President Joe Biden dropped out of the 2024 race for the White House on Sunday, ending his bid for reelection following a disastrous debate with Donald Trump that raised doubts about his fitness for office just four months before the election.

Meanwhile, Vice President Kamala Harris is being thrust into the most scrutinizing of spotlights, suddenly the leading candidate to succeed Biden as the presumptive Democratic presidential nominee and her party's main hope of defeating Trump.

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Here's the Latest:

Sen. Kirsten Gillibrand of New York endorses Harris

Sen. Kirsten Gillibrand, a Democrat from New York, endorsed Harris and called her "an unwavering champion for families, workers and justice."

Gillibrand, who ran against Harris in the 2020 Democratic presidential primary, said in a statement Monday that the vice president is "incredibly well-qualified, with experience as a prosecutor, as a lawmaker, and as a leader on the world stage."

"Now is the time to unite," the senator said. "VP Harris has the grit and toughness to beat Donald Trump and I'm eager to join her in this fight."

Small-dollar donations total $46.7 million for Harris

ActBlue, the Democratic fundraising platform, announced that it had collected $46.7 million as of 9 p.m. ET from small-dollar donations for Vice President Harris' campaign.

The Biden campaign and affiliated groups previously had about $96 million in cash on hand. The Republican National Convention, by contrast, reported a campaign fund of $102 million in June.

Trump's campaign quickly pivots to Harris after Biden withdraws

Donald Trump's campaign has spent the last year and a half viciously attacking Joe Biden, ridiculing his policies, mocking his fumbles and relishing a rematch they felt they were winning.

But it has also spent weeks preparing for the possibility that he might exit the race, readying a bevy of attacks against Vice President Kamala Harris that it unleashed as soon as Biden made his stunning announcement Sunday that he would step aside.

Biden soon after endorsed Harris, who was quickly winning support from Democrats to be the party's nominee.

The shakeup less than four months before Election Day lays out new challenges for Trump's team, which had until recently been focused on contrasting the former president's vigor and mental acuity with Biden's.

Read more about the Trump campaign's pivot toward Harris.

Some states' convention delegates begin shifting support to Harris

The Democratic delegations of multiple states have decided to back Vice President Kamala Harris for the party nomination at next month's national convention.

"Tonight, all 168 delegates of the North Carolina Democratic Party made history," North Carolina party chair Anderson Clayton said in a post on the social platform X.

In South Carolina, party chair Christale Spain said in an email statement Sunday night that that state's delegation met virtually. The vice president "has been fully vetted, and she has earned our unwavering support," Spain said.

Harris received her first delegates earlier in the day from Tennessee, when the state party posted on X that its delegation voted during a meeting to back her.

Another state where the switch was made was New Hampshire, where the 25 pledged delegates voted unanimously Sunday night to endorse Harris.

Black state attorneys general back Harris

The nation's six Black state attorneys general threw their support behind Vice President Harris. In a statement on X, they laid out her qualifications and said she "has staunchly defended our right to choose and preserved our most sacred right to vote. There is no one more qualified to lead and continue to uphold the values of our great nation."

The statement listed Letitia James, New York; Kwame Raoul, Illinois; Anthony Brown, Maryland; Andrea Campbell, Massachusetts; Keith Ellison, Minnesota; and Aaron Ford, Nevada.

Democrats promise 'orderly process' to replace Biden. Harris is favored, but questions remain

Shortly after President Joe Biden announced that he would drop his reelection campaign, Democratic National Committee Chair Jaime Harrison had a message: There would be no automatic coronation for his replacement.

"In the coming days, the party will undertake a transparent and orderly process to move forward," Harrison said in a statement. "This process will be governed by established rules and procedures of the party. Our delegates are prepared to take seriously their responsibility in swiftly delivering a candidate to the American people."

The comment reflected the reality that while Vice President Kamala Harris is emerging as the prohibitive favorite to become the nominee — backed already by Biden and many Democrats — it's not so simple. And for now, the party isn't offering many details on what happens next.

Read more about the process of replacing Biden on the Democratic ticket.