DENVER - From the first question, Mitt Romney was on the attack.
So was Barack Obama.
But during their 90-minute encounter, the first of three presidential debates, the Democratic president sometimes seemed annoyed and defensive while his Republican challenger was energetic, focused and relentlessly on message. Romney ripped Obama's record on the economy with a tone calculated to convey more sorrow than anger.
He told the stories of individuals who have come up to him and his wife, Ann, at campaign events asking for help in getting a job or saving their home from foreclosure. "Yes, we can help," he said, looking straight into the camera, speaking to the millions of voters watching from their homes, not the hundreds in the University of Denver arena. "But it's going to take a different path, not the one we've been on."
Obama hammered Romney for tax proposals he said didn't add up and economic policies he said would benefit the wealthy and damage the middle class. He defended the Affordable Care Act for its most popular provisions, including protecting those with pre-existing medical conditions. But he never raised that secretly recorded video in which Romney described 47% of Americans as "victims" who are dependent on the government and he never pressed Romney on his record as head of Bain Capital - both issues his campaign has pushed.
When it was over, it was clear which side was more eager to talk about the debate. Republican surrogates immediately flooded the media center. The Democratic ones didn't follow until several minutes later, and they left while the other side stayed to spin.
In a serious, rapid-fire discussion, the two men laid out fundamentally different visions for the role of government and the best way to lead the nation to prosperity.
"Free market and free enterprise are more effective in bringing down costs than anything," Romney said in the discussion of health care. "The private market and individual responsibility always works best."
Obama talked about the responsibilities of citizens to one another and described spending on education and other programs as an investment that in the end spurs growth and jobs. "The federal government can't do it all, but it can make a difference," he said in an exchange in which he extolled Abraham Lincoln.
There wasn't an embarrassing gaffe or a single sharp exchange that defined the evening, as there sometimes is with presidential debates.
Romney again and again reminded voters of their economic woes and blamed Obama's policies for contribution to slow job growth, increasing poverty, home foreclosures. He questioned Obama's economic competence. "Going forward with the status quo is not going to cut it for the American people who are struggling today," Romney charged as Obama frowned.
And Obama again and again raised questions about whether Romney's numbers added up and if his policies would work, saying his tax proposals would explode the deficit and benefit the wealthy. When Romney disputed that, saying he wouldn't reduce the tax burden on the wealthy or approve tax cuts that increased the deficit, the president expressed incredulity.
"Now four weeks before the election, he is saying his big, bold plan is: Never mind," Obama said. He accused Romney of proposing to "double down" on economic policies that contributed to the economic meltdown that greeted him four years ago in the Oval Office.
In other words, Romney cast the election as a referendum on Obama's first term in office. Obama cast it as a choice between his plans and those of his opponent.
Much of the discussion was a festival for fact-checkers, a dizzying competition of numbers on tax policy, on the costs of the proposals each has made, on Romney's record as governor of Massachusetts and Obama's tenure as president.
Both men talked fast, tried to hold the floor and often ignored the entreaties of moderator Jim Lehrer to respond to his specific questions or to move on to the next topic. At times, they interrupted and talked over one another.
But Romney showed the value of the 19 debates he participated in during the GOP primaries and the extended practice sessions he has scheduled in recent weeks. He seemed relaxed and conversational, repeatedly referred to individuals he had met on the campaign trail, and gave no quarter when challenged by the president.
Obama, in contrast, hadn't debated since the last of his three encounters with John McCain four years ago. Not since then has he faced an opponent on a level playing field - the podium in front of him not even adorned with the presidential seal. He understandably didn't seem to relish having his record challenged in a direct way presidents rarely face.
After Obama vowed to reduce the federal budget deficit in his second term, Romney told him, "You've been president four years."
Bill Galston, an adviser to President Clinton and other Democrats and who is now at the Brookings Institution, said Romney "did himself considerable good" in the debate. "I would not be surprised to learn that a majority of the American people think he won it outright," Galston said in an e-mail. "I suspect that over the next week, the public opinion surveys will show a significant narrowing of the gap between President Obama and his re-energized challenger."
"He crushed it," Sen. John Thune, R-S.D., said of Romney. "Most people came away seeing a Mitt Romney they hadn't seen before."
Romney had never participated in a debate in which the audience was so large and the stakes so high.
Since the Democratic National Convention last month, polls show Obama has opened a narrow lead nationwide and a bigger one in such swing states as Ohio and New Hampshire. If Obama could be satisfied with a draw, Romney went into the race needing to shake things up.
The debate offered a more substantive discussion of the two candidates' proposals than much of the campaign to date. Even though the two sides effectively have been campaigning against one another for most of the year, the vast majority of ads have been negative and the points of attack often an ill-considered comment by the other guy.
Wednesday night, they explored the considerable differences between them on how they would spur growth and their views on the role of government in the 21st century. The length of the debate, a less rigid format than in previous elections and the focus on four broad topics were designed to encourage a substantive discussion.
The ideological divide between Obama and Romney on dominant questions of the day - this year, it's the economy and its slow climb out of recession - is as wide as it has been in any presidential election in more than a generation.
On that, at least, the two contenders seemed to agree.
"Four years ago, we were going through a major crisis," Obama said in his closing statement. "The question now is: How do we build on those strengths?"
Romney, who courtesy of a coin toss got the last word, said a second Obama term would lead to deeper economic travails. The two candidates offer "two very different paths," he said. "They lead in very different directions."