Will Obama challenge Romney in their second debate?

President Barack Obama's camp promised that the American public would see a more energized candidate on Tuesday night as Obama tries to keep Republican challenger Mitt Romney at bay in a high-stakes debate three weeks before Election Day.

Romney's campaign got a much-needed shot in the arm two weeks ago when he came out swinging in the first matchup between the two candidates, while Obama was widely criticized, including by his own supporters, for his passive response.

The strong debate performance helped Romney reverse his slide in the polls, and recent surveys put the race for the White House at a virtual dead heat just three weeks ahead of the Nov. 6 election.

Obama seems to have stemmed the bleeding though. In a Reuters/Ipsos daily tracking poll on Tuesday, he gained a bit more ground on Romney for the third straight day, leading 46 percent to 43 percent.

But a Gallup/USA Today poll also published on Tuesday showed Romney ahead of Obama by 4 percentage points among likely voters in the 12 battleground states.

Obama aides predicted a stronger showing in the second debate for the president, who has been in intense debate preparation for days, even cramming in an hour of homework as late as Tuesday afternoon.

"I think you'll see somebody who will be strong, who will be passionate, who will be energetic, who will talk about ... not just the last four years but what the agenda is for the future and how we continue to move ... our economy forward," Obama's senior campaign adviser, Robert Gibbs, said on MSNBC.

Romney also did some last-minute mock debate work, with Ohio Senator Rob Portman playing Obama.

The actual debate at Hofstra University in Hempstead, New York begins at 9 p.m. (0100 GMT Wednesday) and will last for 90 minutes. The audience of about 80 people was picked by the Gallup polling firm for being undecided local voters from New York state's Nassau County.

Format could be tricky 

Obama and Romney will have to deal with the more intimate town-hall format of this debate, which often inhibits political attacks as the candidates focus on connecting with the voters asking the questions.

Obama supporters panned their candidate for being too timid in the last encounter, but Romney aide Kevin Madden said it wasn't the Democrat's manner that was the issue.

"I think the problem didn't have anything to do with politeness. The problem is he doesn't have a record to run on," Madden told CNN.

Tuesday night carries an element of uncertainty as the candidates cannot predict the questions the audience of undecided voters might pose, which could range from tax policy to job creation to foreign policy.

"Almost all of the pressure will be on Obama this time, given how poorly he performed in the first debate and how much that seemed to help Romney and change the race," said political scientist Andrew Taylor of North Carolina State University.

The town-hall format lets the candidates "talk directly to people and look them in the eye and try to connect, which has not been a strength for either of them," Taylor said. "But you can still make strong points with a velvet glove."

The Reuters/Ipsos poll that gave Obama an edge showed the number of undecided voters had increased, indicating a drop of support for Romney among the coveted voting bloc.

During the first debate, Obama was widely criticized for not challenging Romney on exactly how he plans to give Americans a big tax cut without adding to the deficit, and for not calling attention to the switch to more moderate views Romney appeared to present during the matchup.

For Obama, the challenge will be to confront Romney on the issues without seeming nasty or too personal.

Romney, a wealthy former private equity executive often accused of failing to connect with ordinary people, would be happy with a steady performance to keep up his momentum.

Lines of attack 

The economy is expected to be a dominant topic. Obama is able to tout the latest jobs report, which showed that the unemployment rate dropped unexpectedly to 7.8 percent in September and reached its lowest level since Obama took office in January 2009.

Romney has countered that the labor market is not healing fast enough.

Glenn Hubbard, one of Romney's top economic advisers, told Reuters the Republican candidate was prepared to question Obama's record on the economy.

"His objective is to continue the conversation with voters about what the right economic policies are for the country," Hubbard said at an economic conference in New York. "He did that really well last time and I'd be stunned if he doesn't do it well tonight."

Romney will likely stay on the offensive over the administration's handling of diplomatic security in Libya before Sept. 11 attacks there that killed the U.S. ambassador and three other Americans. The debate comes a day after Secretary of State Hillary Clinton assumed responsibility for a lack of security that failed to protect against the deadly attack.

Romney may also focus on the Obama administration's subsidies for green energy, after another company - lithium-ion battery maker A123 Systems - filed for bankruptcy protection on Tuesday.

"A123's bankruptcy is yet another failure for the president's disastrous strategy of gambling away billions of taxpayer dollars on a strategy of government-led growth that simply does not work," Romney spokeswoman Andrea Saul said.

For their part, Democrats, hoping to shore up support with women voters, have hit Romney and his running mate, Paul Ryan, for their opposition to abortion rights.

The Gallup poll highlighted the importance of female voters, who traditionally prefer Obama. The poll showed Romney had pulled within 1 point among likely women voters.

The third and final debate will be next Monday in Boca Raton, Florida, and will focus on foreign policy issues.