DES MOINES, Iowa -  On his first visit back to the Iowa state fairgrounds since the 2008 campaign, President Obama tonight used a grassroots rally to launch sharp new attacks against rival Mitt Romney over the debt and deficit and vigorously defend his own handling of the same.

The venue holds symbolic value for Democrats because it was here, in August that Romney made his now-famous declaration that "corporations are people, my friend."

Obama thrust the Republican candidate's unflattering moment front and center early on.

"The worldview that Gov. Romney gained from his experience as a financial CEO explains something. It explains why the last time he visited these same fairgrounds, he famously declared 'corporations are people,'" Obama said, drawing loud boos from the crowd of 2,500.

"That's what he said, that's what he called them," Obama added. "It also explains why, when a woman right here in Iowa shared a story of her financial struggles, he gave her an answer out of an economics textbook.  He said, 'Our productivity equals our income.'

"Let me tell you something: We believe in the profit motive. We believe that risk-takers and investors should be rewarded. That's what makes our economy so dynamic. But we also believe that everybody should have opportunity."

Ahead of the event, Obama's re-election campaign circulated a video of Romney's Iowa State Fair remarks, all aimed at bolstering their claim that the former private equity executive was a wealth-seeker who put investors' interests ahead of the middle class.   Several of the campaign's major, multi-state TV ad buys - each of which have included Iowa - have touched on the same theme.

Obama offered his most spirited attacks on Romney over his claims about the burgeoning federal debt and record-high deficits that have been incurred over the past three and a half years.

"They've got the nerve to go around saying that they're somehow going to bring down the deficit," he said, referring to Romney's budget blueprint. "Economists who've looked at his plan say it would swell our deficits by trillions of dollars, even with the drastic cuts he's called for [on] things like education, agriculture and Medicaid.

"He promises to do that on day one," Obama added, referring to the new Romney TV ad by the same name.  "We don't need that. That's going backwards. We're going forwards."

"Forward" is Obama's re-election campaign slogan.

Romney, on his most recent visit to Des Moines earlier this month, argued that Obama has presided over a "prairie fire of debt," and told voters, "Every day we fail to act we feed that fire with our own lack of resolve."

His campaign and the Republican National Committee have also stressed that during Obama's first term, $5 trillion was added to the debt, which now exceeds $15.6 trillion.

"A president who broke his promise to cut the deficit in half by the end of his first term has no standing when it comes to fiscal responsibility. By the end of this year, President Obama will have presided over a record-shattering four consecutive trillion-dollar deficits and added an historic amount to our national debt," said Romney spokesman Ryan Williams.

"When you listen to President Obama's campaign speeches, it's as if he's forgotten that he's been president for nearly four years and has a record to defend. President Obama has proven beyond all doubt that he is not serious about fixing our country's spending problem."

Offering a rebuttal tonight, Obama said that his administration has taken fiscal issues seriously, attributing high deficits to the "depth of the recession." He said Romney's claims were divorced from reality.

"I know Gov. Romney came to Des Moines last week worried about a 'prairie fire of debt.' That's what he said: 'Prairie fire,'" Obama said. "But, you know, he left out some facts. His speech was more like a cow-pie of distortion."

"I don't know whose record he twisted the most, mine or his," he added.

Obama argued that the pace of federal government spending during his tenure has been the slowest of any president in 60 years.

"By the way, it's like the Republicans run up the tab and then we're sitting there and they've left the restaurant," he said. "Why did you order all those steaks and martinis?"

The president said Romney's budget - which includes new tax cuts for wealthier Americans - would not be the deficit slayer he claims it would be.

"Oh, by the way, something else he hasn't told you is how he'd pay for a new $5 trillion tax cut," Obama said.  "That's like trying to put out a prairie fire with some gasoline."

Obama claims his plan would cut the deficit by $4 trillion over 10 years through a combination of spending cuts and tax hikes.