What Happens Next if Biden Steps Down From Campaign

US President Joe Biden at a news conference during the NATO Summit in Washington, DC, US, on Thursday, July 11, 2024. Credit - Graeme Sloan–Bloomberg via Getty Images

As a growing number of congressional Democrats call on President Joe Biden to withdraw from the 2024 presidential election over concerns regarding his electability, some in the party have started grappling over the possibility of a nominee replacement.

But the decision to step aside rests entirely with Biden, and the President has said that he is committed to staying in the race. “I’m determined on running,” Biden told reporters at a news conference on Thursday night, suggesting that he would drop out only if polls showed there was “no way” for him to win. “They’re not saying that. No poll says that,” he added.

At the moment, 19 Democratic members of Congress have called on Biden to withdraw from the election, making up just over 7% of the caucus. Many have expressed concerns that a Biden-led ticket could threaten vulnerable down-ballot candidates, while others have questioned his mental acuity following his poor debate performance.

So what does it look like if Biden ultimately decides to drop out of the race? Here’s what historians say would happen in the event Biden steps down.

Biden dropping out so late would be ‘unprecedented’

If Biden were to bow out of the presidential race ahead of the election in four months, he would be the first to do so this late in the campaign cycle, according to multiple historians. But it wouldn’t be the first time an incumbent president decided to withdraw their candidacy or not seek re-election.

Matt Dallek, a political historian at George Washington University, says that former Presidents Harry Truman (1952) and Lyndon B. Johnson (1968) each decided to withdraw their re-election campaigns in March of their election years despite being eligible to run for a second term. “It's not unprecedented for an incumbent president to decide not to run for reelection,” Dallek says, “but what would be unprecedented and what makes the Biden situation unique is that it is so late in the campaign.”

He adds that no candidate has ever withdrawn after securing enough delegates in the presidential primaries to be the nominee. (Biden clinched the Democratic nomination in March after winning more than 3,800 delegates).

Kevin Boyle, an American history professor at Northwestern University, says that the closest parallel to a presidential candidate dropping out late in their campaign was in October 2016 when the infamous Access Hollywood tape and its audio of former President Donald Trump bragging about sexual assault was made public a month before the election. “There was an awful lot of talk inside the Republican Party about replacing Trump as the nominee at an even later date than we’re talking about now,” Boyle says. Many assumed the scandal would force Trump to step aside, but he stayed in the race and won.

Read More: As Biden’s Name Mix-Ups Draw Attention, Supporters Point to Trump’s Similar Gaffes

The complex process to replace Biden as a nominee 

Replacing a nominee close to Election Day would entail a complex process, but the Democratic National Committee (DNC) does have rules in place for such a scenario.

Historians say that if Biden ends his campaign ahead of the Aug. 19 Democratic convention, his pledged delegates would be free to back other candidates and Democrats would choose a nominee at the event. However, the process could get messy if Biden were to not endorse a replacement candidate, which is what happened in 1968 after Johnson dropped out of the race, Boyle says.

Dallek adds that “if Biden were not to endorse his Vice President, then there would be a mini campaign to recruit and win the support of a majority of the delegates.” During that mini campaign, the winning candidate would need to secure the support of a majority of delegates to capture the nomination. Vice President Kamala Harris, Biden’s running mate, would enter the nomination fight with an early advantage but other potential candidates may have an inside track to a large number of delegates from their home states.

Julian Zelizer, a political historian at Princeton University, warns that open conventions with several candidates competing for the nomination can sometimes be grueling and have multiple roll call votes. During the 1924 Democratic National Convention, it took a record 103 ballots before John W. Davis emerged as the presidential nominee.

If Biden were to withdraw from the election after being nominated at the Aug. 19 Democratic convention, the DNC would need to select a new nominee “by majority vote in a special session called by the chair,” according to the National Election Task Force. That scenario occurred in 1972 when Thomas Eagleton withdrew as the vice presidential nominee, leading the DNC to select Sargent Shriver as his replacement on the ticket.

How Biden could secure Kamala Harris the nomination

If Biden were to withdraw from the race, political historians say the most likely scenario is that he would endorse Harris. Biden has persisted that he is not planning to drop out, but he did praise his Vice President on Thursday for her work on abortion rights and her time in the Senate.

“Look, I wouldn’t have picked Vice President Trump [Harris] to be vice president [if I didn’t] think she was not qualified to be president,” Biden said at his press conference on Thursday. Several congressional Democrats have said they would endorse her if Biden decided to exit the race in large part because she would inherit Biden’s campaign cash—around $91 million as of May 30—given that her name is already on the current presidential ticket.

“I don't care how talented you are—you can’t put a campaign together instantly that's going to win a national presidential race,” Rep. Glenn Ivey, a Maryland Democrat who would back Harris over outside candidates as the nominee, tells TIME. “It's not realistic.”

Zelizer says fundraising “would be more complicated with the other candidates” since almost all of the money in the Biden-Harris campaign account would have to be refunded to donors if the nominee was another candidate.

Did the Founding Fathers plan for this moment in the Constitution?

Historians say the Founding Fathers never anticipated the modern complexities of political campaigns, including the potential need to replace a presidential nominee close to Election Day. They also never anticipated the emergence of political parties as dominant entities in American politics, nor did they foresee the intricate systems of primaries, conventions, and delegate selection processes that shape modern presidential nominations.

While the Constitution requires a president to be at least 35 years old, there is no maximum age for the job. The Founders did, however, anticipate the need for a line of succession and included a provision in the Constitution for replacing the President if they were unable to fulfill their duties. “It’s worth remembering that life expectancy in the United States was way lower back then,” Boyle says.

“I don’t think this exact moment was in the purview of the Founders,” Dallek says. “We're living in a dramatically different world from the one they did.”

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Write to Nik Popli at nik.popli@time.com.