SALEM, N.H. -- Sen. Hillary Rodham Clinton last night questioned Sen. Barack Obama's consistency on health care and his readiness for the presidency during the final Democratic debate before the New Hampshire primary.

The debate came just hours after a pair of new polls showed Mrs. Clinton, of New York, and Mr. Obama, of Illinois, in a virtual tie as Tuesday's vote approaches. It was a strong sign that Mrs. Clinton, once viewed by some as unstoppable, may have been hurt by her third-place finish in the Iowa caucuses last week.

"Making change is not about what you believe. It is not a speech you make. It is about working hard," Mrs. Clinton said in the debate at St. Anselm College. "I'm not just running on a promise of change. I'm running on 35 years of making change."

She faulted Mr. Obama for pushing a health care system that would leave millions of Americans without coverage, even though he expressed support for a "single-payer" national system several years ago.

"You stop short of going the distance to make sure that we have a system that can deliver health care for everyone," she said.

Mrs. Clinton's plan would mandate insurance for every American.

"I have been entirely consistent in my position on health care," Mr. Obama responded. He argued that his current proposal is the most practical because half of Americans rely on employer-based health insurance.

Former Sen. John Edwards of North Carolina criticized Mrs. Clinton's confrontation with Mr. Obama.

"I didn't hear these kinds of attacks from Sen. Clinton when she was ahead," he said.

Indeed, the contest in New Hampshire has narrowed.

A poll released last night by CNN and the New Hampshire television station WMUR showed that Mrs. Clinton and Mr. Obama were even at 33 percent support in the state, with Mr. Edwards well back at 20 percent. As recently as Wednesday, the day before the caucuses, Mrs. Clinton had held a slight lead in a poll conducted by the same organizations.

A Concord Monitor poll put out yesterday showed Mr. Obama with 34 percent of support among likely Democratic primary voters, while Mrs. Clinton had 33 percent.

In the CNN/WMUR poll, 60 percent of participants called Mr. Obama the most inspiring candidate. Only 18 percent picked Mrs. Clinton. But 46 percent of participants said she was the most experienced candidate, while just 14 percent put Mr. Obama in that category.

"He's very likable. I agree with that," Mrs. Clinton said when asked about the poll last night. "I don't think I'm that bad."

She and the other candidates all laughed, producing the first lighter moment in a tense debate.

On the campaign trail, the former first lady has been trying to emphasize her likability. During a morning appearance at Merrimack Valley High School in Penacook, several Hillary Rodham Clintons were on display: a compassionate Hillary, a comedic Hillary and a measured, thoughtful Hillary.

"Bill O'Reilly! Bill! How are you!?" she teasingly shouted to the conservative Fox News talk show host, one of her many long-time detractors, as he stood at the back of the gymnasium.

The Democratic crowd booed and hissed.

"You've got to give him points for courage," Mrs. Clinton said, prompting a round of laughter and applause.

With just three days to go before this state's primary -- and with election officials expecting a record turnout -- Mrs. Clinton is retooling her campaign message to show that she, too, would be a change agent, one who has the political and policy experience to push through a progressive agenda if she captures the White House.

"Who is ready to be president on Day One?" she asked voters. "The next president is going to face a lot of problems on that first day, Jan. 20, 2009. We have a war to end in Iraq. We've got a war to resolve in Afghanistan. We've got 47 million uninsured Americans. We have an economy that is faltering."

She added, sternly: "And we've got to take action now."

Mrs. Clinton also offered up some fiery, populist rhetoric, which was not a big part of her pre-Iowa stump speech.

"We're Democrats. People should stand for universal health care," she said in a booming voice. "And more independents and even Republicans are now understanding that it is morally and economically imperative that we finally in our country give universal health care to everyone."

Mrs. Clinton didn't mention Mr. Obama, her main competitor, until about 45 minutes into a question-and-answer session with voters, when she was asked to explain her support in the Senate for a non-binding resolution that designated Iran's Revolutionary Guard as a terrorist organization.

