FACTBOX: Democrats seek endgame in White House race

(Reuters) - The Democratic race between Sens. Hillary Clinton of New York and Barack Obama of Illinois is likely to extend into June with neither candidate winning enough delegates to clinch the presidential nomination.

Obama has a nearly insurmountable lead among pledged delegates who will help decide the candidate to face Republican John McCain in the November election.

But with 10 nominating contests remaining until June 3, it is unlikely either candidate can reach the 2,025 needed to become the nominee. Following are some potential scenarios for settling the Democratic race:

* With Obama and Clinton stalled short of the magic number, the race could be decided by nearly 800 superdelegates -- party officials and insiders who are free to back any candidate.

About 330 superdelegates remain uncommitted to either candidate, and if a big majority move to one candidate they could settle the race. The candidates have chased their support, but many superdelegates are postponing decisions until the nominating contests finish.

* Florida and Michigan were stripped of their delegates in a dispute with the national party, but held unsanctioned contests won by Clinton although no candidates campaigned in the states and Obama was not on Michigan ballot.

Clinton has called for seating the delegates, which would probably still leave her trailing Obama but would bolster her case to superdelegates that she is the candidate with the best chance to win in November.

Obama says he will work with the Democratic National Committee to find a mutually agreeable solution, but opposes the seating of the delegates from the unsanctioned contests.

The national party says it will not change the rules at this late stage, and party officials in both states are seeking ways to conduct revotes that would allow delegates to be seated. A Florida Democratic plan for a mail-in revote has already attracted significant opposition.

* With many of the superdelegates still undecided, the party could go to the nominating convention in Denver in August without a clear winner.

Party leaders, fearing the resulting chaos and damage to the party, have vowed to work to bring the race to a close before then. The prospect of a brokered convention, however, has led to speculation on a variety of scenarios.

Uncommitted Democrats like Al Gore and former candidates John Edwards and Joseph Biden could step in and convince either Obama or Clinton to step aside for the good of the party.

In a much more unlikely scenario, delegates could turn to a prominent Democrat like Gore and ask him to be the nominee.