A controversial measure Arizona lawmakers passed to crack down on illegal immigration will now go before the Supreme Court, the justices announced Monday, but this is a different law from the one recently passed–and yet to go into effect–that has generated so much attention.

The Court’s decision to take the case places a harsh spotlight on Homeland Security Secretary Janet Napolitano for an apparent reversal on her views of how best to address immigration problems. It also puts added focus on Supreme Court nominee Elena Kagan and her role as Solicitor General in asking the high court to take the case.

The 2007 Arizona law now under review was an effort by state lawmakers to crack down on companies that hire illegal workers. The law sanctions employers who knowingly hire illegal employees. It also forces employers to participate in the national E-Verify database that tracks employment eligibility.

Critics contend the Legal Arizona Workers Act usurps the authority of the federal government which has traditionally enforced immigration laws.

“Business, labor, and civil rights organizations, which only rarely see eye to eye, joined in challenging the statute below; support the petition here; and individually and collectively recognize the fundamental need for review and clarification of the law by this Court,” U.S. Chamber of Commerce lawyer Carter Phillips wrote to the Supreme Court asking the justices to take the case and ultimately overturn the law.

Phillips said Arizona’s effort is part of a “crazy-quilt of state and local immigration statutes” that give rise to uncertainty for employers; many of whom have operations in multiple states.

Arizona argues that concern is unwarranted because its law works in concert with federal measures. “Although Congress prohibited the federal government from requiring employers throughout the country to use E-Verify, it did not prohibit state policymakers from requiring employers within their jurisdiction to use this federal program,” Arizona Solicitor General Mary O’Grady told the Court asking the justices to deny review.

The case comes from the Ninth Circuit U.S. Court of Appeals which upheld the law. A unanimous three-judge panel ruled “the Act does not attempt to define who is eligible or ineligible to work under our immigration laws. It is premised on enforcement of federal standards as embodied in federal immigration law.”

After many months of consideration, the Obama Administration drafted a brief to the Court asking the justices to resolve the apparent conflict between state and federal enforcement of immigration laws but ignore the dispute over the E-Verify requirement.

The government’s position puts Napolitano in the crosshairs of the controversy. The Obama Administration’s brief to the high court comes from the Solicitor General’s office but since Napolitano’s agency is largely responsible for immigration policy the brief effectively represents her view that federal law should trump the state statute.

If that is in fact Napolitano’s belief, it is a major reversal from three years ago when as Arizona’s governor she signed the bill into law. “[I]t is now abundantly clear that Congress finds itself incapable of coping with the comprehensive immigration reforms our country needs,” Napolitano said at the time explaining her reasons for endorsing the measure.

Monday’s announcement will also impact Kagan even though her name does not appear on the brief (Acting Solicitor General Neal Katyal is listed as counsel of record) it is very likely she played a central role in its formulation. Her contribution to the government’s brief is likely to come up during this week’s confirmation hearing. If confirmed, there is a good chance Kagan will not participate in the case because of her involvement as Solicitor General.

The outcome of the case could serve as a bellwether for another controversial immigration measure passed by Arizona lawmakers earlier this year. That law is not set to go into effect until next month but has already generated several lawsuits and the promise of a challenge from the Obama Administration. The law’s most vocal supporter, Arizona Governor Jan Brewer (R) says she’ll fight the matter to the Supreme Court, if necessary.