In her first day as a candidate, Harris raised $81 million, the campaign announced Monday, saying it was the largest 24-hour raise by any candidate ever. The huge haul underscored grassroots enthusiasm for a shake-up to the Democratic 2024 ticket. According to the campaign, more than 880,000 “grassroots supporters” donated, with 60% making their first contributions of the 2024 cycle.

Democratic donation-processing site ActBlue called it “the biggest fundraising day of the 2024 cycle.” The Democratic super PAC Future Forward secured $150 million in commitments from donors in the 24 hours after Biden announced his decision, a senior aide to the group said. The commitments came from donors who were either uncommitted, unsure or previously stalled, the aide added.

Four governors of must-win Midwestern states — Michigan’s Gretchen Whitmer, Minnesota’s Tim Walz, Wisconsin’s Tony Evers and Illinois’ JB Pritzker — have endorsed Harris. They join endorsements from Kentucky’s Andy Beshear, North Carolina’s Roy Cooper, California’s Gavin Newsom and Pennsylvania’s Josh Shapiro. Many of those governors could be considered for the party’s vice presidential nomination.

Meanwhile, the cascade of endorsements for Harris’ candidacy that had begun Sunday afternoon accelerated on Capitol Hill. Harris has the support of more than 40 Democratic senators and nearly 100 House members — numbers that had grown rapidly throughout Monday morning. A significant one came from former House Speaker Nancy Pelosi, who said in a Monday afternoon statement that her “enthusiastic support for Kamala Harris for President is official, personal and political.”

Senate Majority Leader Chuck Schumer and House Minority Leader Hakeem Jeffries, the top-ranking Democrats in each chamber, were set to endorse Harris soon, according to multiple sources familiar with the decision. Massachusetts Rep. Katherine Clark and California Rep. Pete Aguilar, the second- and third-ranking House Democrats, endorsed Harris on Monday morning.

She also has the support of the political arms of the Congressional Black Caucus, Congressional Hispanic Caucus and Congressional Progressive Caucus, as well as two key labor unions, Service Employees International Union and the American Federation of Teachers.

Support for the vice president came across the party’s ideological spectrum — from moderate populists, including Ohio Sen. Sherrod Brown, one of the most endangered Democratic incumbents on the ballot this fall, to progressives, including Massachusetts Sen. Elizabeth Warren and New York Rep. Alexandria Ocasio-Cortez.

The hour-by-hour endorsements of Harris from Democratic governors, senators, Cabinet officials and state delegations unfolded by design, with the hope of reaching a majority of delegates by Wednesday, two people familiar with the process tell CNN. Harris beat that timeline on Monday.

“It’s a coordinated drumbeat,” a senior Democratic aide working on the effort said. “That sound Democrats hear is the party uniting around the vice president.”

Delegate endorsements — which are not binding — continue to come in.

How Harris and her allies mobilized

Joe Biden’s 1:46 p.m. ET Sunday announcement that he would not seek a second term ignited a frenetic push by Harris to consolidate the support of a party that had been in crisis in the weeks since the president’s dismal performance during his June 27 debate with Trump.

Harris knew what Biden had decided: She’d had multiple phone calls with Biden on Sunday, a person familiar with the matter said. Once the announcement came, Harris — wearing a hoodie from her alma mater, Howard University, workout sweats and sneakers — made more than 100 phone calls over 10 hours.

Alongside her family and staff, the vice president’s calls included lawmakers, governors and leaders of influential labor, advocacy and civil rights groups.

Those calls included former Presidents Barack Obama and Bill Clinton, as well as former Secretary of State Hillary Clinton. The Clintons, in a statement Sunday, endorsed Harris; Obama did not, deferring to the party’s process.

Harris also called her pastor, Amos Brown III, who, along with his wife, prayed over her, the source said. She ate pizza with anchovies — Harris’ go-to topping — for dinner.

In those phone calls, Harris made clear that while she was grateful for Biden’s endorsement, she planned to earn the Democratic nomination in her own right. That echoes the statement she released following Biden’s announcement to step aside.

“I am honored to have the President’s endorsement and my intention is to earn and win this nomination,” she wrote.

Harris’ supporters were also mobilizing.

Harris’ chief of staff Lorraine Voles and California Lt. Gov. Eleni Kounalakis led a call Monday morning with around 350 Democratic donors, fundraisers and supporters, a longtime Democratic fundraiser and supporter of Harris for many years told CNN. The source, who was on the call, said by gathering Harris’ core supporters from her previous campaigns and newly interested donors, they hoped to get everyone to “row the right way.”

The group Win With Black Women periodically holds Zoom calls — but the one that took place Sunday evening had a different tone, with 44,000 people joining, according to its leaders.

