Many Democrats on Sunday quickly backed Vice President Kamala Harris to run as the party’s presidential nominee against Donald Trump after President Joe Biden’s abrupt departure from the race, but some powerful party members, including former President Barack Obama and former House Speaker Nancy Pelosi, stayed quiet.

After weeks of fighting among Democrats on whether Biden, 81, should stay in the race, a rush of support coalescing behind Harris, if she is to be the nominee, is crucial with just over 100 days before the November election.

But there are plenty of doubts inside the Democratic Party about whether Harris can beat Trump, the Republican nominee and former president. Some Democrats have suggested the party should hold a mini-primary before the August convention.

Biden himself endorsed Harris on Sunday, in a separate statement following his letter saying that he is stepping down. He was quickly followed by the powerful Congressional Black Caucus, several key donors, various lawmakers and super PACs including Priorities USA and Unite the Country.

“Today I want to offer my full support and endorsement for Kamala to be the nominee of our party this year,” Biden said on social media platform X. “Democrats — it’s time to come together and beat Trump. Let’s do this.”

The list of Democratic lawmakers endorsing Harris grew as the day progressed. By Sunday evening, the list included California Gov. Gavin Newsom, Colorado Gov. Jared Polis, North Carolina Gov. Roy Cooper, Pennsylvania Gov. Josh Shapiro, U.S. Sen. Mark Kelly of Arizona, U.S. Sen. Patty Murray of Washington state, U.S. Rep. James Clyburn of South Carolina, and U.S. Rep. Pramila Jayapal of Washington.

Dmitri Mehlhorn, an adviser to Reid Hoffman, the LinkedIn founder and a major Democratic donor, called Harris “the American dream personified,” noting she is the daughter of immigrants. “She is also toughness personified, rising from my home town of Oakland California to become the top prosecutor of the state. With Scranton Joe stepping back, I cannot wait to help elect President Harris.”

All 50 Democratic party state chairs will support Harris as the party’s new presidential nominee, Reuters reported on Sunday, citing multiple sources. The Democratic delegations to the nominating convention from Tennessee, Louisiana, South Carolina and North Carolina said they support Harris.

Former President Bill Clinton and Hillary Clinton, who served as secretary of State under President Obama, also endorsed Harris in a statement.

Still, others, including Pelosi and Obama, under whom Biden served as vice president for eight years, thanked Biden for his patriotism but did not yet throw their support behind Harris or any other candidate.

“We will be navigating uncharted waters in the days ahead,” Obama said in a statement. “But I have extraordinary confidence that the leaders of our party will be able to create a process from which an outstanding nominee emerges.”

Just as he did in 2020 once Biden earned the Democratic nomination, Obama said he believes he will be uniquely positioned to help unite the party once it has a nominee, said a source familiar with the matter.

Senate Majority Leader Chuck Schumer, who praised Biden’s decision to step aside, also was silent on who should be the Democrats’ nominee.

U.S. Sen. Peter Welch, the first Democratic senator to call on Biden to drop his reelection run, called for an open nomination process.

The Democrats should have “an open process so that whoever our nominee is, including Kamala, has the strength of having a process that shows the consensus position of the party,” Welch said. “The debate in the Democratic Party is who can carry on the legacy of President Biden and defeat Trump.”

One Democratic donor told Reuters they would support a ticket for Harris as the presidential candidate and Pennsylvania Gov. Josh Shapiro as her vice president, as a way to gain votes in Pennsylvania, a critical swing state. It is not known yet whom Harris would pick as her vice president if she does become the nominee.

And a group appealing to supporters of former Republican presidential candidate Nikki Haley who had been backing Biden under the name Haley Voters for Biden, changed its name on Sunday to Haley Voters for Harris.