Others, though, say a series of smaller superdelegate meetings has begun -- virtually -- to unite the party behind one candidate and avoid a summer-long and convention fight between Sen. Hillary Clinton, D-N.Y., and Sen. Barack Obama, D-Ill., The Politicoo reported Tuesday.

Clinton and her supporters argue that she should continue campaigning; opponents and members from Obama's camp say she should bow out for the good of the party. Obama says she should remain in the campaign.

The virtual exchanges include pleas from Obama advocates to end the race early and Clinton supporters urging more time and warning of his general election vulnerabilities, The Politico said.

In a recent Politico interview, U.S. of Representatives House Majority Whip Rep. James Clyburn, D-S.C., said he wouldn't take sides in the primary race. But he said he believed that all superdelegates should reach a decision by June on whom they would support.

Democratic National Committee Chairman Howard Dean said he'd like to see the superdelegates commit by July 1, after the primary season ends.

The Democratic National Convention is set for Aug. 25-28 in Denver.