The Democratic field, thrown wide open by Mrs Hillary Clinton's surprise win in Tuesday's New Hampshire primary, thinned out with the withdrawal of New Mexico Governor Bill Richardson.

Leading Republicans sparred in Michigan, a heavyweight state scarred by industrial decline, before descending on South Carolina for an evening debate.

Mrs Clinton's vanquished opponent on Tuesday, Mr Barack Obama, won the backing of the Democrats' 2004 standard-bearer, Mr John Kerry, as Mr Obama wowed supporters in sunny South Carolina with his call that 'our time for change has come.'

The Massachusetts senator, who lost the 2004 election to President George W Bush, said he 'dared to hope' then that the healing of a fractured country might begin.

It had not, Mr Kerry said in a fiery speech in Charleston, South Carolina.

'But I believe that more than anyone else Barack Obama can help our country turn the page and get America moving by uniting and ending the division that we have faced,' he said.

Swatting aside Mrs Clinton's charge that Mr Obama is offering 'false hopes' to voters, Mr Kerry said: 'My friends, the only charge that rings false is one that tells you not to hope for a better tomorrow.'

The Obama campaign will be hoping Mr Kerry's endorsement might influence other Democratic power-players who have so far stayed neutral in the nail-biting nomination race.

Mr Kerry's vice presidential running mate in 2004, Mr John Edwards, is back in the race this year, and is campaigning hard in his native South Carolina after disappointing finishes in Iowa and New Hampshire.

In a statement, Mr Edwards said he respected Mr Kerry's decision to support his rival in the 2008 contest.

'Election about the future, not the past'
But he added that this election was 'about the future, not the past,' promising to take on the status quo on behalf of the powerless.

In Mr Edwards' narrative, the former first lady is part of a discredited old guard that must be swept aside to move the United States on from two decades of Bush and Clinton presidencies.

But the New York senator was in fighting mood, after her come-from-behind triumph in New Hampshire short-circuited Mr Obama's post-Iowa surge and set up a truly nationwide contest.

Mrs Clinton exposes her inner self
Acknowledging that she had faced a 'big problem,' the steely Mrs Clinton said she had exposed her hidden inner self when she nearly wept during a campaign stop on Monday.

'And I just determined that I was going to dig down deep and reach out and listen and talk,' she told CBS News in an interview aired late on Wednesday.

'And do what I have always done, which is what makes me get up in the morning, and that is to figure out how I could tell people what I want to do to serve them.' Gov Richardson, a Hispanic former UN ambassador, called time on his campaign after his fourth-placed finishes in Iowa and New Hampshire.

'I gave this race the best I had,' he said, quitting ahead of the Jan 19 caucuses in Nevada, where polls suggest he is well behind despite the state's large Hispanic community.

Gov Richardson said he would stay on the fence as the Democratic survivors fight it out, but called for a civil contest.

Call for no personal attacks
'And all I ask of the candidates is that they do not resort to personal attacks to win the nomination. Our country and our party deserve better than that.' Mrs Clinton campaigned in Nevada while Mr Obama joined a clutch of other candidates in the stew of race, religion and cut-throat machinations that characterizes politics in South Carolina.

New Hampshire winner Mr John McCain and former Massachusetts governor Mitt Romney duelled at competing rallies in Michigan ahead of its Republican primary on Jan 15, before heading south for the televised debate.

Mr Romney has yanked all his TV advertising from South Carolina and Florida to focus his fire on Michigan, where he was born, after his lavishly funded campaign tripped up at the first two hurdles.

The Republican winner in Iowa, former Arkansas governor and Baptist preacher Mr Mike Huckabee, wooed South Carolina's evangelical conservatives before heading Friday to Michigan, where his economic populism is resonating.

Further south, former New York mayor Rudolph Giuliani remained camped out in Florida as he lay in wait for 'Super Tuesday' on Feb 5, when primaries will be held in more than 20 states, including California and New York. -- AFP