New Hampshire holds the first presidential primaries of 2008 today with polls predicting a huge victory for Barack Obama in the Democratic race and a remarkable comeback for John McCain on the Republican side.
Former Democratic frontrunner Hillary Clinton said that, regardless of what happens in New Hampshire, she will fight on until February 5th, when more than 20 states vote. John Edwards, who came second to Mr Obama in Iowa, said he would stay in the race until the Democratic national convention in August.
"We are so close. We've already changed the political landscape," Mr Obama told a rally in the south-western town of Lebanon yesterday. "We know that this can happen if we follow through, if we don't make this a flash in the pan."
With one poll giving Mr Obama a 13-point lead, Ms Clinton yesterday became emotional as she spoke to voters about the pressures of campaigning in a race she once looked almost certain to win.
"Some of us put ourselves out there and do this against some pretty difficult odds and we do it, each one of us, because we care about our country," she said, her voice trembling and her eyes welling with tears.
"But some of us are right and some of us are wrong. Some of us are ready and some of us are not."
Ms Clinton has sought to characterise Mr Obama as too inexperienced to be president, suggesting that he offers little more than inspiring rhetoric while she has a record of real achievement.
Her pitch appears to have failed to persuade New Hampshire voters, however, but her best hope of remaining a contender in the Democratic race may be to sow doubts about Mr Obama over the next three weeks.
Mr McCain, whose campaign seemed close to collapse last summer, is hoping to attract enough Independent voters to defeat former Massachusetts governor Mitt Romney, who has spent millions of dollars in New Hampshire. A defeat for Mr Romney today could doom his campaign, leaving Mr McCain to fight for the Republican nomination with former New York mayor Rudy Giuliani, former Arkansas governor Mike Huckabee and former Tennessee senator Fred Thompson.
Mr Huckabee, who won the Republican race in Iowa, has little hope of winning in New Hampshire and would be satisfied with a third-place finish ahead of Mr Giuliani.