If you believe the polls, it would appear there is one big factor standing in the way of Mitt Romney being elected president: Americans don’t like him as well as they do Barack Obama.

That was confirmed again in a new USA Today-Gallup survey in which respondents gave Romney higher marks on the economic issues, which voters say they care most about this year. But President Obama crushed Romney — 60 percent to 30 percent — on the question of which of the two was more likable.

In April, a Washington Post-ABC News poll found an even larger gap, with 64 percent of those surveyed describing Obama as the friendlier, more likable candidate, and only 26 percent saying that about Romney.

“We’re not going to win a personality contest. It’s not an election for class president. It’s who can best solve the problems of the country,” said Romney’s pollster, Neil Newhouse. “Likability isn’t fixing the economy or helping the middle class make ends meet.”

In part, the disparity reflects a natural reserve, even an awkwardness on Romney’s part. It also reveals a sensitivity to the fact that there are upsides and downsides politically to defining himself through his biography — his Mormon faith, his spectacularly successful business career, his wealth and his stint as the governor of a liberal state.

Asked last week by NBC News’s Brian Williams whether he is “unknowable to us,” Romney insisted that he is trying and still has opportunities to introduce himself.

“You know, I’ve been on ‘The Tonight Show’ and ‘Letterman’ and ‘The View,’ and I do some of those things to get better known,” he said in the interview that was broadcast Wednesday. “But at the same time, most folks won’t really get to see me until the debates and will get a better sense of the character that I have.”

Romney also seemed to acknowledge that he is not exactly a natural when it comes to selling the inner Mitt. “My wife and my sons and daughters-in-law, they’re doing the best job they can to get the real story about who I am in public view,” he said.

In every presidential election for the past two decades, the candidate viewed as more likable was the one who won.

Voters look at the ballot with the expectation that they are going to have “a pretty intimate relationship with the president,” said Obama’s chief political strategist, David Axelrod. “In addition to everything else, they know they are going to see a lot of him.”

But Axelrod added: “Likability is a hard thing to measure.” Indeed, Obama himself is no one’s idea of a glad-hander.

What makes people warm up to a candidate, Axelrod said, is a sense that he is “someone who is accessible to me, someone who understands me, someone I can relate to.”

Those perceived qualities about the president, strategists on both sides say, have helped keep the race close, despite Americans’ disappointment with how the economy has performed under Obama.

“Likability is keeping Obama in the game at this point,” said Mark McKinnon, a top strategist for George W. Bush, who in his 2004 presidential reelection bid was famously deemed in one poll to be the candidate with whom undecided voters would rather have a beer (an irony, for a teetotaling president).

“But Romney has a lot of potential to improve his likability numbers, particularly during the convention,” McKinnon added. “Romney hasn’t really revealed much of his personal story or his personality, so he’s got a lot more potential to grow.”

Romney did not do much to up his affability quotient on his London trip.

The campaign had hoped Romney’s appearance there would reprise one of the most glorious chapters of his biography, his role in rescuing the scandal-ridden 2002 Winter Olympic Games, in Salt Lake City.

Instead, the presumptive Republican presidential nominee played the party pooper, raising doubts about security at the London Olympics, which drew public rebukes from Prime Minister David Cameron and London Mayor Boris Johnson.

While Obama’s visit to the city as a candidate four years ago had throngs of Londoners chanting “Yes, we can,” Romney’s got a screaming headline Friday in the tabloid Sun: “Mitt the Twit.”

GOP strategists within and outside the Romney campaign insist that the former Massachusetts governor still has plenty of time to acquaint the American people with his softer side, and that, given all the problems the country faces, personality will not be the deciding factor this election year.

Those assumptions show in Romney’s advertising. The standard playbook for challengers is to launch their campaigns with a round of biographical ads. Romney’s first spots after securing the nomination focused on what he would do on “Day One” of his presidency.

“Personal qualities are taking a back seat,” Newhouse said. “What voters are asking us is, ‘What’s he going to do? How is he going to be different? How is he going to lead us out of this mess?’ ”

Sounding a bit like a sympathetic psychotherapist, a recent Republican National Committee ad acknowledged Americans’ affection for Obama and offered them permission to move on.

“He tried. You tried,” the announcer said. “It’s okay to make a change.”

Meanwhile, the Obama campaign has tried to take advantage of a void that Romney has created by his failure thus far to fill in the picture of himself.

It has pounded him with ads that depict him as heartless, privileged and secretive. In an exercise of jujitsu, Obama’s attacks focus on the very aspect of Romney’s résumé that he has highlighted as his greatest strength: his business career.

“Who has owned the Mitt Romney biography? It’s been the Obama campaign that has defined Mitt Romney,” said Steve Schmidt, a veteran Republican strategist who helped run GOP nominee John McCain’s campaign in 2008. “A lot of criticism people make is that Mitt Romney hasn’t revealed a lot of himself in terms of who he is.”

That will change, Newhouse vowed, noting that the Republican convention, at the end of August, offers a “tremendous opportunity.”

“We’ve only scratched the surface in telling the Mitt story so far,” the pollster said. “We are not going to miss the opportunity to do that.”

Romney is starting to make an effort, as well, although his narrative is still a work in progress.

“I’m very proud of my heritage. I’m a member of the Church of Jesus Christ of Latter-day Saints. I’m proud of that. Some call that the Mormon Church. That’s fine with me. I’ll talk about my experiences in the church. There’s no question they’ve shaped helped shape my perspective,” he said in his NBC interview. “I have, like my wife, we try and give about 10 percent of our time, not just 10 percent of our money, but also of our time, to service in the community. Those things have enriched our life, have given us perspectives that go beyond the group of friends we might have otherwise had.”

As uncomfortable as it may make him, the public will ask — indeed, demand — that Romney show more and more of that side of his life.

“There’s much to admire about Mitt Romney, and part of the process of running for president is it requires you to open a window into your soul. The American people want to see the president three-dimensionally,” said Schmidt. “The decision about whether you’re going to talk about those things is made in the decision to run for president.”

Peyton M. Craighill contributed to this report.