Mr. Obama and others have criticized the vote as a dangerous concession to a Bush administration that, at times, has appeared belligerent in its dealings with Iran.

Mrs. Clinton denied that, but insisted that the Iranian military force has smuggled weapons into Iraq, where they have been used to kill U.S. troops.

"We don't want, under any circumstances, for George Bush to take us to war with Iran. I have been against that," she said. "But I also think it's a mistake to ignore behavior that is directly causing the deaths of Americans. So, for me, this was an important statement."

At the start of the event, Mrs. Clinton spent almost 10 minutes helping her campaign organizers identify extra seats in the school gymnasium to make room for more supporters waiting outside. (A front-page story in the New York Times had noted that there were "empty seats" during a Clinton rally Friday at the University of New Hampshire.)

At one point, Mrs. Clinton herself walked over to a young woman with a baby and escorted them to a front-row seat.

"See, I'm a problem solver. I've been telling you that through this whole campaign," she said to laughter.

After her joking exchange with Mr. O'Reilly, she quickly became serious and turned her focus to the Iraq war, vowing to begin a phased withdrawal within two months of taking office. But she also emphasized the complications of pulling out troops and the need for patience.

Richard O'Brien, 60, said Mrs. Clinton's track record would trump Mr. Obama's message. And her Iowa performance wouldn't affect many New Hampshire voters.

"That's a lot of talking heads on TV and radio," he said. "Iowa is a couple of thousand miles away from here."

A pre-selected, diverse group of young people sat behind Mrs. Clinton as she spoke. Her daughter, Chelsea, stood at her side. It was a noticeable contrast with the older, recognizable faces from President Bill Clinton's administration who were on stage with her when she addressed the television cameras Thursday night after the Iowa caucuses.

Still, her husband is continuing to play a very central role on the campaign trail, despite criticism from some political observers who see him as a visible reminder that the Clinton family is part of the Washington establishment.

The former president can still bring out a huge crowd, and he is also promoting the campaign's message of experience and vision: "Ready for Change. Ready to Lead."

Yesterday, he was scheduled to appear at three events, while his wife, who was preparing for last night's debate, carried a lighter load.

"She's a change-maker, the best I ever saw," Mr. Clinton told a packed gymnasium at a high school in Amherst, where organizers had to turn hundreds of people away. He then detailed some of the highlights of her resume as a progressive leader: a stint as a young staff attorney for the Children's Defense Fund, author of a sweeping change in Arkansas' education law when Mr. Clinton was governor there, and her efforts at reforming the nation's health care system in the early 1990s.

Those efforts, he acknowledged, were a failure. But they also taught Mrs. Clinton how to rebound from defeat, Mr. Clinton said.

At moments, he seemed tired. And he clearly lacked the vigor of his 1992 New Hampshire primary campaign, when a second place finish earned him the title of "Comeback Kid." Yet, as he kept speaking, Mr. Clinton became more animated.

"Do want the feeling of change? Or do you want the fact of change?" he said, taking a shot at Mr. Obama's limited time in national politics.

Image, or "feeling," has undoubtedly played a role in the swift rise of the one-term senator. At events across the state, New Hampshire's younger voters often cite the 46-year-old Mr. Obama's freshness as a major attraction.

"He just seems more genuine," said Katie Partin, 18, a student at the University of New Hampshire who was waiting to get a glimpse of Mr. Clinton and plans to vote in her first primary election on Tuesday.

As Ms. Partin spoke, Lillian Fundeklian, 63, cut into the conversation: "Experience is No. 1. I'm a grandmother. I've worked since I was 5 years old. I know what it means to have experience."

Mr. Obama isn't there yet, she said. But Mrs. Clinton is.

It's a viewpoint that the New York senator hopes many New Hampshire voters will share when they head to the polls.