Supreme Court ruled that the provisions criminalizing undocumented presence in Arizona (Section 3), the warrantless arrest provision (Section 6) and the provision criminalizing efforts to obtain employment (Section 5(C)) conflict with the national immigration power and laws and are, therefore, invalid. It said that there is not enough information at this point to determine whether Section 2(B)’s verification requirement is entirely unlawful, but ruled that individuals could challenge particular applications of that provision.

The Justices concluded that the national government has the broad and exclusive power to determine matters of immigration and alien status in the United States.

IRCA Provides a Comprehensive Framework

Turning to Arizona’s effort to criminalize attempts by illegal immigrants to apply for or work in Arizona, the Court said that such a criminal penalty conflicts with the federal regulatory scheme related to employment of illegal immigrants. It stated that the Immigration Reform and Control Act of 1986 (IRCA) provides a comprehensive framework for “combating the employment of illegal aliens.”

The IRCA makes it illegal for employers to knowingly hire, recruit, refer or continue to employ unauthorized workers, and requires employers to verify prospective employees’ employment authorization status on the I-9 form. But although the IRCA imposes both civil and criminal penalties on employers who violate its requirements, it imposes only civil penalties on illegal immigrants who seek or engage in unauthorized employment.

The Court concluded that the text, structure and history of IRCA show that “Congress made a deliberate choice not to impose criminal penalties on aliens who seek, or engage in, unauthorized employment.” Arizona’s contrary decision to impose criminal penalties on aliens who seek or engage in unauthorized employment contradicts and conflicts with that congressional decision and is an obstacle to the regulatory system Congress chose, the Court ruled, and it is therefore invalid. The Justices reached this decision even though they recognized that Section 5(C) “attempts to achieve one of the same goals as federal law — the deterrence of unlawful employment” and involves only a “conflict in the method of enforcement.”

What Does This Mean for Employers?

The Court’s focus on Congress’ comprehensive regulatory scheme regarding employment of illegal immigrants, and its conclusion that a conflict in the method of enforcement “can be fully as disruptive to the system Congress enacted as conflict in overt policy,” means it will likely be difficult for states to justify attempts to regulate employment of illegal immigrants. Several states, including Alabama, have enacted prohibitions on employment of or by illegal immigrants that go beyond or differ from the prohibitions included in federal law. We can expect such state laws to face continuing challenges and to be invalidated by lower courts on grounds similar to those that invalidated the Arizona law.

Naturally, employers must remain vigilant in their compliance with federal prohibitions on the employment of undocumented workers.