CHARLOTTE, N.C. — Mitt Romney is portraying the outwardly calm President Barack Obama as a man seething with animosity and power lust as the Republicans seek to undermine one of the Democrat's greatest campaign strengths – his personal likability.

The president's re-election effort, Romney said Wednesday, "is all about division and attack and hatred." Obama, Romney added later while campaigning in Charlotte, is an angry man who "will do or say anything to get elected."

Whether by calculation or not, Obama highlighted his most genial side as he campaigned in Iowa, joking with voters about the pleasures of state fair junk food, and joshing with his wife, who made a rare campaign appearance with him.

"It all boils down to who you are and what you stand for," Michelle Obama told Iowans in Dubuque, on the final leg of the president's three-day bus tour of that toss-up state. "We all know who my husband is, don't we? And we all know what he stands for."

With polls showing Obama with a slight lead, Romney is focused on the "likability gap" that is evident in surveys that consistently show Obama ranking higher on general favorability questions than on handling the economy, which until now has been the Republican's chief focus. Romney's approach also comes as he and his running mate, congressional budget writer Paul Ryan, face increasing questions on a touchy economic issue for many Americans: their stance on Medicare.

While some GOP strategists question whether Romney's tactic will work, they agree that he is vulnerable among voters who find Obama more personally appealing. Romney and his allies appear bent on persuading voters that Obama is not what he seems.

Appearing Wednesday on CBS, Romney said the Obama campaign is "designed to bring a sense of enmity and jealousy and anger." The comments echoed the candidate's call on Tuesday for Obama to "take your campaign of division and anger and hate back to Chicago."

It's unclear whether Romney can convince voters that Obama is a politician of volcanic anger and ambition. Sometimes called "no-drama Obama," the president has disappointed liberal activists who see him as too dispassionate, meek and willing to compromise on issues such as a government-provided health insurance option.

Some GOP activists say Romney's time would be better spent talking about jobs and the economy, even if Obama has pitted wealthy Americans against the less-wealthy and allowed allies to level harsh charges against Romney.

"He is the most divisive president ever," said Virginia-based GOP consultant Mike McKenna. "But he doesn't seem angry, which is why he retains his personal popularity."

Republicans continued to complain Wednesday about Vice President Joe Biden's remarks earlier in the week in Danville, Va. Commenting in response to Republican criticism that the Obama administration had sought to regulate Wall Street too tightly, Biden told a crowd that included hundreds of black supporters that the GOP wanted to "unchain Wall Street." He added, "They're going to put y'all back in chains."

Republicans said Biden's remarks carried racial overtones and demanded that Obama condemn them. In an interview with People magazine Wednesday, Obama instead defended Biden, saying his running mate's only meaning was that consumers won't be protected if Wall Street reforms are repealed.

"In no sense was he trying to connote something other than that," Obama said.

Former Virginia Gov. L. Douglas Wilder, a Democrat and the nation's first elected black governor, lambasted Biden for the comments. In an appearance on CNN, Wilder called on the vice president to "cool it, back up" and admit that he was wrong.

Some Democrats saw potential racial allusions in the Romney campaign's bid to paint Obama as hate-filled. In his memoir, "Dreams From My Father," Obama wrote of trying to avoid looking like an "angry black man" as he came of age in mostly white America.

While Obama himself has not responded directly to Romney's stepped-up critique, his campaign had a quick rejoinder, calling Romney's remarks "unhinged." Campaign spokeswoman Jennifer Psaki said Romney has gone after Obama's record with ads on Medicare and welfare policy that "are full of bald-faced lies."

"It is hardly a campaign as Mitt Romney and his team have described," she said.

Matt Rhoades, Romney's campaign manager, said Wednesday that Obama "continues his campaign of rage and divisiveness," an apparent reference to Biden's comments and unrelated hard-hitting ads by a super PAC that supports the president.

Some Democrats found the tenor of such remarks unconvincing.

"They have a habit of overreacting to events," said Democratic consultant Jim Manley. The Romney team, he said, is using a sledgehammer "when a light touch would do" in trying "to take the president's favorability ratings down a notch or two."

As often happens in campaigns, the Republican message is multi-pronged, and possibly confusing to some voters. While Romney was using hot words like "attack and hatred" Wednesday, a super PAC that supports him – Americans for Prosperity – was airing a soft-touch TV ad in states including Ohio that lowered the temperature.

It shows former Obama supporters quietly expressing sadness and disappointment in the president's performance. One woman calls Obama "a great person," but says he has not earned re-election.

Still, the harsh tenor of much of the campaign has not gone unnoticed. An NBC-Wall Street Journal poll last month found that negative views of both candidates were on the rise and that 22 percent believed Obama was running a more negative campaign, 12 percent said Romney was being more negative and 34 percent chose both.

In Dubuque Wednesday, the Obamas addressed more than 3,000 people outside the red-brick Alliant Energy Amphitheater along the Mississippi River. The first lady vouched for her husband, calling him the "son of a mother who struggled" and the grandson of a woman who hit the glass ceiling at her job at a bank, watching as men she trained were promoted ahead of her.

Two rallies in eastern Iowa brought the popular first lady to her husband's side, creating a polite back-and-forth between the couple on stage. The health-conscious Mrs. Obama teased her husband about his recent trip to the Iowa State Fair, asking him if he had a "fried Twinkie," prompting the president to tell her that he had a "pork chop and a beer."

On an economic issue, Obama offered his most direct defense of his handling of Medicare, offering a point-by-point version of how the two tickets would handle the health care program for the elderly.

"I have strengthened Medicare," Obama said, saying his administration proposed "reforms that will not touch your Medicare benefits, not by a dime." He said Romney and Ryan wanted to "turn Medicare into a voucher program" while his approach had extended the life of Medicare by a decade. "Their plan ends Medicare as we know it," Obama said.

At a rally later in Davenport, in an apparent reference to Romney's criticism of Obama Medicare and welfare policies, the president complained that the Republicans "start making up all kinds of stuff about my plans."

In Charlotte, Romney repeated his claim that Obama would reduce Medicare benefits by $716 billion over 10 years. He did not mention that his running mate, Rep. Paul Ryan, has proposed the same savings, which are supposed to be realized through lower medical payments and great efficiencies in the program.

Some Romney surrogates expressed unease with the campaign's increasingly bitter tone. "This back-and-forth doesn't do either side or the country as well as it could," former Minnesota Gov. Tim Pawlenty said on CNN.

But Pawlenty added a dig at Obama, saying, "We have a president who won't even disclaim an ad that accuses Mitt Romney of killing a gentleman's wife." He was referring to a pro-Democratic super PAC's ad in which a widower says he and his wife lost their health insurance when his employer was taken over by a company Romney helped direct.


Associated Press writers Ken Thomas in Davenport, Iowa, and Julie Pace and Jim Kuhnhenn in Washington contributed to this report.

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