HEMPSTEAD, New York (AP) — President Barack Obama went on the attack against Republican challenger Mitt Romney in a critical debate Tuesday, looking to rebound from an earlier matchup when he was seen as listless and distracted.

The stakes of the town hall-style debate could not have been higher. With just three weeks to go before Election Day, the race is locked in a dead heat and many Americans are already casting ballots in states with early voting.

Obama strode onto the stage seeking a stronger showing than in the initial debate on Oct. 3, when he had sent shudders through his supporters and helped fuel a rise in opinion polls by Romney, a former Massachusetts governor.

The open-stage format, with no physical objects between them, placed incumbent and challenger face to face and, when they chose, directly in each other’s faces. Their physical encounters crackled with energy and tension, and the crowd watched raptly as the two sparred while struggling to appear calm and affable before a national television audience.

From the opening moments, Obama was aggressive. He criticized Romney’s opposition to the Democrats’ bailout of the auto industry and rejected Romney’s economic proposals as squeezing the middle class.

theGrio: President Obama’s top moments from the second debate ↓

“Gov. Romney says he’s got a five-point plan. Gov. Romney doesn’t have a five-point plan. He has a one-point plan. And that plan is to make sure that folks at the top play by a different set of rules,”Obama said.

He also said Romney had shifted positions on energy, criticizing coal production years ago and supporting it now. At least twice, Obama accused Romney of being untruthful.

Romney responded in kind. He said the Obama administration’s spending was swelling the deficit and would lead to big tax hikes. He criticized Obama’s handling of the economy and blamed the president for high gasoline prices.

“The middle class has been crushed over the last four years,” Romney said.

The two men interrupted one another early and often, speaking over each other to the point that neither could be understood.

“You’ll get your chance in a moment. I’m still speaking,” Romney said as he tried to cut off Obama at one point.

There would be little time for either candidate to recover from a weak showing Tuesday. Only one more debate, next Monday, remains after Tuesday’s faceoff and that one deals with foreign policy, a secondary issue in a race dominated by the economy.

Tuesday’s debate was before an audience of 80 uncommitted voters posing questions to the candidates. Obama needed to strike the right balance in coming on strong against Romney without turning off the audience — and tens of millions of television viewers — by going too negative.Obama has said his first debate performance was “too polite.”

The economy, the biggest issue in the election, was unsurprisingly the first topic in the debate. There are sharp differences between the two candidates. Obama says his policies prevented a catastrophic economic meltdown, saved the U.S. auto industry and has put the economy on the road to recovery. Romney, a wealthy businessman, argues that Obama has failed to turn around the economy and it is time for new leadership.

Romney says he would revamp taxes, cut wasteful spending and crack down on what he sees as unfair trade practices by China. Obama says Romney’s proposals are vague and would favor the wealthy over the poor and middle class.

International issues were also part of the debate, the first time the candidates have squared off on the subject. Obama has long held an advantage in polls as the better candidate for handling foreign affairs. His campaign points to his withdrawal of U.S. troops from Iraq and the killing of terrorist leader Osama bin Laden. But Romney’s campaign has put Obama on the defensive over his handling of security at the U.S. Consulate in Benghazi, Libya, where four Americans, including the U.S. ambassador, were killed last month.

Romney pressed the White House on the matter last week after Joe Biden said in the vice presidential debate that “we weren’t told” about requests for extra security at the consulate. But State Department officials, testifying before Congress that day, said they were aware of those requests. Secretary of State Hillary Clinton backed up the White House’s assertion that the issue didn’t rise to the president or vice president’s attention.

Asked by an audience member about the attacks, Obama said he was ultimately responsible for the security of diplomats and was committed to investigating what went wrong. Romney criticizedObama for attending political events in the aftermath of the attacks. He said the attacks call into question all of Obama’s Middle East policies.

The Republicans’ attention to foreign affairs marks something of a shift. They had long sought to make this election a referendum on Obama’s handling of the economy. But that may now be a tougher sell. Unemployment, which had been over 8 percent, for much of Obama’s term, fell to 7.8 percent last month. The housing market is improving and consumer confidence is rising.

Obama is fighting to hang on to small leads in many of the nine key swing states that likely will decide the election. The so-called battleground states — those that do not reliably vote either Republican or Democratic — take on outsized importance in the U.S. system, in which presidents are chosen not by the nationwide popular vote but in state-by-state contests.

Tuesday’s debate audience of uncommitted voters was selected by the Gallup Organization. Moderator Candy Crowley of CNN chose speakers after reviewing proposed questions to avoid repeats.