PARMA, Ohio — Lest anyone forget the importance of Ohio's white, working-class voters, President Barack Obama sent a clear reminder on Thursday.

Make that two reminders: Bill (Clinton) and The Boss (Bruce Springsteen), two aging baby boomers still at the top of their game.

"No retreat, believe me, no surrender," Springsteen sang, performing without the backing of his E Street Band in a darkened gymnasium lit by a spotlight. The lyrics seemed aimed both at the president and his supporters.

With less than three weeks until Election Day, Clinton and Springsteen took the stage to rally support for Obama among the critical middle-class voting bloc in this tightly contested Midwestern swing state.

"For 30 years, I've been writing about the divide between the American dream and the American reality," Springsteen said. "Our vote is the one principal way we get to determine that distance."

Clinton implored voters to reward Obama for bailing out the auto industry, which has deep roots in Ohio.

"When you were down, you were out, and your whole economy was threatened, the president had your back," said the former president and a top surrogate for Obama.

Ohio is at the center of both Obama and Republican Mitt Romney's campaign strategies. Winning the state would put Obama on the brink of the 270 Electoral College votes required to win the White House. Romney, who has fewer pathways to victory than the president, almost certainly needs Ohio's 18 electoral votes if he hopes to claim victory.

Both campaigns are paying special attention to Ohio's working class – many of whom are white and don't have a college degree. They've made up about half of voters in the state in each of the last two presidential elections.

And they were well-represented among the 3,000 people packed into a community college gymnasium for the Clinton-Springsteen appearance.

"I think Clinton is key," said firefighter Matt Sparling of Parma Heights, Ohio. "He's got an amazing way of keeping it simple." Springsteen, he added, helps draw the crowd.

As Ohio officials opened the event, some in the crowd bellowed "Bruuuuce" – a standard fan shout-out to the musical legend.

Clinton, too, reveled in the chance to serve as Springsteen's opening act.

"I am qualified because I was born in the U.S.A. and unlike one of the candidates for president, I keep all my money here," Clinton said, referring both to one of the rocker's classic songs and Romney's overseas financial holdings.

Polls show Obama with a lead in Ohio, but Romney has made gains following his strong performance at the first presidential debate.

Each candidate has struggled to connect with white, working-class voters, in Ohio and elsewhere.

Nationally, Romney holds a strong edge among white voters with jobs and no college degree. But his advantage is narrower in union-heavy Ohio. A recent NBC News/Wall Street Journal/Marist poll showed Romney ahead 51 percent to 44 percent among likely noncollege, white voters.

Those heavily-courted voters backed Republicans in the past two elections.

In 2004 in Ohio, 55 percent of white voters without a college education voted for Republican George W. Bush and 44 percent voted for Democrat John Kerry. Four years ago, they voted for Sen. John McCain, R-Ariz., over Obama 54 percent to 44 percent.

This time around, Obama's team sees opportunities to increase its levels of support.

The campaign has blanketed the state with television advertisements portraying Romney as a corporate raider who moved manufacturing jobs overseas. The state's 7.2 percent unemployment rate is more than a half-point lower than the national average. And the auto bailout is credited with saving thousands of jobs in the state.

"I'm thankful GM is still making cars," said Springsteen, whose songs often reflect the stories and values of the people who work in places like auto factories. "What else would I write about?"

Clinton stayed in Ohio on Thursday for another campaign rally, while Springsteen headed to Ames, Iowa, for a second appearance on Obama's behalf.

In addition to that stellar duo, Obama is relying on Vice President Joe Biden to rally support among white working-class voters. Biden, raised in a middle-class family from Scranton, Pa., has been a frequent visitor to Ohio. He's scheduled to make a three-day swing through the state next week.

Romney has also relied on his running mate for help in Ohio. Rep. Paul Ryan, a Wisconsin native, has put his Midwestern sensibilities to use, dropping by college football tailgates and a Cleveland Browns practice. Ryan is due back in Ohio on Saturday.

Springsteen, an avid supporter of Obama in 2008, had planned to sit out this election. He never explained exactly what changed his mind in the campaign's closing weeks, saying only that he believes Obama understands the struggles of "everyday citizens."

The rocker kept his comments brief during a six-song set, which included "Youngstown", a song about the economic woes of the Ohio city. Seeking to hew a bit more closely to Obama's re-election message of shared prosperity, he also played a newer song that has become a staple at the president's campaign rallies.

"Wherever this flag is flown," Springsteen sang. "We take care of our own."

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Associated Press writer John Seewer in Parma and AP Deputy Director of Polling Jennifer Agiesta in Washington contributed to this report.

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Follow Julie Pace at http://twitter.com/jpaceDC

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