Arizona's tough immigration law has sparked demonstrations by supporters and opponents.

Story highlights

The Obama administration says immigration is a federal role

Arizona says the federal government has failed, and it is helping

Key elements of the law have been blocked by a federal appeals court

Justice Elena Kagan will not hear the case

Washington CNN  — 

The Supreme Court has agreed to decide whether Arizona can enforce its controversial immigration law, over the strong objections of the Obama administration.

The justices made the announcement in a brief order Monday.

Federal courts had blocked key parts of the state’s Support Our Law Enforcement and Safe Neighborhoods Act, known as SB 1070. Arizona had argued illegal immigration was creating financial hardships and safety concerns for its residents and that the federal government has long failed to control the problem.

The administration has countered immigration issues are under its exclusive authority and that state “interference” would only make matters worse.

Arguments could be held in April with a final ruling by June. Justice Elena Kagan will not hear the case, since she had been involved in the administration’s initial legal opposition to the law as solicitor general, before taking the bench last year.

The possibility of a 4-4 split would prevent the four provisions of the law from going into effect, but not settle the larger constitutional questions.

Among the provisions blocked would be the requirement that local police officers check a person’s immigration status while enforcing other laws.

The Obama administration and immigration rights groups have opposed efforts to have local law enforcement apprehend and help deport illegal immigrants.

Although the specific question before the high court goes to the law’s enforcement, the justices could use the appeal to address the broader questions of its constitutionality. Similar laws – raising similar constitutional questions – are under challenge in lower courts in Georgia, Alabama, Utah, and South Carolina. Arizona’s appeal was the first to reach the Supreme Court.

Arizona Gov. Jan Brewer said she is confident the high court will rule for the state.

“This case is not just about Arizona. It’s about every state grappling with the costs of illegal immigration. And it’s about the fundamental principle of federalism, under which these states have a right to defend their people,” she said in a statement after the Supreme Court agreed to decide the matter. “Arizona has been more than patient waiting for Washington to secure the border. Decades of federal inaction and misguided policy have created a dangerous and unacceptable situation and states deserve clarity from the court in terms of what role they have in fighting illegal immigration.”

At issue is whether states have any authority to step in to enforce immigration matters or whether that is the exclusive role of the federal government.

Arizona argues it is merely assisting and cooperating with federal authorities, which it says Congress has blessed.

But the administration – backed by a variety of immigrant and civil rights groups – says allowing such state authority would hurt relations between the U.S. and other countries, disrupt existing cooperative efforts and unfairly target legal immigrants.

Earlier this year, a three-judge panel on the 9th Circuit Court of Appeals sided with the Justice Department and against Brewer.

U.S. District Judge Susan Bolton last year had temporarily blocked the law’s most contested parts a day before they were scheduled to go into effect. The appeals court ruling upheld Bolton’s ruling in April.

The legislation has a variety of supporters and detractors.

Republican lawmaker, Maricopa County, Arizona, Sheriff Joe Arpaio and other state governments were among those filing briefs with the appeals court supporting the law. The Mexican government, the Anti-Defamation League, the American Immigration Lawyers Association and the city of Tucson, Arizona, were among those filing briefs supporting the Justice Department’s side.

In its petition to the high court, Arizona says it is the nation’s busiest illegal entry point, with many people streaming in from neighboring Mexico.

“Arizona bears the brunt of the problems caused by illegal immigration. It is the gateway for nearly half of the nation’s illegal border crossings,” said state officials. “Beyond the obvious safety issues, the fiscal burdens imposed by the disproportionate impact of illegal immigration on Arizona are daunting. Arizona spends several hundred million dollars each year incarcerating criminal aliens and providing education and health care to aliens who entered and reside in the country in violation of federal law.”

Among the provisions given the go-ahead in April was a ban on “sanctuary cities,” or municipalities with laws or policies that render them relatively safe for undocumented immigrants.

Bolton’s ruling also allowed a provision making it illegal to hire day laborers if doing so impedes traffic. And her order allowed parts of the law dealing with sanctions for employers who hire illegal immigrants to take effect.

The appellate court sided with the Justice Department largely on the argument that federal immigration policy – as well as America’s standing in the world – would be greatly undermined if individual states adopted their own separate immigration laws. Doing so, the ruling contends, essentially means a given state is adopting its own foreign policy, one that may be in opposition to national policy.

“That 50 individual states or one individual state should have a foreign policy is absurdity too gross to be entertained. In matters affecting the intercourse of the federal nation with other nations, the federal nation must speak with one voice,” Circuit Judge John Noonan wrote in a concurring opinion.

The Arizona appeal could set important precedent on similar laws pending across the country.

In the first half of 2011, state legislatures in all 50 states and Puerto Rico have introduced a record number of bills or resolutions relating to immigrants or refugees, according to a report by the National Conference of State Legislatures. Through June, states had introduced 1,592 such bills or resolutions, compared to 300 in 2005.