DES MOINES, Iowa -- President Barack Obama delivered his harshest rebuttal yet to rival Mitt Romney on Thursday, dismissing his challenger's claims as "a cow pie of distortions" as he sought to rekindle the all-but-faded Iowa magic that launched him in 2008.
Escalating his criticism of Romney's background as a venture capitalist, Obama said it wasn't adequate preparation for the presidency.
"There may be value for that kind of experience, but it's not in the White House," Obama said.
The speech, to a cheering Iowa crowd of about 2,500 at the Iowa State Fairgrounds, represented a new intensity for Obama's campaign as Romney begins to hit his stride carrying the Republican standard. Iowa, soured by the direction of the nation and its economy, has drifted away from Obama since his 2008 caucus victory over Hillary Clinton made him the Democratic front-runner.
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While Obama carried the state in the general election by a comfortable margin that year, polls this year have shown voters narrowly preferring Romney, who plans to wage his own major effort in Iowa.
Obama pointedly chose the turf where Romney, the presumptive Republican nominee, once declared that corporations are people. Obama said Romney would roll back regulations and return to policies that he said helped create the recession and would increase government deficits.
Last week, Romney said Obama had created "a prairie fire of debt."
On Thursday, Obama said Romney's tax plan is "like trying to put out a prairie fire with some gasoline."
In a statement issued after the speech, Romney spokesman Ryan Williams said, "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."
Obama's visit to Iowa underscored his vulnerability with working-class voters and his effort to identify with the middle class.
Earlier, in blue-collar Newton, once the prosperous headquarters of Maytag appliances, Obama visited a wind turbine plant to push his alternative-energy agenda and delivered a message that could as well have applied to all of Iowa. "Yeah, we're facing tough times, but we're getting through them. We're getting though them together," he said.