Obama picks up 6 superdelegates, union endorsement

"Our people, I think, recognize the enthusiasm and vitality behind Senator Obama's campaign," he said in a statement.

"After careful consideration, I have reached the conclusion that Barack Obama can best bring about the change that our country so desperately wants and needs," said Payne, who in a statement said that Clinton is a good friend and he still holds her in high regard.

Payne is one of at least 10 superdelegates who have switched allegiances from Clinton to Obama. None have publicly switched the other way.

In the overall race for the nomination, Obama leads with 1,857.5 delegates, to 1,697 for Clinton. Obama is just 167.5 delegates short of the 2,025 delegates needed to win it.

Clinton's new supporter was Rep. Chris Carney, D-Pa. His congressional district voted overwhelmingly for the former first lady in the Pennsylvania primary on April 22.

Both Obama and Clinton have courted superdelegates in recent days in private meetings at party headquarters not far from the Capitol.

Despite Watkins' assessment, Clinton has shown no signs she is ready to quit the race. She is heavily favored to win Tuesday's primary in West Virginia, and is in the midst of a two-day swing through several other states with upcoming elections.

___

Associated Press Writers Jesse Holland and Matthew Daly in Washington and Solvej Schou in Los Angeles contributed to this report.