After five months of hard-fought, costly primary elections, the final duel between Barack Obama and Hillary Clinton begins later Saturday at a tense Democratic Party meeting about rules, followed by three more primaries in the following days, reported the dpa.
After primaries in Puerto Rico on Sunday and Montana and South Dakota on Tuesday, Democratic congressional leaders have called for the remaining undecided special delegates to take a stand.
But even with strong wins at all four events, Senator Clinton's chances of winning the party's nomination are slim. Senator Obama, 46, has 1,984 elected delegates to 1,782 for Clinton, 60, and proportions are unlikely to change much.
Nonetheless, Clinton put a strong face on it Friday, smiling and shaking hands on the campaign trail.
"What I'm hoping is that delegates, including the so-called super- delegates, will ask themselves who they think is the better president to be our commander in chief and to turn the economy around, and who would be the stronger candidate" against the presumptive Republican candidate, Senator John McCain, Clinton said in Montana.
At Saturday's party meeting, the 30-member rules committee of the Democratic National Committee will hear challenges from Michigan and Florida's Democratic parties to seat their delegates.
The two states violated the party's schedule for primaries, running the risk of losing their seats at the convention in August in Denver. Clinton and Obama obeyed instructions not to campaign there, but put both of their names on the Florida ballot.
Clinton, whose name also appeared on the Michigan ballot, wants the votes to be honoured, since she came out strongly ahead of Obama, arguing that shutting out the two populous, key states could alienate Democratic voters in the November 4 general elections.
"You can't afford to disenfranchise (the) millions who turned out," said Lanny Davis, a power in the Democratic Party, in broadcast remarks. "If they're not seated, you can kiss both of them goodbye."
Of the committee's 30 members, 13 are declared for Clinton and eight for Obama. The other nine are undeclared.
Clinton's supporters plan to march through Washington on Saturday to the hotel where the meeting is to be held.
Susan Turnball, vice chair of the DNC, said Friday that she expected a "great compromise" would be made that would make sure people "feel as if it's been a fair and equitable process."
"What we all also want to do is make sure we honour and respect the voters on Michigan and Florida," she said in broadcast remarks.
In addition to elected delegates, nearly 800 super delegates - elected and party officials - have a say in the nomination. Most have declared their support, but 160 have not done so.
Earlier this week, Speaker of the House of Representatives Nancy Pelosi and the Senate majority leader Harry Reid called for them to take a stand soon after Tuesday's final votes.
"I think super-delegates ... do realize what we want to do is have a united party, have a candidate moving forward as quickly as possible," Turnball said.
In her arguments, Clinton has often evoked the 2000 Florida debacle that is still raw in many Democrats minds. George W Bush claimed the state - and therefore the presidency - over Al Gore by a mere 537 disputed votes.
The failure to reach a compromise, for now, appears to be hurting Obama's general election chances.
Early polling shows Obama trailing McCain by a wide margin in Florida and a tight race in Michigan, while Clinton handily beats McCain in Florida.
Obama has been working to repair that damage in the past couple of weeks, campaigning in Florida for the first time this year and holding foreign policy speeches before its large Cuban-American community as well as Jewish groups.
The fine details of the US primary system have rarely taken on such a key role in an election.