meet Tuesday in their second debate just 21 days before the election.
In their first clash, nearly two weeks ago, Obama mystified Democrats with a limp defense of his White House term and failed to frame a compelling vision of why he deserves a second.
Avoiding Romney's eye and lacking fire, Obama dismayed supporters with one of the weakest showings since the first televised presidential debate in 1960.
It was left to Vice President Joe Biden to stem some of the panic when he faced Republican vice presidential pick Paul Ryan last week, showing combative flair and conviction the president lacked.
Biden hammered Romney's biggest liabilities, including a secretly filmed tape in which he branded 47 percent of Americans as "victims" and also brought up the low tax rate Romney pays on his fortune.
Obama, guarding presidential dignity, will not be as brash, but is under pressure to show more stomach for the fight against an opponent enjoying his best streak of the campaign.
The town hall style format of Tuesday's debate at Hofstra University, New York, may help, requiring him to interact with an audience and by extension viewers at home.
Michael Kramer, professor of communication studies at St Mary's College, Indiana, said Obama must stress eye contact, after spending much of the Denver debate glancing down at his notes.
"He needs to make sure he is talking right to the people asking the questions and really engaging them and being more dynamic ... he needs more energy in his voice," Kramer said.
But Obama must also be careful not to over compensate by being too aggressive, Kramer said.
Republicans are already laying groundwork for such a slip.
"I think President Obama is going to come out swinging. He's going to have to compensate for a poor first debate," Republican Senator Rob Portman told ABC.
Privately, Obama aides said it took less than a quarter of an hour for them to realize in Denver that their boss was off kilter, but are confident he will bounce back.
Obama advisor Robert Gibbs said the president was "disappointed" in his performance in Denver.
"He knew when he walked off that stage and he also knew as he watched the tape of that debate that he has to be more energetic," Gibbs told CNN.
"I think you'll see somebody who is very passionate about the choice that our country faces."
Supporters expect Obama to raise not just Romney's 47 percent comment, but also his own auto industry bailout and women's issues, which he ignored in Denver and to answer Romney's complaints he mishandled the attack on the US consulate in Benghazi on September 11.
The huge audience for the Denver debate meant Obama's embarrassment was a ubiquitous topic of conversation in America, and some people wondered whether the president was simply exhausted by four crisis-scarred years.
Conservatives saw vindication.
National Review columnist Charles Krauthammer said Romney had engineered the "biggest rout since Agincourt" and asked "Can this be the hip, cool, in-control guy his acolytes and the media have been telling us about?"
Critics said Obama was exposed as unused to cross examination after four years in the White House bubble and was disdainful of others and his Rocky Mountain low in Denver wrought swift political damage.
Romney overtook the president in national polls and undermined him in battleground states that will decide the election.
The Obama who showed up in Denver, a sometimes detached figure who chafes at the trivialities of day-to-day politics, was familiar to people who have seen him at close quarters, but television viewers met him for the first time in Denver.
Aides say the president hates artifice and he appeared to bristle at the fake gladitorial nature of a debate against a foe he disdains.
During a mostly charmed political life, Obama has sometimes stumbled into similar trouble, only to rescue himself with a grand political gesture.
In December 2007, he seemed to be meandering to defeat to Hillary Clinton in Democratic primaries.
But with an electrifying speech at an Iowa Democratic party dinner, the president revived his campaign.
When racially charged rhetoric of his pastor Jeremiah Wright, threatened to derail his White House hopes: Obama produced a seminal speech on race.
As president, Obama dragged health reform through Congress after a passionate rallying call to Democratic lawmakers, then bounced back from a Republican rout in 2010 mid-term elections and seemed poised for re-election.
But on Tuesday he will not been in his rhetorical comfort zone making a speech, but in the treacherous high wire act of a televised debate.