Call it the built-in gravitas gap: President Obama flies the country in a grand 747, cruises in plush limousines adorned with American flags, and speaks from the White House Rose Garden, while his campaign opponent, Mitt Romney, flies in a smaller MD-83 passenger jet, rides in nondescript SUVs and makes speeches at factories and strip malls.

But on Wednesday that gap is closed, even if just for 90 minutes, when voters see the two men stand on the same stage together and go head-to-head in the first presidential debate of the campaign.

“Debates are an equalizer for challengers because there are no office trappings on stage,” said Darrell M. West, director of Governance Studies at the Brookings Institution. “It is two people answering questions, and voters can reach their own impressions without outside filtering.”…

“It is the only chance to go toe to toe with the incumbent and look just as presidential as he can,” Mr. Sabato said.

Romney’s advisers have a simple strategy: They want their candidate to balance his finely tuned arguments with personal warmth. Since Romney is a reserved man, his advisers acknowledge that it will be difficult for him to endear himself to the country, especially under the hot studio lights. But they consider it critical. “This is really about introducing him to the country,” a Romney adviser says. “It’s the largest audience he has ever had. Everybody’s watching.”

During prep sessions in Vermont this past month, Romney has worked tirelessly on the stylistic aspect of his presentation, and Romney’s advisers predict that the former Massachusetts governor will come across as both presidential and empathetic. Rather than fire off brusque retorts, as he often did during primary debates, Romney will take care “to speak in paragraphs about the economy,” a second aide says…

But it won’t all be warm and fuzzy. That’s where the balance comes in, advisers say. When he has the opportunity to give a full response, look for him to speak directly to the camera, making his case. When the president knocks him, however, Romney won’t try to stay above the fray, and he’ll try to make sure that his answers are more than clinical prescriptions. Romney will never be as gregarious as Bill Clinton or a great communicator like Ronald Reagan, but his advisers think he can score if he is comfortable and assertive.

“You’ll see a little combativeness,” says former New Hampshire governor John Sununu, a longtime Romney friend. “Remember, though, that there will be more to this debate than telling the president to stick a bumper sticker on his forehead. This is about getting the people who are watching to look at their televisions and say, ‘My gosh, that’s the guy this country needs to be president.’”

In the desperate battle to shape public expectations over Wednesday’s presidential debate in Denver, Gov. Mitt Romney appears to be winning-by-losing.

Most prospective voters expect him to lose the face-to-face debate, so he has a greater opportunity to surprise and reassure voters who might switch support from President Barack Obama to the GOP candidate.

“The best news for Romney going into the debates is that voters have very low expectations for him and therefore the bar for him to change some minds is set lower than it is for the president,” said a survey released Oct. 2 by Quinnipiac University.

There would be two GOP debates in Florida, one in Tampa and one in Jacksonville. Coming off defeat in South Carolina, Romney had to raise his game.

He did. Particularly in the Jacksonville debate, Romney seemed like a new man. He deftly and confidently ripped Gingrich over accusations that Romney had investments in Fannie Mae and Freddie Mac, and then ran circles around Gingrich on immigration. With nearly everything at stake, and big audiences watching in the biggest primary state, Romney shone…

Romney’s biggest challenge, as Gingrich sees it, is to deal with what Gingrich believes will be Obama’s repeated misrepresentations of Romney’s record and position. Back in January, Gingrich believed Romney misrepresented Gingrich’s own record, something he still believes today. “Now, Romney has to figure out with Obama what I failed to figure out with Romney,” Gingrich says. “How do you convince the audience that the plausible thing just said by your opponent is factually false?”…

The most important thing Romney could do for himself is to remember that feeling from the night he lost South Carolina, when he realized that everything was riding on his next performance. This time, it is.