To prevail this year, the administration must convince at least one of the five to switch sides and rule the state is going too far and interfering with the federal government's control over immigration policy.
The election-year legal battle goes to the heart of the dispute between Republicans and Democrats over what to do about the estimated 11 million illegal immigrants in the country.
Arizona and five other Republican-led states seek a stepped-up effort to arrest and deport illegal immigrants. They say the federal system is broken and fault Obama for a "relaxed" enforcement policy.
If cleared by the courts, Arizona would tell its police to check the immigration status of people they lawfully stop and suspect of being in the country illegally. If they were unable to show a driver's license or other "proof of legal presence," they would be arrested and held for federal immigration agents. Arizona also would make it a crime for illegal immigrants to seek work or to fail to carry immigration documents.
The Obama administration favors targeted enforcement, not mass arrests of illegal immigrants. The administration has gone after drug traffickers, smugglers, violent felons, security risks, and repeat border crossers. Last year, nearly 400,000 people were deported, a record high. At the same time, the administration says mere "unlawful presence" in this country is not a federal crime, and it opposes state efforts to round up and arrest more illegal immigrants.
Alabama, Georgia, South Carolina, Indiana, and Utah also have adopted tough immigration enforcement laws. But judges have blocked many of their provisions, awaiting a ruling from the Supreme Court..
Washington lawyer Paul Clement, President George W. Bush's solicitor general, will argue for Arizona and Republican Gov. Jan Brewer on Wednesday; Obama's solicitor general, Donald B. Verrilli Jr., will argue the Democratic administration's case.
Clement is arguing for a stronger state role in enforcing the immigration laws, a traditional federal function. Verrilli is contending that Arizona's "maximum enforcement" policy for immigration goes too far and conflicts with federal policy.
The court's decision, expected by the end of June, could ignite the immigration issue in the presidential campaign.
Republican presidential candidate Mitt Romney has said he supports laws in Arizona and elsewhere that seek to drive away illegal immigrants. "The answer is self-deportation," he said in one debate.
Obama, on the other hand, has expressed concern about the effect on millions of normally law-abiding Latinos, including those with U.S. citizenship.
The Arizona law "potentially would allow someone to be stopped and picked up and asked where their citizenship papers are based on an assumption," Obama said in a recent interview. He also supports the DREAM Act, a proposal that would offer a path to citizenship for young illegal immigrants who earn diplomas or serve in the military.