WASHINGTON (AP) — Backed into a corner by border state Arizona’s tough new immigration law, Democrats and Republicans alike find themselves grappling with a volatile issue neither party wanted to fight over just before U.S. congressional elections in November.

As lawmakers learned during the last national debate on immigration, in 2007, the issue incites passions across the U.S., affecting everything from national security to states’ rights to racial ambitions and resentments. It is fraught with political minefields.

Thus, President Barack Obama, the Democrats who control Congress and Republicans who are in the minority are doing a delicate dance, mindful not to anger their electoral bases — or independents — on the issue.

Underscoring the careful maneuvering, Homeland Security Secretary Janet Napolitano tried to strike a balance in testimony to Congress on Tuesday, saying, “Continually enhancing border security is not only critical for border communities, but is a necessary part of any comprehensive attempt to fix our nation’s broken immigration system to make it work for the 21st century.”

Immigration touches every rung of American politics, from security issues like border control and terrorist profiling to domestic affairs like education and health care. American cultural issues like race, class and language also are in play. And every level of government, from federal agencies to town councils, is trying to deal with immigration issues.

That means businesses, labor unions, religious groups, immigrant advocacy organizations and other interests all have a stake — and all are likely to hold candidates accountable in the elections.

Republicans, hoping to make inroads with the fast-growing Hispanic population, are wary of being portrayed as xenophobic. Democrats fear the characterization that they are weak on national security.

“This really sort of throws down the gauntlet for both parties,” said Catherine Lee, a Rutgers University sociology professor focused on immigration reform politics. She said it’s too early to say which party will benefit from immigration reform being out front. “That will depend on how the parties handle the issue and frame the debate going forward.”

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Already, immigration is emerging as a major issue in a slew of Republican primaries, with House, Senate and gubernatorial candidates, including Arizona Gov. Jan Brewer, having to choose between a hard-line approach and a more middle-of-the-road solution. The Republicans also now face the sensitive task of figuring out how to appeal to their conservative base and tea party activists without further turning off Hispanics and other swing voters.

Brewer, in the midst of a tough Republican primary battle, signed a law requiring police to question people about their status if there’s reason to suspect they’re in the country illegally.

Arizona Republican Sen. John McCain, who worked with the late Sen. Edward M. Kennedy, a Democrat, on reform efforts, said Tuesday that Arizona had to pass a strict law because the Obama administration has failed to “secure our borders.”

McCain is facing a difficult Republican primary challenge and has adopted a hardline stance on illegal immigration. He once championed an eventual path to citizenship for the nation’s 12 million illegal immigrants.

Obama, a Democrat, has instructed the Justice Department to examine the Arizona law that he said threatens to “undermine basic notions of fairness.” He also has pressed anew for national immigration legislation, saying, “If we continue to fail to act at a federal level, we will continue to see misguided efforts opening up around the country.”

Protests against the Arizona law erupted overnight, and the political battle lines were quickly drawn.

Conservatives applauded the measure as necessary to stop a flow of illegal immigrants from Mexico. Liberals decried it as a threat to civil rights. The Roman Catholic cardinal in Los Angeles compared the law’s rules to Nazism.

Since Brewer signed the measure, Republicans and Democrats in Washington have largely focused on the process of taking up immigration reform and shied away from talking substance.

Senate Majority Leader Harry Reid, in his own tough re-election fight in Hispanic-heavy Nevada, swiftly renewed his promise to pursue immigration legislation even as the Senate works on measures on financial regulatory reform and climate change. That prompted Republican Sen. Lindsey Graham, who backs comprehensive immigration reform, to threaten to withhold his support for the climate bill if Senate Democrats opt to deal first with immigration.

“We have an enormous number of people who are in this country illegally,” said Senate Minority Leader Mitch McConnell Still, he added, “It’s not a great time to take this issue up in Washington.”

But Sen. Chris Dodd, a Democrat, called the Arizona law “outrageous” and said, “Before this even gets further out of hand, we’ve got to step up and do the job.”

Inroads that Republicans made among Hispanics during George W. Bush’s presidency were erased following the failed 2007 effort to overhaul the immigration system. Bush, a Texan who focused heavily on Hispanics, got 44 percent of the Hispanic vote in 2004. But Republican McCain, whose presidential campaign that year was derailed in part because of his support for comprehensive immigration reform, got only 31 percent four years later.

For their part, Obama and the Democrats who control Congress were all but forced by Brewer’s action to bring up legislation sooner than expected. Hispanics will be closely watching to see if Obama delivers on his reform promise; passage could solidify their support for the Democratic Party.

Democrats will have to walk a fine line, appeasing liberals without angering other voters, including tea party activists and conservatives who put a high premium on states’ rights. Moderate Democrats in vulnerable states and districts will have to take sides, and they could well thwart the White House to save their own jobs.

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