After losing ground to Republican Mitt Romney following a sluggish performance in the first presidential debate, U.S. President Barack Obama faces a serious challenge to put his re-election bid back on track when the two men face off on Tuesday for round two.

Many Democrats were disappointed with Obama's cautious, lackluster demeanor in the long-awaited showdown in early October, while Romney's strong performance gained him new supporters and reinvigorated the Republican campaign.

Caroll Doherty, associate director of the Pew Research Center, called it a "substantial victory" for Romney, who showed a four point lead among likely voters in a poll conducted over four days after the debate.

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Romney, who appeared more assertive and focused, delivered a scathing critique of Obamas economic policies and said Obama had not done enough to lead the country out of the economic downturn.

At one point while Romney admonished Obama for the high rate of unemployment among Americans, citing "23 million people out of work," Obama seemed to just listen passively, and often looked down at his lectern.

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Rather than mounting an aggressive counter attack against Romney's policies as expected, Obama missed several crucial opportunities to press him on significant issues such as his suggestion to let U.S. automakers go bankrupt, his proposal to let struggling homeowners lose their houses, and what was seen by many as a blatant dismissal of 47 percent of the public as unproductive parasites.

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One potential talking point for Obama: a Labor Department jobs report showing the unemployment rate dropped by 0.3 percentage point in September to 7.8 percent - its lowest since January 2009.

Doherty said the job numbers would definitely help Obama in the next debate, but questioned whether the numbers are really "factored into voters decision or not."

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Despite Romney's recent gain in the polls, some voters are still wondering about the details of Romney's policies, particularly his tax plan, according to Doherty.

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On the campaign trail over the last week, Obama seemed confident and may have begun to provide a glimpse of his strategy for the next debate. Obama accused Romney of recanting on the tax plan he had been "pitching for more than a year" which included tax cuts for the rich.

Obama also accused Romney of pandering to middle class voters by recasting his views on programs like Medicare and the Affordable Care Act, widely referred to as "Obamacare."

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Campaign advisers to Obama promised on Sunday that he would be more aggressive and energetic in his second debate against the Republican challenger.

Indeed, the next debate, a "town hall" at Hofstra University in Hempstead, New York, may play more to Obama's strengths on the campaign trail, where he seems to connect well with supporters.

But the setting of the next debate might also be a wild card for the two rivals, according to Caroll Doherty.

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Although the debate will be moderated by CNN's Candy Crowley, both candidates will have to be ready for questions by undecided voters on a variety of topics.

Heading into the debate, a Reuters/Ipsos daily online tracking poll on Sunday (October 14) showed Obama leading Romney by 1 percentage point, 46 to 45, down from a 3-point Romney lead last Thursday - a possible sign that the Republican's surge after the first debate could be running out of steam.

But underlying trends in Reuters/Ipsos data are also worrying for Obama. They show voters are evaluating Romney more favorably on key issues that could influence how they vote, such as which candidate has the better plan to close the federal deficit and to move the economy forward.

The debate on Tuesday will be followed in less than a week by the final debate on foreign policy on October 22, giving the candidates one last chance to shift momentum in the election.