CNN reports the health care ruling will happen Thursday.
WASHINGTON (CNN) -- The U.S. Supreme Court ruled largely in favor of the federal government Monday in a case involving Arizona's immigration law, but it upheld the most controversial provision involving police checks on people's immigration status while enforcing other laws.
In a decision sure to ripple across the political landscape in a presidential election year, the court's 5-3 ruling struck down key parts of the Arizona law.
"The national government has significant power to regulate immigration," Justice Anthony Kennedy wrote in the majority opinion, adding that "Arizona may have understandable frustrations with the problems caused by illegal immigration while that process continues, but the state may not pursue policies that undermined federal law."
The majority concluded the federal government had the power to block SB1070, though the court upheld one of the most controversial parts of the bill -- a provision that lets police check a person's immigration status while enforcing other laws if "reasonable suspicion" exists that the person is in the United States illegally.
In its ruling, the high court made clear the immigration status provision could still face future constitutional challenges depending on how the state enforces it.
The federal government challenged four provisions of the Arizona law that never were enforced, pending the legal ruling.
Provisions struck down included:
-- Authorizing police to arrest immigrants without warrant where "probable cause" exists that they committed any public offense making them removable from the country.
-- Making it a state crime for "unauthorized immigrants" to fail to carry registration papers and other government identification.
-- Forbidding those not authorized for employment in the United States to apply, solicit or perform work. That would include immigrants standing in a parking lot who "gesture or nod" their willingness to be employed.
Justice Antonin Scalia, writing for the minority, argued the court's ruling encroached on Arizona's sovereign powers.
"If securing its territory in this fashion is not within the power of Arizona, we should cease referring to it as a sovereign state," Scalia wrote in the dissent backed by Justices Samuel Alito and Clarence Thomas.
The majority included Kennedy, Chief Justice John Roberts, Justice Steven Breyer, Justice Ruth Bader Ginsburg and Justice Sonia Sotomayor.
Justice Elena Kagan did not hear the case. Before taking the bench last year, she had been involved in the administration's initial legal opposition to the law as solicitor general.
The Obama administration had argued immigration matters were strictly a federal function.
The ruling is likely to have widespread implications for other states that have or are considering similar laws.
Fed up with illegal immigrants crossing from Mexico -- and what they say is the federal government's inability to stop it -- legislators in Arizona passed a tough immigration law. The federal government sued, saying that Arizona overreached.
At issue was whether states have any authority to step in to regulate immigration matters or whether that is the exclusive role of the federal government. In dry legal terms, this constitutional issue is known as pre-emption.
During an April hearing, Paul Clement, lawyer for Arizona, told the high court the federal government has long failed to control the problem, and that states have discretion to assist in enforcing immigration laws.
But the Obama administration's solicitor general, Donald Verrilli, strongly countered that assertion, saying immigration matters are under the federal government's exclusive authority and state "interference" would only make matters worse.
"If, in fact, somebody who does not belong in this country is in Arizona, Arizona has no power?" Scalia asked. "What does sovereignty mean if it does not include the ability to defend your borders?"
Even the more liberal Sotomayor told the federal governments' lawyer that key parts of his arguments were "not selling very well."
Several other states followed Arizona's lead by passing laws meant to deter illegal immigrants. Similar laws are under challenge in lower courts in Georgia, Alabama, Utah, Indiana and South Carolina. Arizona's appeal is the first to reach the Supreme Court.
Arizona is the nation's most heavily traveled corridor for illegal immigration and smuggling.
Federal courts had blocked four elements of the state's Support Our Law Enforcement and Safe Neighborhoods Act, known as SB 1070.
During the 70-minute arguments in April, Clement faced relatively little tough questioning from left-leaning members of the bench.
"There will be a significant number of people who will be detained at the stop, or in prison, for a significantly longer period of time" if the state law is allowed to be enforced,