Even as donors and party leaders coalesce behind Mitt Romney, the probable Republican presidential nominee is having a hard time getting voters to like him.

The latest Washington Post/ABC news poll finds that 35 percent of Americans have a favorable opinion of Romney while 47 percent view him unfavorably, a gap that represents the first time since 1984 that a likely presidential nominee registered a negative favorability rating in the Washington Post/ABC News Poll.

By contrast, President Obama is viewed favorably by 56 percent of Americans. He is easily outpacing Romney among women, only 27 percent of whom view rhe Republican candidate favorably, a rating that is consistent with recent polls showing Obama opening a substantial lead among female voters.

A CNN/ORC International poll released on Monday also underscored Romney's lack of personal appeal. Voters chose Obama over Romney by wide margins when asked which candidate seemed more likeable, honest and willing to stand up for his beliefs. But the two men were essentially tied on the question of who could revitalize the economy, seeming to validate Romney's strategy of touting his business acumen.

In the same poll, about three quarters of Obama supporters said they were casting a vote for the president, while about two thirds of Romney backers said they were voting against Obama -- showing, as Republican primary exit polls have, that Romney's allure lies more in his perceived ability to unseat President Obama rather than in his charisma or conservative bona fides.

Romney has struggled throughout the race to bolster his likeability. A February poll found that voters liked him less the more they learned about him, although respondents to that poll also said they trusted his ability to manage the economy and tame the budget deficit.