Longtime Democratic operative Donna Brazile said that she was in the process of gathering delegates to support Harris. “I need all of you to sign your delegate pledge forms now,” Brazile said on the call. She said voter registration and fundraising will be key in the days ahead.

Washington, DC, Mayor Muriel Bowser also spoke on the call.

“I know what it’s like to be in the crosshairs of Donald Trump,” she said. “We have to defend our sister.”

Former Congressional Black Caucus Chairwoman Joyce Beatty and Texas Rep. Jasmine Crockett were also among the speakers.

No serious challenger materializes yet

No serious challenger has emerged to take on Harris for the nomination ahead of the Democratic National Convention, which starts August 19 in Chicago.

Any challenge might need to materialize even faster: The Democratic National Committee is moving forward with a process that will determine the party’s presidential nominee by August 7, party officials said Monday night.

Manchin, who had left the party earlier this year and is not seeking reelection, said Monday he will not rejoin the party and seek its nomination.

CNN has previously reported the West Virginia senator was considering re-registering as a Democrat to throw his hat in the ring. But in an interview with CBS News on Monday, Manchin said he will not be a candidate.

“I could not believe that there was not going to be a primary process or a mini process. Other countries do it,” Manchin said, adding that he believes Harris is too liberal but could be forced to the middle if she faces a challenge.

New York City Democratic Mayor Eric Adams announced his support for Harris in an interview with MSNBC on Monday, reversing course just hours after he told CNN, “there’s a process and we’re going to follow that process,” to determine the party’s nominee.

“We need real, clear, leadership, and she understands it,” Adams told MSNBC. “She was in the position of looking over the border issue, so she understands some of the things that we need to do.”

And he offered a stirring endorsement of Harris’ fitness to lead the ticket, urging advisers to “let her be her.”

Running mate jockeying begins

Democratic lawyers are beginning their work conducting a deep, yet truncated, vetting process for potential vice presidential hopefuls, two people familiar with the matter told CNN, with siloed teams being established for the leading prospective candidates.

Cooper, Shapiro and Arizona Sen. Mark Kelly are among the Democrats who have been asked to submit information about their finances, family histories and other personal details, two people familiar with the process said. They are part of a group that includes about 10 names, nearly all of whom are elected officials.

Former Attorney General Eric Holder and his law firm Covington & Burling will handle vetting for Harris’ running mate, a source familiar with the plans said.

The audition process is also playing out in public, with Cooper and Beshear appearing on MSNBC’s “Morning Joe” on Monday — with the intent that Harris was watching. An aide said she caught at least part of the conversations.

Beshear, the two-term Kentucky governor, announced his support for Harris — and said he is open to joining Harris as her potential running mate, noting it’s “flattering to be a part” of the conversation about the vice-presidential nomination.

He also offered a window into how he’d play the traditional attack-dog role of a running mate. At multiple points in the interview, Beshear attacked Republican vice presidential nominee JD Vance, who has family ties to Beshear’s home state of Kentucky.

“Let me just tell you that JD Vance ain’t from here,” Beshear said, referring to his home state, taking issue with how Vance described Appalachia in his best-selling memoir “Hillbilly Elegy.”

Beshear also attacked Vance for past comments expressing support for strict restrictions to abortion access, while touting Harris’ record of supporting protections for reproductive health care.

“JD Vance calls pregnancy arising from rape ‘inconvenient,’” Beshear said. “No, it’s just plain wrong. He suggests that women should stay in abusive relationships. Now listen, a domestic abuser isn’t a man, he’s a monster, and no one should support anyone having to stay in those relationships.”

Cooper, the North Carolina governor who endorsed Harris on Sunday, also appeared on MSNBC on Monday, but deflected questions about whether he would be open to becoming her running mate.

“I think it’s really important that we do keep the focus on her this week. The vice-presidential conversation needs to occur later,” Cooper said. “I want to make sure that Kamala Harris wins. I’m going to work for her all over this country and do what I can to make sure we stop Donald Trump.”

Whitmer, the Michigan governor, told a local reporter she’s “not planning to go anywhere” when asked Monday if she would accept the vice presidential role if offered.

Colorado Gov. Jared Polis, meanwhile, told CNN’s Dana Bash that “obviously, if somebody asks, I’d take a serious look at it,” but that “my phone hasn’t rung yet.”

“If they do the polling and it turns out that they need a 49-year-old, balding, gay Jew from Boulder, Colorado, they got my number,” Polis quipped.

This story and headline have been updated with additional reporting.

CNN’s Jeff Zeleny, Jamie Gangel, Ebony Davis, Aaron Pellish, MJ Lee, DJ Judd, Eva McKend, Arlette Saenz and Alison Main contributed to this report.