President Joe Biden is not seeking reelection, he announced Sunday, bringing an unprecedented degree of uncertainty into the presidential election just weeks before the Democratic Party was set to renominate him. 

“It has been the greatest honor of my life to serve as your president,” Biden wrote in a letter addressed to his fellow Americans that he posted on X Sunday afternoon. “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.” The president also pledged to “speak to the Nation later this week in more detail” about his decision.

In a subsequent tweet, Biden endorsed Vice President Kamala Harris to succeed him as Democratic nominee. “Today I want to offer my full support and endorsement for Kamala to be the nominee of our party this year,” he posted.

Biden’s withdrawal from the race came after weeks of pressure from fellow Democrats—including elected officials, candidates, and donors—for the 81-year-old president to step aside. The June 27 presidential debate, in which Biden struggled to speak coherently, prompted the slew of public and private conversations to urge him to reconsider his reelection bid. The emerging picture from post-debate polling demonstrated that Biden was performing worse in nearly every key swing state and risked sinking fellow Democrats in races down the ballot. And the forthcoming Democratic National Convention, which begins in less than a month, meant there was relatively little time to make a change to the ticket before Biden would be formally nominated.

What happens next remains unclear, even with Biden’s support for Harris. Democratic National Committee Chair Jaime Harrison issued a statement Sunday afternoon promising to hear “in short order” from the party “on next steps and the path forward.” While some party bigwigs quickly followed Biden’s lead and endorsed Harris, it’s hardly a guarantee that the vice president will simply be handed the Democratic nomination. Former President Barack Obama, for example, issued a lengthy statement on Sunday afternoon that did not mention Harris by name—only that he was confident that “the leaders of our party will be able to create a process from which an outstanding nominee emerges.”

And what Biden’s withdrawal from the race means for the general election is, at this point, anyone’s guess. Republicans, who had been raising the issue of Biden’s advanced age for months before the June debate, have suggested in recent days they would push back or challenge any efforts by Democrats to replace Biden. Hours before the president’s announcement Sunday, House Speaker Mike Johnson said on ABC News’ This Week that Republicans would legally challenge his withdrawal.

But Biden’s erstwhile opponent, newly nominated Republican standard bearer Donald Trump, appears to believe replacing Biden will not harm his current advantage in the polls. “Crooked Joe Biden is the Worst President, by far, in the History of our Nation,” he posted on Truth Social Sunday afternoon. “He was not fit to serve from the very beginning, but the people around him lied to America about his Complete and Total Mental, Physical, and Cognitive Demise. Whoever the Left puts up now will just be more of the same.”

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