A federal judge earlier blocked the key parts of the law, agreeing with the Obama administration that the state law was trumped by federal law. But four other states have passed similar laws, and their fate will depend on an eventual Supreme Court ruling in the Arizona case.
The case is liable to have implications in the presidential election as candidates vie for the growing Hispanic vote. Two out of three Hispanic voters cast their ballots for Barack Obama in 2008.
"The four provisions of [the state law] enjoined by the courts below authorize and direct state law enforcement officers to cooperate and communicate with federal officials regarding the enforcement of federal immigration law and impose penalties under state law for non-compliance with federal immigration requirements," Arizona told the high court in a brief.
The injunction bars enforcement of provisions of the law requiring police officers to question people about their immigration status during routine law enforcement operations, if officers have reason to suspect people are not in the United States legally.
The injunction also blocks a provision that criminalizes failure to apply for or carry alien registration papers, and a third that makes it illegal "for an unauthorized alien to solicit, apply for or perform work." Another blocked provision allowed police to arrest aliens thought to have committed a deportable offense.
Justice Antonin Scalia was the only justice in argument Wednesday who insisted the Constitution gives the states the right to enforce their own illegal alien polices, SCOTUSBLOG.com reported.
But most of the justices appeared ready to accept that Arizona police would act responsibly when they detain individuals they think are in the United States illegally, the report said.
Based on the justices speaking from the bench, SCOTUSBLOG said, not all of the provisions in the state law may survive.
On Tuesday, Sen. Charles Schumer, D-N.Y., said during a Senate Judiciary subcommittee hearing if the court upholds part or all of Arizona's immigration-enforcement law in its ruling, expected in late June, he would introduce a bill expressly to prevent states from enacting their own immigration-enforcement laws.
"I believe it is simply too damaging to our economy, and too dangerous to our democracy, to have 50 different states doing 50 different things with regard to immigration policy," Schumer said in opening remarks.