More from Gerard Baker on our US elections blog

The leading candidates for the Democratic nomination exchanged their sharpest blows yet in last night’s presidential debate but Senator Hillary Clinton emerged in better shape than she did after the last debate two weeks ago.

Appropriately in Las Vegas, which has hosted some of the most famous boxing bouts in history, the evening began with a fierce head-to-head tussle between Senator Clinton and Senator Barack Obama, in which the two leading candidates jabbed pointedly at each other’s policies and record.

But after the initial skirmishes Mrs Clinton seemed more at ease than she had in the last debate, which began by far her worst period in the election campaign so far. In fact, in an odd reversal of fortune, it was Mr Obama who slipped badly on the very issue that tripped up Mrs Clinton in Philadelphia. Asked by CNN’s Wolf Blitzer, the moderator, whether he supported giving drivers’ licences to illegal immigrants, he prevaricated repeatedly, and only at the fourth asking did he answer “Yes”. In Philadelphia, Mrs Clinton’s failure to give a straight answer to the same question was seized on by her opponents as evidence that she could not be trusted because she tends to “straddle” issues that are politically controversial. But last night Mr Obama opened himself up to the very same criticism.

The debate was often rowdy, with repeated interventions, cheers and even catcalls from the invited crowd at the University of Nevada, Las Vegas. John Edwards, the former North Carolina senator who is running third in the polls behind Mrs Clinton and Sen Obama, again offered the sharpest critiques of Mrs Clinton, but his repeated attacks seemed not to go down well with the audience, while the former First Lady and Sen Obama were loudly applauded throughout.

The other, minor candidates once again tried to break through into the top tier, but without obvious success.

The disagreements at the top of the debate centred on Mrs Clinton’s claims that her proposals on health insurance were more generous than Mr Obama’s.

Mr Obama told her, “what the American people are looking for right now is straight answers to tough questions and that is not what we have seen out of Senator Clinton in the last month.”

Mrs Clinton, with barely disguised disdain, said Mr Obama, “talks a lot about stepping up and taking responsibility and taking strong positions. But when it came time to step up and decide whether or not he would support universal health care coverage he chose not to do that.”

Mrs Clinton’s stronger performance last night seems likely to stabilise her campaign somewhat after a rocky two weeks. Following her equivocal performance in the previous debate, Mrs Clinton seemed to suggest she was being picked on by her male opponents because she was a woman. Her husband, former president Bill Clinton then weighed in with a bizarre attack on her critics for what he claimed was an attempt to unfairly defame her. When it was revealed that she had planted a question among her audience at a campaign event last week, she seemed to lose more altitude.

But as her campaign team point out, none of this has been reflected in any significant way in the opinion polls, in which she still enjoys a large lead.

Her biggest challenge remains in the first primary contest in Iowa, on January 3, where she seems to be running neck and neck with both Mr Obama and Mr Edwards. A failure to win the caucuses there will cast real doubt on her electability heading into the crucial New Hampshire primary which is expected to take place just five days later.

Last night, for the time being at least, she will have calmed the slightly frayed nerves of her large army of supporters.

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