-- PHOTO: AFP

But the outcome of Saturday's nominating contests also means Mr John McCain will need to exert himself to justify his presumptive Republican Party nominee status.

Mr Obama had his best night yet, sweeping four contests and closing the narrow gap with Mrs Hillary Clinton.

In the Republican camp, an irrepressible Mike Huckabee defied his party's front runner McCain in two states and yielded a narrow win in the third.

Mr Obama, 46, won roughly two-thirds of the vote in the caucuses held in Washington state and Nebraska on Saturday. He took nearly 90 per cent of the vote in the US Virgin Islands.

In Louisiana, Mr Obama won 57 per cent of the vote to Mrs Clinton's 36 per cent.

'We won north, we won south, we won in between,' Mr Obama said at a Democratic Party dinner in Richmond, Virginia, on Saturday where he was campaigning for upcoming contests.

Mrs Clinton, 60, who spoke at the same function earlier, did not mention Mr Obama's success.

'It's not about who's up or who's down,' the New York senator said as she made the case for her bid to become the first woman president of the United States.

'It's about your lives, your families, your futures and isn't it time you had a president who brought your voice and your values to the White House?'

Expecting that Washington DC, Maryland and Viriginia will favour Mr Obama in contests tomorrow, the Clinton campaign is portraying her as the better candidate to fight Republican front runner McCain while looking ahead to March when bigger states such as Texas and Ohio will weigh in.

Mr Obama, who is closing in on Mrs Clinton's slim lead in the race for the 2,025 delegates needed to be the nominee, stressed his supposed merit as a Washington outsider to take on Mr McCain.

'We owe the American people a real choice,' said the man trying to become the first black president of the US.

'It's a choice between debating John McCain about who has the most experience in Washington or debating him about who's most likely to change Washington.'

In all, the Democrats were in the game for 161 delegates in Saturday's contests. In incomplete allocations, Mr Obama won 72 and Mrs Clinton 40.

Yesterday, Mr Obama and Mrs Clinton were facing off in caucuses in Maine, where 24 delegates are at stake.

For the Republicans, the fight to be the party's nominee has all but been clinched by Mr McCain, 71. But he has yet to win the hearts of conservatives. A straw poll at the Conservative Political Action Conference on Saturday showed the choice of core Republicans is the man who has pulled out of the race - former Massachusetts governor Mitt Romney.

Add to that Mr Huckabee's decisive wins in Kansas and Louisiana and his strong showing in Washington, and Mr McCain's weak spot is visibly troublesome.

Mr Huckabee had nearly 60 per cent of the caucus vote in Kansas, winning all 36 delegates. He also won the Louisiana primary, with 44 per cent to 42 per cent for Mr McCain. Still, that was short of the 50 per cent needed to take the 20 delegates available. These will be awarded at a state convention next weekend.

Mr McCain won the Washington state caucuses by 26 per cent against 24 per cent for Mr Huckabee and 21 per cent for Texas congressman Ron Paul. The state's delegates will be awarded next week.

Mr Huckabee, 52, has vowed to stay on in the race until Mr McCain manages to clinch the 1,191 delegates he needs to be crowned the party nominee.

He remains far behind Mr McCain in the delegates tally, with no mathematical possibility of catching up. But the Baptist preacher plays by his own logic. 'I didn't major in maths. I majored in miracles, and I still believe in them,' he said.

'There are only a few states that have voted - 27 have not. People in those 27 states deserve more than a coronation, they deserve an election.'

He stepped away from suggestions that he was running to be Mr McCain's vice-presidential pick.

'I don't have any illusion that Senator McCain would select me as a running mate, or that I would automatically select him,' Mr Huckabee said.

bhagya@sph.com.sg