Democratic presidential hopeful John Kerry has won easy victories in the Nevada and Washington DC caucuses.
Kerry is getting his message out in Wisconsin
The Massachusetts senator has now won in 14 of the 16 states to vote so far, and is favoured to win Tuesday's crucial battle in Wisconsin.
Mr Kerry was the only candidate to campaign in Nevada, where he won easily over Howard Dean.
Now Democrats are focusing on Wisconsin, where candidates are to hold a debate on Sunday.
John Edwards, the only candidate still in the race who has defeated Mr Kerry, dismissed speculation that he might pull out if he does badly in Wisconsin.
"I'm completely committed to this race," he told supporters at a rally in Madison, WI.
Wesley Clark dropped out after last Tuesday's primaries, despite having won Oklahoma earlier in the campaign.
He has pledged his support to Mr Kerry.
In Washington DC, John Kerry won more than twice as many votes as his nearest rival, Al Sharpton, beating former Vermont Governor Howard Dean into third place.
"These results show that our campaign is uniting Americans from different parts of our country and walks of
life in a common purpose," said Mr Kerry, as the tallies came in.
Kerry - 63%
Dean - 17%
Edwards - 10%
Kucinich - 7%
Sharpton - 1%
Kerry - 47%
Sharpton - 20%
Dean - 17%
Edwards - 10%
Kucinich - 3%
He said he was already focusing his attention on President George W Bush and November's battle for the White House.
"I promise you that when the Republican
smear machine trots out the same old attacks in this
election, this is one Democrat who will fight back," he
With the Democratic nomination increasingly within his grasp, Mr Kerry could see his two main rivals - Senator Edwards and Mr Dean - leave the race if they do badly in Wisconsin.
Asked whether he expected to continue after Tuesday, Mr Dean would only say: "You will find out on Wednesday."
After Wisconsin on Tuesday, 10 states - including New York and California - will hold primaries on 2 March.
With opinion polls currently showing Mr Kerry running ahead of Mr Bush, the Bush re-election campaign on Thursday released a video accusing the Massachusetts senator of being "unprincipled".
The video was posted on Mr Bush's campaign website and a link sent to six million email addresses.
Dean is waiting until Wednesday
It counters Mr Kerry's oft-repeated claim that he would show special interests the door, by saying that "the only door he's shown special interests is the front door of his office".
Mr Kerry has put up his own advert on the internet, showing an empty Oval Office and a roll call of contributors to President Bush's campaign with the question: "Who has taken more special interest money than anyone?"
Most delegates who vote for a candidate at the national presidential nominating convention are allocated according to a candidate's support in state-wide caucuses or polls; some delegates are assigned for party leaders and elected officials to allocate.