The war in Iraq, as expected, generated most of the heat, with Hillary’s slow and nuanced retreat from her ’02 Senate vote to authorize the war clashing vividly with the blunt penance-seeking pleadings of one her main rivals, John Edwards.

That dynamic is hardly new to the Democratic race – although Mr. Edwards was far more forceful in playing it up than he was in the first debate – but it threatens Mrs. Clinton far more in activist-dominated Iowa than in New Hampshire, where next year’s primary will draw nearly as many independents as registered Democrats.

And so it was that Mrs. Clinton offered a confident, assertive, and even – at times – defiant and humorous presentation tonight that sought to turn her vulnerabilities with her party’s base into strengths with New Hampshire’s moderate and independent-minded electorate.

For instance, after Mr. Edwards repeated his assertion that the “war on terror” is a cynical Bush administration construct and rejected suggestions that domestic security has improved since 9/11 – a pitch-perfect Valentine to the left – Mrs. Clinton invoked her ties to New York and said: “I believe we are safer than we were, but we are not yet safe enough.

Shortly thereafter – and after some mischievous prodding from CNN’s Wolf Blitzer, who moderated the festivities – Mr. Edwards called Mrs. Clinton and Mr. Obama out by name, accusing them of trying to have it both ways. In casting “no” votes on the supplemental war funds bill signed by Mr. Bush last month, Mr. Edwards strongly suggested, they were merely paying lip service to the left – since both announced their opposition at the last minute and kept the volume of their protests to a minimum.

“All of us have a responsibility to lead on this issue,” Mr. Edwards intoned, playing to one of the anti-war crowd’s strongest objection to Mrs. Clinton.

Given the chance to respond, Mrs. Clinton downplayed the differences of opinion the Democratic side, stressing the unity within the party on how disastrous the war has been and the idea that it needs to be ended.

“The differences among us are minor,” she said as she pegged the blame to President Bush, and not the the Democratic Congress of which she is a member. “The differences between us and the Republicans are major.”

(Mr. Obama, who voiced opposition to the war as an Illinois state senator in 2002, engaged Mr. Edwards directly, addressing the North Carolinian by his first name and reminding him: “you were about four-and-a-half years late on leadership on this issue" – a response that undoubtedly played better with the party base than Mrs. Clinton’s.)

Mrs. Clinton was also grilled – as she was in the first debate – on the rationale for her ’02 Senate vote. Specifically, she was asked whether she regrets not reading a National Intelligence Estimate that, many on the left contend, could have changed the outcome of the war resolution debate had its findings been more widely circulated. She said she didn’t, and then employed her increasingly familiar tactic of blurring her differences with her opponents, arguing that she hadn’t actually voted for the war, but rather to simply give Mr. Bush the authorization to do so only after an exhaustive round of weapons inspections in Iraq.

That is not an answer that will reverse her Iowa numbers. But, again, it was an answer that will play better in New Hampshire, the only state to flip its allegiances to the Democrats between the 2000 and 2004 presidential elections.

Under New Hampshire’s rules, independent voters can opt to participate in either party’s primary. They flocked to the Republicans in 2000, for instance, fueling John McCain’s rout of Mr. Bush – and denying Bill Bradley an upset with over Al Gore on the Democratic side. But the state’s ideological shift – long the last bastion of conservatism in the Northeast, New Hampshire voters threw out both of their Republican congressmen last year and also installed a Democratic legislature for the first time since the Civil War – along with the low standing of the national G.O.P. should mean that independents will favor the Democratic race in ’08.

Those independent voters probably aren’t particularly alarmed by Mrs. Clinton’s lack of stridency on Iraq, just as they are probably comforted by the general competence and policy command she showed throughout the rest of the debate.

Indeed, late in the debate, Mrs. Clinton led a rebellion among the candidates against Mr. Blitzer’s incessant use of the raise-your-hand-if-you-would-do-this school of questioning. Instead of playing along when he asked who would favor military action in Darfur, Mrs. Clinton reminded him that “one of the jobs of being President is to be very rational in approaching these kinds of situations, and I don’t think it’s helpful to be talking about these kinds of hypotheticals.” The audience broke into applause. It was, it seemed, a presidential moment – especially to an independent voter.

Contrast that with Mr. Edwards and his black-and-white rhetoric on Iraq, health care and other issues near and dear to the left. To a national Democratic Party whose anti-war base feels betrayed by their own Congressional leaders on Iraq, Mr. Edwards’ critiques of Mrs. Clinton – and even Mr. Obama – resonated. But that base holds more sway in Iowa – where Mr. Edward has led in polls for a year now – than in New Hampshire, where Mrs. Clinton scored 34 percent in the latest survey, well ahead of Mr. Edwards (15 percent) and Mr. Obama (18 percent).

Mrs. Clinton did tend to the base on other issues, endorsing the demise of her husband’s “don’t ask, don’t tell” policy and the inclusion of openly gay people in the military (invoking a the words of a Republican, Barry Goldwater, in doing so) and affirming her support for universal health care. And, notably, she produced the night’s best laugh line. Observing that the Bush administration’s ideas of diplomacy is limited to sending Condoleezza Rice on periodic trips around the world, she said: “Occasionally, they even send Dick Cheney – and that’s hardly diplomatic, in my view.”

While Mrs. Clinton and Mr. Edwards provided the most memorable moments of the night, Mr. Obama held his own. Not only did he knock Mr. Edwards for his ’02 war vote, he also went toe-to-toe with him on health care. In the longest back-and-forth of the evening, the two quibbled about the merits of their plans, with Mr. Edwards criticizing Mr. Obama’s for not mandating coverage for everyone.

Mr. Obama stood his ground, though, and had the last laugh – pointing out that his plan does mandate coverage for children after Mr. Edwards claimed it didn’t. The wonkish exchange was invaluable to Mr. Obama, given the skepticism he has faced over his lack of experience in national politics and policy-making.

But it was Mr. Edwards who tried to make his move tonight, and it was Mrs. Clinton who was most vulnerable to his gambit. They both had reason to walk away satisfied.