It may prove to be too late for Hillary Clinton - particularly if anything can be read from the swelling New Hampshire crowds Barack Obama is attracting. But no one could accuse her of overlooking the message sent by Iowa's voters last week who placed her third behind Mr Obama and John Edwards.

Canvassing among the very different and much smaller New England electorate of New Hampshire on Sunday, Mrs Clinton repeated one word over and over again: "change". Speaking with voters in the small town of Nashua, the erstwhile Democratic frontrunner said the choice posed between "change" and "experience" was a false one.

The former First Lady offered a curriculum vitae based on "35 years of change" against her rival's "fine-sounding" and high-minded "promise of change". At a high school event in Penacook on Saturday, Mrs Clinton even compared a vote for Mr Obama - now widely described as the "agent of change" in an election that pundits say will be defined by who best captures that mantle - with a vote for George W. Bush.

"It is hard to remember how in 2000 he [Mr Bush] said he would be a uniter and not a divider," said Mrs Clinton. "He was going to bring America together. He was going to end partisanship. He didn't need a lot of experience because he had good intuition. He understood people and he'd be able to meet these rogue leaders, look them in the eye, read their souls and solve our problems. Remember that?"

Yet in Sunday's frantic rush of candidates from one snow-laden small town to another, there was little mistaking which candidate was attracting the buzz. It took more than an hour for vehicles to exit a crammed New Hampshire Obama rally that had to book an overfill hall after almost 3,000 people turned up.

The same contrast in tone was apparent in Saturday night's presidential debate at Anselm College, when a visibly tense - and at times indignant - Mrs Clinton faced an almost beatifically confident Mr Obama. Their body language, which left no room for doubt who was now the frontrunner, was the reverse of that displayed in the previous 13 Democratic television debates over the past 10 months.

Having for the most part ignored her rivals in previous encounters - as part of the "inevitability" strategy that she has now hastily abandoned - this time Mrs Clinton attacked Mr Obama directly and repeatedly.

She attacked his healthcare plan for lacking an "individual mandate" that would compel all adults to take out insurance, unlike both her own and Mr Edwards' plan for universal coverage. And she pointed out that the head of Mr Obama's New Hampshire campaign had lobbied for the pharmaceutical industry.

Mr Edwards, who now associates himself with Mr Obama against Mrs Clinton as a candidate of change against the "forces of the status quo", attacked her for taking money from lobbyists. Mrs Clinton's riposte was on Sunday replayed over and over on television. "I want to make change but I've already made change," she said. "I will continue to make change. I'm not just running on a promise of change. I'm running on 35 years of change."

Opinion polls suggest that Mr Obama's victory in Tuesday's primary vote in New Hampshire is by no means assured. Of two polls on Sunday, one gave Mr Obama a two-point lead and the other put him and Mrs Clinton in a dead heat with 33 per cent each and 20 per cent for Mr Edwards.

Nor, in a state that never lets outsiders forget its motto of "Live Free or Die", can it be assumed that New Hampshire's independent-minded voters will meekly replicate what Iowa's caucus-goers decided last week. The two states often produce different winners and New Hampshire has a better record of choosing the eventual nominee.

But the wind is blowing Mr Obama's way. Sitting in the popular Mary-Anne's diner in Derry on Sundaymorning, Jonathan Anderson, a 38-year-old Democrat, echoed the reasoning of many below the age of 40 in explaining how he would vote tomorrow.

He said he made up his mind last week when he concluded Mr Obama was more "authentic" - a factor he said would even help the US in its fight against terrorism.

"The best we could do is put someone in the White House who is perceived as different," he said. "Open the history books - they all look alike. You don't see a black guy, but maybe you should."

By Edward Luce and Stephanie Kirchgaessner, Financial Times, January 6, 2008