Why some top Democrats are holding back on Kamala Harris endorsements

In the hours since U.S. President Joe Biden bowed out of the presidential campaign, dozens of Democratic governors, donors, lawmakers and potential opponents came out swinging in support of Vice-President Kamala Harris as their would-be candidate.

But some of the party's most prominent heavyweights have held back — from Senators Chuck Schumer and Hakeem Jeffries to former U.S. president Barack Obama, who issued statements supporting Biden but stopped short of an endorsement for Harris.

As of Monday night, Harris had secured the support of enough Democratic delegates to become her party's nominee against Republican Donald Trump, according to an Associated Press survey. 

"I have extraordinary confidence that the leaders of our party will be able to create a process from which an outstanding nominee emerges," Obama said in a statement Sunday, which did not mention Harris. 

Professors in American history and political science say some key Democratic leaders might be holding out on endorsements not because they doubt Harris or expect another challenger, but because they don't want to be seen as influencing the outcome of a race that's been upended so late in the game.

"I think they want to give the impression that the party gets the chance to make a decision without it being dictated by the elites of the party," said Paul Quirk, a professor of political science at the University of British Columbia. 

"I've seen no grounds for thinking that any of them actually would oppose her candidacy and, in particular, there hasn't been anyone else who seems likely to emerge."

Several state delegations met late Monday to confirm their support for Harris, including Texas and her home state of California. By Monday night, she had the support of at least 2,471 delegates, according to an AP tally, more than the 1,976 she'll need to win on a first ballot. No other candidate was named by a delegate contacted by AP.

Despite this, AP is not calling Harris the new presumptive nominee. That's because delegates are still free to vote for the candidate of their choice at the Democratic National Convention (DNC) in August, or if Democrats go through with a virtual roll call ahead of that gathering in Chicago.

Schumer, the majority leader, and Jeffries, the minority leader, said in a joint statement that Harris was off to a "great start with her promise to pursue the presidential nomination in a manner consistent with the grassroots and transparent process set forth by the Democratic National Committee."

"Vice-President Kamala Harris has excited the community, she's excited the House Democratic caucus and she's exciting the country. I'm looking forward to sitting down with her, in person, in short order, with leader Schumer," Jeffries told reporters Monday, according to NBC's Meet The Press.

He said he'd have more to say about the path forward after that meeting.

Harris, 59, said in her own statement Sunday that she intends to "earn and win" a place at the top of the ticket.

Democrats including California Gov. Gavin Newsom, Michigan Gov. Gretchen Witmer and Transportation Secretary Pete Buttegieg — who were initially thought to be her most likely challengers — were quick to back Harris.