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.

The decision comes after escalating pressure from Biden’s Democratic allies to step aside following the June 27 debate, in which the 81-year-old president trailed off, often gave nonsensical answers and failed to call out the former president’s many falsehoods.

Biden plans to serve out the remainder of his term in office, which ends at noon on Jan. 20, 2025.

“It has been the greatest honor of my life to serve as your President. And while it has been my intention to seek reelection, I believe it is in the best interest of my party and the country for me to stand down and to focus solely on fulfilling my duties as President for the remainder of my term,” Biden wrote in a letter posted to his X account.

New Hampshire’s all-Democratic Congressional delegation had dodged taking a position on whether Biden should remain in the race or step down. On Sunday, they thanked him for his service.

“From fixing our nation’s broken infrastructure systems to strengthening our global alliances in the face of unprecedented challenges to enacting the most sweeping climate change legislation to getting our country to the other side of the COVID pandemic, President Biden should be proud of the progress America has made under his leadership,” Sen. Jeanne Shaheen said in a statement. “As he always has, President Biden is once again putting the country he loves first, and I thank him for his unwavering dedication and service to our nation.”

Congressman Chris Pappas, who represents the state’s first congressional district, was the only member of the state’s delegation who encouraged Biden to reconsider. On Sunday, he said he agreed with Biden’s decision.

“The stakes in this election could not be higher, and this moment requires us to be forward-looking and put the needs of everyday Americans front and center,” Pappas said. “This election is about more than one candidate on the ballot.”

Congresswoman Annie Kuster, who is not running for re-election to represent the state’s second congressional district, was the first on Sunday to endorse Vice President Kamala Harris.

“Over the last several years, I have had the privilege of working closely with Vice President Harris as she has grown into one of the most effective and influential vice presidents in American history,” Kuster said in a statement. “I have full confidence in her ability to unite Democrats, Independents, and reasonable Republicans to defeat Donald Trump and the disastrous policies his administration would enact on the American people.”

Sen. Maggie Hassan said Biden’s presidency will last as “one of the most effective in our lifetimes.” She has not yet endorsed Harris but reemphasized the importance of beating Trump.

“The task before us now is to focus on defeating Donald Trump in November, and I am committed to continuing that work. Our American democracy needs to remain strong and vibrant to deliver real results for the people of America, just as Joe Biden has done,” Hassan said in a statement to the Monitor.

Biden’s decision came as he has been isolating at his Delaware beach house after being diagnosed with COVID-19 last week, huddling with a shrinking circle of close confidants and family members about his political future. Biden said he would address the nation later this week to provide “detail” about his decision.

The announcement is the latest jolt to a campaign for the White House that both political parties see as the most consequential election in generations, coming just days after the attempted assassination of Trump at a Pennsylvania rally.

A party’s presumptive presidential nominee has never stepped out of the race so close to the election. The closest parallel would be President Lyndon Johnson who, besieged by the Vietnam War, announced in March 1968 that he would not seek another term.

Now, Democrats have to urgently try to bring coherence to the nominating process in a matter of weeks and persuade voters in a stunningly short amount of time that their nominee can handle the job and beat Trump. And for his part, Trump must shift his focus to a new opponent after years of training his attention on Biden.

The decision marks a swift and stunning end to Biden’s 52 years in electoral politics, as donors, lawmakers and even aides expressed to him their doubts that he could convince voters that he could plausibly handle the job for another four years.

Biden won the vast majority of delegates and every nominating contest but one, which would have made his nomination a formality. Now that he has dropped out, those delegates will be free to support another candidate.

Harris, 59, appeared to be the natural successor, in large part because she is the only candidate who can directly tap into the Biden campaign’s war chest, according to federal campaign finance rules.

The Democratic National Convention is scheduled to be held Aug. 19-22 in Chicago, and Harris would likely have competition from others looking to replace Biden. That could create a scenario in which she and others end up lobbying individual state delegations at the convention for their support.

In 2020, Biden pitched himself as a transitional figure who wanted to be a bridge to a new generation of leaders. But once he secured the job he spent decades struggling to attain, he was reluctant to part with it.

Biden was once asked whether any other Democrats could beat Trump.

“Probably 50 of them,” Biden replied. “No, I’m not the only one who can defeat him, but I will defeat him.”

Biden is already the country’s oldest president and had insisted repeatedly that he was up for the challenge of another campaign and another term, telling voters all they had to was “watch me.”

And watch him they did. His poor debate performance prompted a cascade of anxiety from Democrats and donors who said publicly what some had said privately for months, that they did not think he was up to the job for four more years.

Concerns over Biden’s age have dogged him since he announced he was running for re-election, though Trump is just three years younger at 78. Most Americans view the president as too old for a second term, according to an August 2023 poll from The Associated Press-NORC Center for Public Affairs Research. A majority also doubt his mental capability to be president, though that is also a weakness for Trump.

But voters had other problems with him, too — he has been deeply unpopular as a leader even as his administration steered the nation through recovery from a global pandemic, presided over a booming economy and passed major pieces of bipartisan legislation that will impact the nation for years to come. A majority of Americans disapprove of the way he’s handling his job, and he’s faced persistently low approval ratings on key issues including the economy and immigration.

Biden’s motivation for running was deeply intertwined with Trump. He had retired from public service following eight years serving as vice president under Barack Obama and the death of his son Beau but decided to run after Trump’s comments following a “Unite the Right” rally in Charlottesville, Virginia, in 2017, when white supremacists descended on the city to protest the removal of its Confederate memorials.

Trump said: “You had some very bad people in the group, but you also had people that were very fine people on both sides. On both sides.”

That a sitting president didn’t unequivocally condemn racism and white supremacy deeply offended Biden.

“If Trump wasn’t running, I’m not sure I’d be running,” Biden once said during at a campaign event.

Concord Monitor reporter Charlotte Matherly contributed to this report.