WASHINGTON — Vice President Kamala Harris is one step closer to becoming the nation’s first female commander-in-chief after President Biden dropped off the Democratic ticket on Sunday — but the former California senator and attorney general is still not guaranteed to secure her party’s nomination as its Plan B 2024 contender.

In a post sent minutes after he dropped out of the running for president, Biden, 81, wrote on X: “My very first decision as the party nominee in 2020 was to pick Kamala Harris as my Vice President. And it’s been the best decision I’ve made.

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

Meanwhile, Bill and Hillary Clinton wasted little time throwing their support behind Harris, 59, despite being among the few big-name Democrats still urging Biden to stay in the race in recent days.

“We’ve lived through many ups and downs, but nothing has made us more worried for our country than the threat posed by a second Trump term,” they said in a joint statement.

“Now is the time to support Kamala Harris and fight with everything we’ve got to elect her. America’s future depends on it.”

The Clintons were quickly joined by a flood of Democratic luminaries in rallying behind Harris, including Democratic Sens. Elizabeth Warren (D-Mass.), Patty Murray (D-Wash.), Mark Warner (D-Va.), Mark Kelly (D-Ariz.) and Tina Smith (D-Minn.)

She also quickly garnered the support of progressives in the house, among them Rep. Pramila Jayapal (D-Wash.), Rep. Jared Huffman (D-Calif.) and far-left “Squad” members Rep. Cori Bush (D-Mo.) and Ilhan Omar (D-Minn.)

Joining the mix of moderate and liberal congressional Democrats in supporting the switcheroo include Rep. Nanette Barragan (D-Calif.), who heads the Congressional Hispanic Caucus, and influental veteran Rep. James Clyburn (D-SC).

Democratic megadonors George and Alex Soros also endorsed Harris to take Biden’s place at the top of the ticket.

“It’s time for us all to unite around Kamala Harris and beat Donald Trump. She is the best and most qualified candidate we have,” Alex Soros wrote on X. 

But despite several Democratic boosters pledging to back her candidacy, there was a deafening silence from several party A-listers who withheld making an endorsement in their public statements praising Biden for his decision.

Former House Speaker Nancy Pelosi didn’t even mention Harris in her sendoff statement to President Biden on X, calling him “one of the most consequential presidents in American history.”

Another Democratic heavy hitter whose endorsement was conspicuously absent is former President Barack Obama, who praised Biden in a statement but stopped short of saying he’d approve of Harris as a candidate.

“We will be navigating uncharted waters in the days ahead,” said Obama, 62. “But I have extraordinary confidence that the leaders of our party will be able to create a process from which an outstanding nominee emerges.”

What to know about President Biden's decision to drop out of the 2024 presidential race:

• President Biden announced Sunday he is dropping out of the 2024 presidential race — after weeks of prominent Democrats and donors calling on him to withdraw following his disastrous performance in the first presidential debate.
• In a letter posted on X Sunday afternoon, Biden admitted that it is in the “best interest of my party and country” for him to step down as the Democratic nominee.
• Biden wrote that he intends to serve out the remainder of his term and will address the country on his decision later this week.
• In a follow-up X post, Biden endorsed Vice President Kamala Harris for the suddenly open Democratic nomination. “Today I want to offer my full support and endorsement for Kamala to be the nominee of our party this year,” the president wrote.
• Former President Donald Trump reacted to the news by labeling Biden the “worst president in the history of our country” in a call with CNN.

New York’s top Democrats have also withheld their public support for now, with House Minority Leader Hakeem Jeffries and Senate Majority Leader Chuck Schumer both issuing statements thanking Biden for his years of service but stopping short of giving Harris their blessing.

In her own statement, Harris said she was “honored” to have Biden’s endorsement — but made it clear that her “intention” is to “earn and win this nomination,” while studiously avoiding crowning herself as the presumptive nominee.

The former prosecutor, California attorney general and US senator has long sought to clinch the top spot on the Democratic ticket. She initially ran against Biden for the presidency in the 2020 election before dropping out and joining his slate as vice president later that year.

Biden stepped aside from the Democratic effort after hordes of prominent party leaders clamored for weeks over concerns about the elderly president’s mental acuity and electability following a disastrous performance at his June 27 debate against former President Donald Trump.

Throughout the debate, Biden froze, stumbled over his words and frequently lost his train of thought. Nonetheless, Harris repeatedly claimed the octogenarian could continue to serve another four years — despite the fact that he would have been 86 by the time he finished a second term.

Harris is a top choice and presumed front-runner to replace Biden on the ballot, given that she could most easily inherit the millions of dollars raised to re-elect the Biden-Harris ticket.

However, some Democrats fear Harris could further diminish the party’s chances against the former president in the Nov. 5 election.

Democratic favorites, such as Michigan Gov. Gretchen Whitmer and California Gov. Gavin Newsom, have been pitched as potential replacements given Harris’ poor polling during her time as vice president.

The nearly 4,000 delegates pledged to the Biden-Harris ticket have only five weeks or so to rally around a new candidate ahead of the Democratic National Convention, which is slated to take place in Chicago from Aug. 19-22.

Democratic National Committee Chairman Jaime Harrison promised Sunday to have a “transparent and orderly process” to select President Biden’s replacement as the presumptive nominee.

“The work that we must do now, while unprecedented, is clear,” Harrison said, without delving into how the process would unfold. 

“In the coming days, the Party will undertake a transparent and orderly process to move forward as a united Democratic Party with a candidate who can defeat Donald Trump in November.”

Harrison, however, didn’t explicitly endorse Harris.

Meanwhile, Illinois Gov. JB Pritzker, Kentucky Gov. Andy Beshear and former first lady Michelle Obama have also all previously been floated as possible replacements for Biden.

Throughout her reign as VP, Harris has championed abortion rights. She was also tasked by Biden to become the “border czar” overseeing the immigration crisis at the southern border — a job at which she failed miserably as illegal immigration numbers have boomed to historic levels throughout the course of the Biden administration.

The Trump campaign publicly asserted Harris would become the Democratic nominee for the first time on Wednesday, issuing a statement that Trump’s VP pick, Sen. JD Vance (R-Ohio), would not agree to a vice presidential debate until Harris’ role became clear.

“We don’t know who the Democrat nominee for Vice President is going to be, so we can’t lock in a date before their convention,” said Brian Hughes, a senior adviser to the Trump campaign. “To do so would be unfair to Gavin Newsom, JB Pritzker, Gretchen Whitmer, or whoever Kamala Harris picks as her running mate.”