After weeks of stalling and denials, President Joe Biden dropped out of the 2024 race in a letter posted to his personal Xitter account Sunday.

"It has been the greatest honor of my life to serve as your President,” Biden said in the letter, posted at 10:46 am Pacific Time/1:46 Eastern. "And while it has been my intention to seek re-election, 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."

It is a historic moment, and Biden said he would be addressing the nation, presumably on television, "later this week in more detail about my decision."

Only 19 hours earlier, Biden had posted a clip to X of Donald Trump calling this "the most important election" in our nation's history, saying that Trump had "told the truth for once," and insisting, "I will win it."

The letter stopped short of endorsing Vice President Kamala Harris, only saying, "I want to thank Vice President Kamala Harris for being an extraordinary partner in all this work."

But within an hour, Biden offered his endorsement of Harris, and former President Bill Clinton and former Secretary of State Hillary Clinton issued their joint endorsement of Harris as well.

Biden's decision, which has been widely expected but delayed now for weeks, throws the election into chaos. The last time a sitting president opted out of running for a second term was in 1968, when Lyndon B. Johnson announced he would not be running. But this is the latest in an election cycle that any sitting president has dropped out of the race.

The New York Times notes Biden's signature achievements today as he announces an end to his political career, saying, "he pushed through a $1.7 trillion Covid-19 relief package; a $1 trillion program to rebuild the nation’s roads, highways, airports and other infrastructure; and major investments to combat climate change, lower prescription drug costs for seniors, treat veterans exposed to toxic burn pits and build up the nation’s semiconductor industry. He also signed legislation meant to protect same-sex marriage in case the Supreme Court ever reversed its decision legalizing it."

Harris, who began her career in San Francisco city politics, ultimately becoming district attorney and then Attorney General of California before joining the Senate, begins what will now be a chaotic race for the White House in the strongest position, with access to the Biden ticket's campaign funds.

However, we are now just four weeks out from the Democratic National Convention, at which the party's nomination will be decided for the first time in over 70 years. The 1952 DNC was the last brokered convention, which were fairly common up until 1968. That year, party rules changed, and the party united around a single candidate, Hubert Humphrey, following the assassination death of Robert F. Kennedy.

This led to protests and chaos in the same city where the convention is being held this year, Chicago.

A brokered convention occurs when a single nominee does not emerge following the first round of delegate voting at a convention. At that point, delegates get to choose their own candidates, and party leadership will begin maneuvering to coalesce around one nominee.

Immediately on Sunday, Republicans began a full-court press to urge Biden to resign his office completely, with House Speaker Mike Johnson issuing a statement saying, "If Joe Biden is not fit to run for President, he is not fit to serve as President."

Top image: U.S. President Joe Biden delivers a nationally televised address from the Oval Office of the White House on July 14, 2024 in Washington, DC. The president was expected to expound on remarks given at a news conference earlier in the day on yesterday's shooting in Butler, Pennsylvania, in which former U.S. President Donald Trump was injured at a campaign rally. (Photo by Erin Schaff-Pool/Getty Images)

This post has been updated to include Biden's endorsement of Harris, and the statement from House Speaker Mike Johnson.