Illegal Aliens will have a harder time after a 5-3 decision by the U.S. Supreme Court upholding the Legal Arizona Workers Act of 2007. It compels employers in Arizona to use the internet-based EVerify system to confirm that a new employee is lawfully in the U.S. The E-Verify system -- which was set up by the federal government for voluntary use -- is simple and easy-to-use. Arizona made this voluntary system mandatory: if a business fails to use E-Verify and knowingly hires illegal aliens, then Arizona can revoke its license to do business.

At issue was whether this Arizona law qualifies as a licensing-like statute that federal immigration law expressly allows States to enact. The Court majority upheld it as a licensing law not preempted by the federal law. Chamber of Commerce of the United States v. Whiting, 2011 U.S. LEXIS 4018 (May 26, 2011).

The Chamber of Commerce, perhaps at the insistence of liberals, challenged this mandatory Arizona approach as being somehow inconsistent with the voluntary federal scheme. Three Justices -- Ginsburg, Breyer, and Sotomayor, sided with the Chamber of Commerce and dissented from the Court's decision. Only Justice Sotomayor used the term "illegal alien"; the majority went with the term "unauthorized alien."

Justice Sotomayor explained that the Immigration Reform and Control Act of 1986 (IRCA) created a "comprehensive scheme prohibiting the employment of illegal aliens in the United States," but felt that this federal law preempted and prevented State laws from supplementing it.

Justice Breyer, who wrote a separate dissent, added his view that the Arizona law might impede another congressional goal: to "protect lawful workers from national-origin-based discrimination."

Obama-appointed Justice Kagan recused herself from participating in this decision, presumably because she was in the Department of Justice during part of the litigation. Her recusal weakened the liberal wing by one vote, but did not affect the outcome because there was a majority of five votes to uphold the Arizona law.

Interestingly, it was Justice Thomas who withheld his support from some sweeping language in the majority opinion about State power to regulate businesses in this way. In an unusual departure from the conservative bloc on the Court, and without explanation, Justice Thomas declined to join two portions of the opinion that commented on the congressional intent and goals.

Justice Thomas, who is known for downplaying the significance of "legislative intent," may have found it unnecessary and unwarranted for the Court to opine about what Congress supposedly intended with respect to this issue.

The bottom line is this: the Supreme Court has affirmed the power of States to take steps to end illegal immigration. Opponents of Arizona's SB 1070, the more recent law that authorizes police to question people on their immigration status if the police have a reason to believe the person is an illegal alien, may worry that the Supreme Court will uphold that law too. Other decisions that have stricken state or local efforts to stop illegal immigration, such as the law passed by the town of Hazleton in Pennsylvania, may now be revisited and also upheld.