CHARLOTTE, N.C. – Mitt Romney is portraying the outwardly calm President 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 on CBS Wednesday, 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.

At the same time, 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 the stepped-up critique, his campaign had a quick rejoinder, calling Romney’s remarks “unhinged.”

Matt Rhoades, Romney’s campaign manager, said Wednesday that Obama “continues his campaign of rage and divisiveness.”