WASHINGTON - President Obama's campaign so far is convincing a lot of independent voters that Mitt Romney is a cold-hearted, out-of-touch rich guy.

Obama's engaging in an age-old election-year summer tradition - define your lesser-known opponent in as horrid a manner as possible. It usually works, staggering challengers such John Kerry in 2004 and Bob Dole in 1996.

And it affects the campaign narrative - instead of focusing on Obama's stewardship of the struggling economy, Romney in recent days has had to battle accusations about his own record in business.

Romney vigorously disputes accusations that he misled people about when he really left investment firm Bain Capital, and independent fact-checkers have found the allegations have little merit. But Obama's ability to raise doubts about Romney's role at Bain have a larger goal: taking Romney's perceived strength - that his business record gives him the know-how to create jobs - and turning it into a weakness of big business and out-of-touch wealth.

Independent voters are notably wary of Romney. A July 9-10 Gallup poll found 19 percent were less likely to vote for the Republican presidential candidate because of his wealth. And that was before the torrent of ads and criticisms from Obama.

"Enough Americans generally and independents specifically say Romney's wealth makes them less likely to vote for him that it could in theory make a difference at the margins in some key swing states," a poll analysis found.

Romney has fought back hard, telling ABC News that Obama "sure as heck ought to say that he's sorry for the kinds of attacks that are coming from his team." His campaign has run ads protesting the accusations and insisting that "there was 'no evidence' that Mitt Romney shipped jobs overseas."

But here's Romney's problem: The Bain battle has dominated political talk, obliterating his efforts to talk about his economic remedies. And among some Republicans, it's raised questions about the former Massachusetts governor's ability to take a punch and control the campaign narrative against a master campaigner.

History shows such tactics can work. In the summer of 1996, President Clinton ran ads tying Republican candidate Dole to the highly unpopular Newt Gingrich, then speaker of the House of Representatives.

Eight years later, "Swift Boat Veterans for Truth" raised questions about Democratic presidential nominee Kerry's Vietnam War service.