DENVER — Mitt Romney, needing a strong showing in the first presidential debate Wednesday night, delivered a commanding one, helped by a flat rival who was forced to defend the past.
Over 90 minutes, before tens of millions of TV viewers, the Republican nominee clashed with President Barack Obama on taxes, the future of Medicare and how to create jobs. He portrayed Obama as a failure, unable to lead the country out of a still-struggling economy.
"We know that the path we're taking is not working," Romney said. "It's time for a new path."
Obama was defending himself the moment he walked on stage.
"Four years ago we went through the worst financial crisis since the Great Depression," he said, trying to lay the predicate of his re-election effort that his policies, including the auto bailout, averted greater disaster.
"We all know that we've still got a lot of work to do," Obama said. "And so the question here tonight is not where we've been, but where we're going."
But Obama never gained momentum in making that case, both appearing and sounding subdued. His weaknesses were also reflected by what he did not say — squandering an opportunity to knock Romney on comments he made about "47 percent" of the public being dependent on government.
Romney, by contrast, was confident, prepared and aggressive. He often brushed aside moderator Jim Lehrer's attempts to move on to another topic.
Romney peppered Obama with figures and drew clear differences, saying he would not raise taxes to cut the deficit, would repeal the health care law and back a plan that would allow seniors to enter a privatized version of Medicare, if they choose.
The Republican provided broad outlines of a plan that includes increasing trade, boosting energy output and improving education.
When Obama said he had presented a plan to Congress to cut the deficit by $4 trillion, Romney scoffed, "But you've been president four years."
Obama returned fire over the new health care law, noting that the plan Romney enacted as governor of Massachusetts was "essentially the identical model" of what the president now embraces as "Obamacare."
"The fact of the matter is, we used the same advisers, and they say it's the same plan," Obama said to his rival. He accused Romney of not offering concrete alternatives to health care, financial reform and other issues.
Wednesday's showdown came at a pivotal moment in the campaign. National and swing state polls, including Florida, Ohio and Colorado show Obama with a slight or better lead, and Republicans have grown concerned about the trajectory.
Romney has time — and an economy marred by an 8.1 percent national unemployment rate — but needed a strong night to propel the campaign into the final four weeks, during which the men will engage in two more debates, including Oct. 22 at Lynn University in Boca Raton.
By then, millions of Americans will have already voted and most others have long decided on their candidate.
Obama and Romney were competing Wednesday for the small slice of undecided voters — and the open question is how many of them Romney might have convinced, particularly in a debate that lacked memorable moments.
Romney seemed keenly aware of the stakes and drew on his experience from a string of contentious debates in the Republican primaries. To get in his points, Romney was not afraid to talk over moderator Lehrer.
"I love Big Bird," Romney said at one point, after saying he would cut funding for the Public Broadcasting Service.
The debate was designed to be freewheeling, with a slate of 15-minute segments, though Lehrer struggled to keep it moving.
"Excuse me. Excuse me. Just so everybody understands, we're way over our first 15 minutes," he said early on.
The second debate, in New York, will be town hall style with questions from the audience on foreign and domestic issues. Candidates will be limited to a two-minute response, though moderator Candy Crowley can extend that.
The early focus Wednesday was on Romney's plan to reduce income tax rates for everyone by 20 percent.
Obama said it was impossible to carry out without raising taxes on the middle class or "blowing up" the deficit — points taken from an independent study that cast doubt on Romney's proposal.
The Tax Policy Center said that even if Romney eliminated all deductions for the rich, his plan would not generate enough revenue to pay for lower tax rates — and concluded that the only way to make that up would be to reduce or eliminate tax breaks for middle-income taxpayers, who would then see a net increase in their tax payments.
Romney's campaign has disputed the study.
"Virtually everything he just said about my tax plan is inaccurate," Romney said. "I'm not looking for a $5 trillion tax cut. What I've said is I won't put in place a tax cut that adds to the deficit."
He adamantly vowed, "I will not under any circumstances raise taxes on middle-income families. I will lower taxes on middle-income families."
Obama mocked Romney for lack of details and said it was not possible to eliminate enough deductions without raising taxes or increasing the deficit.
"It's math; it's arithmetic," the president said, channeling what former President Bill Clinton said during the Democratic National Convention last month in Charlotte.
But Romney said Obama had failed on his promise to cut the deficit by half. Obama has countered that the poor economy made that impossible and pressed a "balanced" approach that includes budget cuts but also more tax revenue.
"You know, when Gov. Romney stood on a stage with other Republican candidates for the nomination and he was asked, would you take $10 of spending cuts for just $1 of revenue? And he said 'No,' " Obama said. "Now, if you take such an unbalanced approach, then that means you are going to be gutting our investments in schools and education."
Romney countered, "Look, the revenue I get is by more people working, getting higher pay, paying more taxes. That's how we get growth and how we balance the budget. But the idea of taxing people more, putting more people out of work, you'll never get there. You'll never balance the budget by raising taxes."
On jobs, Obama said he wanted to hire another 100,000 math and science teachers and create 2 million more slots in community colleges so people can get training for better work.
Romney said he wanted to focus on education, too, but tried to draw differences over energy policy, saying he supported a proposed oil pipeline from Canada and supporting coal: "And, by the way, I like coal. I'm going to make sure we can continue to burn clean coal. People in the coal industry feel like it's getting crushed by your policies."
Inside a gymnasium at the University of Denver that had been converted into a workspace for 3,000 journalists, partisan operatives flooded into the "spin zone" to amplify campaign messages and assign winners and losers.
With 33 days until Election Day, former New York Mayor Rudy Giuliani made it seem like there was an eternity to go.
"The Romney campaign," Giuliani told reporters, "is really just getting started."
Alex Leary can be reached at email@example.com. Follow him on Twitter @learyreports.