"The celebrities will be next. I guess Oprah will call me."
In just the past two weeks, more than two dozen of them have climbed aboard his presidential campaign, according to a survey by The Associated Press. At the same time, Hillary Rodham Clinton's are beginning to jump ship, abandoning her for Obama or deciding they now are undecided.
The result: He's narrowing her once-commanding lead among these "superdelegates," the Democratic office holders and party officials who automatically attend the national convention and can vote for whomever they choose.
As Obama has reeled off 11 straight primary victories, some of the superdelegates are having second — or third — thoughts about their public commitments.
Take John Perez, a Californian who first endorsed John Edwards and then backed Clinton. Now, he says, he is undecided.
"Given where the race is at right now, I think it's very important for us to play a role around bringing the party together around the candidate that people have chosen, as opposed to advocating for our own choice," he said in an interview.
Clinton still leads among superdelegates — 241 to 181, according to the AP survey. But her total is down two in the past two weeks, while Obama's is up 25. Since the primaries started, at least three Clinton superdelegates have switched to Obama, including Rep. David Scott of Georgia, who changed his endorsement after Obama won 80 percent of the primary vote in Scott's district. At least two other Clinton backers have switched to undecided.
None of Obama's have publicly strayed, according to the AP tally.
There are nearly 800 Democratic superdelegates, making them an important force in a nomination race as close as this one. Both campaigns are furiously lobbying them.
"Holy buckets!" exclaimed Audra Ostergard of Nebraska. "Michelle Obama and I are playing phone tag."
Billi Gosh, a Vermont superdelegate who backs Clinton, got a phone call from the candidate herself this week.
"As superdelegates, we have the opportunity to change our mind, so she's just connecting with me," Gosh said. "I couldn't believe she was able to fit in calls like that to her incredibly busy schedule."
In Utah, two Clinton superdelegates said they continue to support the New York senator — for now.
"We'll see what happens," said Karen Hale. Likewise, fellow superdelegate Helen Langan said, "We'll see."
Other supporters are more steadfast.
"She's still in the race, isn't she? So I'm still supporting her," said Belinda Biafore, a superdelegate from West Virginia.
Obama has piled up the most victories in primaries and caucuses, giving him the overall lead in delegates, 1,362 to 1,266.5. Clinton's half delegate came from the global primary sponsored by the Democrats Abroad.
It will take 2,025 delegates to secure the nomination at this summer's national convention in Denver. If Clinton and Obama continue to split delegates in elections, neither will reach the mark without support from the superdelegates.
That has the campaigns fighting over the proper role for superdelegates, who can support any candidate they want. Obama argues it would be unfair for them to go against the outcome of the primaries and caucuses.
"I think it is important, given how hard Senator Clinton and I have been working, that these primaries and caucuses count for something," Obama said during Thursday night's debate in Austin, Texas.
Clinton argues that superdelegates should exercise independent judgment.
"These are the rules that are followed, and you know, I think that it will sort itself out," she said during the debate. "We will have a nominee, and we will have a unified Democratic Party, and we will go on to victory in November."
Behind the scenes, things can get sticky.
David Cicilline, the mayor of Providence, R.I., indicated this week that his support for Clinton might be wavering after — he contended — members of her campaign urged him to cave to the demands of a local firefighters union ahead of her weekend appearance there. The firefighters, in a long-running contract dispute with Cicilline, have said they would disrupt any Clinton event the mayor attends. A Clinton spokeswoman said the campaign would never interfere in the mayor's city decisions.
Obama has been helped by recent endorsements from several labor unions, including the Teamsters on Wednesday.
"He's our guy," said Sonny Nardi, an Ohio superdelegate and the president of Teamsters Local 416 in Cleveland.
The Democratic Party has named about 720 of its 795 superdelegates. The remainder will be chosen at state party conventions in the spring. AP reporters have interviewed 95 percent of the named delegates, with the most recent round of interviews taking place this week.
The superdelegates make up about a fifth of the overall delegates. As Democratic senators, both Clinton and Obama are superdelegates.
So is Cincinnati Mayor Mark Mallory, which is one reason his phone rings often.
He is a black mayor, and Obama has been winning about 90 percent of black votes. His state has a March 4 primary with 141 delegates at stake. The Democratic governor, Ted Strickland, is stumping hard for Clinton — and perhaps a spot on the national ticket.
A phone call from former President Clinton interrupted Mallory's dinner on a recent Saturday.
"I continue to get calls from mayors, congresspeople, governors, urging me one way or another," said Mallory, who is still mulling his decision.