WASHINGTON - With a divisive new law in Arizona providing the kindling, the national debate over immigration has reignited, as Democrats and Republicans in Congress appeal to their political bases ahead of November's elections.

It's unclear, however, whether Congress and the Obama administration are prepared to act on the issue or just talk.

President Obama on Friday called Arizona's law "misguided." Obama said the measure showed why Congress needed to pass a national immigration overhaul soon. "If we continue to fail to act at a federal level," the president said, "we will continue to see misguided efforts opening up around the country."

Obama, at a naturalization ceremony for members of the U.S. military, said the Arizona legislation threatened "to undermine basic notions of fairness that we cherish as Americans, as well as the trust between police and their communities that is so crucial to keeping us safe."

He said he'd instructed his administration, including the Justice Department, to study the law's impact on U.S. citizens' civil rights.

On Capitol Hill, however, the legislative agenda already is packed through the summer, and fitting in something as controversial as immigration appears unlikely.

Polls find that most Americans want their leaders to focus on the economy and jobs. However, Hispanics, the fastest-growing group of voters, want action on immigration.

Senate Majority Leader Harry Reid, D-Nev., who is in a tough re-election battle, has told immigration advocacy groups that he thinks Congress will take up immigration this year. Hispanics are a large voting bloc in Nevada.

Democratic leaders in the House of Representatives don't seem as eager as Reid is to tackle immigration, however. They say privately that House Democrats have endured enough tough votes on thorny issues and aren't prepared to deal with one that could become a wedge in November.

House Majority Leader Steny Hoyer, D-Md., on Thursday shot down reports that Democratic leaders had reached agreement that addressing immigration was a greater priority than an energy bill was.

"I don't know that anybody made a determination in the discussions I have with leadership that immigration is more important than energy," Hoyer said, adding: "I am not sure the Senate can move an immigration bill."

White House press secretary Robert Gibbs dismissed the notion that immigration is too politically risky this year.

"I'm sure sending 30,000 troops to Afghanistan is a risky political thing, but it's the right thing to do," Gibbs said. "It's a politically risky thing to make sure that two auto companies don't go under, causing a million jobs to be lost, but it was the right thing to do.

"The president was elected to do the right things, not just to do what was politically easy."