The US Supreme Court will conclude its term on Wednesday with a hearing on Arizona's controversial law cracking down on illegal immigrants -- another case that could affect election-year politics.
After three days of hearings on President Barack Obama's landmark health reform law, the court will again examine the separation of federal and state powers when it looks at the legality of Arizona's identity checks.
The top US court announced in December that it would review the 2010 law in the southwestern state, which would allow police to stop suspected illegal immigrants and demand proof of citizenship without probable cause.
The law -- portions of which have been suspended after court challenges by the Obama administration -- is among several pieces of state legislation that the White House says infringe on the federal government's authority to regulate immigration.
"It is another example of the struggle between the federal government and the state governments over the Constitution's allocation of powers," said constitutional law expert Elizabeth Wydra, who filed an amicus brief backing the Obama administration.
The court is likely to deliver its rulings on both the immigration and the health care cases in June -- just a few months before voters go to the polls to decide whether Obama should be given a second term.
Steven Schwinn, a professor at the John Marshall Law School in Chicago, said the case "pits a politically conservative state against a Democratic administration over important federalism principles in the context of a critical public policy debate" before the November 6 election.
Last year, lower courts opted to strike sections of the law they said would place a burden on legal resident aliens in Arizona, where a third of the 6.6 million people is foreign-born and more than 400,000 are illegal immigrants.
But Arizona appealed, claiming that "the federal government has largely ignored Arizona's pleas for additional resources and help" in stemming the tide of illegal immigration into the state, which borders Mexico.
Arizona governor Jan Brewer -- who earlier this year was caught on camera pointing her finger in Obama's face in what looked to be a testy exchange on an airport tarmac -- has asked the high court to reinstate the suspended sections.
Beyond the identity checks without probable cause, the other sections in question would make it a crime to be in the United states unlawfully, and require non-citizens to carry their identity papers with them at all times.
Also at issue is a provision that would make it a crime for illegal migrants to seek work, and one authorizing law enforcement officials to stop anyone they believe may have committed a crime that would result in their expulsion.
Critics have charged that the law would encourage racial profiling, while supporters say tougher rules are needed to curb illegal immigration.
"It's a law that is very draconian. It would very much change our way of life," said Anthony Romero, the executive director of the American Civil Liberties Union (ACLU), who backs the Obama administration's position.
"This has an impact not only on undocumented immigrants but also on the American citizens who would be arrested based on the color of their skin," Romero told AFP.
In its motion filed with the Supreme Court, Arizona argues that SB 1070 is "perfectly congruent with federal law and federal objectives."
Schwinn noted that Arizona's "controversial approach has gained traction in some other states," with at least 36 states introducing legislation with elements similar to those in Arizona, five of which have been passed.
Eight of the court's nine justices will hear the case. Justice Elena Kagan, who once served as Obama's solicitor general, has recused herself. If there is a 4-4 tie, the lower court's decision to strike the provisions will be upheld.