What if Joe Biden leaves the US presidential race?

WASHINGTON: After US President Joe Biden's woeful performance at the debate with former president Donald Trump on Thursday (Jun 27) night, some Democrats openly questioned whether he should be replaced as their candidate for the 2024 election.
Such a high-risk political U-turn would be unprecedented in modern American election history.
Biden indicated that he had no plans to end his campaign, telling supporters in Atlanta shortly after he left the debate stage, “Let's keep going". It would be nearly impossible for Democrats to replace him unless he chooses to step aside.
DELEGATES ARE BOUND TO BIDEN
Biden overwhelmingly won the primary votes, and the party's roughly 3,900 delegates heading to the convention in Chicago this August are beholden to him.
To designate a formal nominee, delegates from all 50 states attend their party's summer nominating convention to officially anoint a candidate based on primary voting.
If Biden exits, the delegates would have to find a replacement. That would mean bringing US politics back to the old days, when party bosses jostled to pick a nominee through deal-making in smoke-filled back rooms and endless rounds of voting.
On Mar 31, 1968 President Lyndon Johnson made the shock announcement in the middle of the Vietnam War that he would not seek reelection.
The move turned that year's convention, also in Chicago, into a political crisis with protesters in the street and left-leaning delegates angry at the pro-war stance of party-picked candidate Hubert Humphrey.
Following the debacle, states more widely embraced the primary process and conventions have become well-oiled affairs, whose outcomes have been known in advance since they are determined by the primaries.
If a candidate must step down after being officially nominated at the convention, a party's formal governing body, either the Democratic National Committee or Republican National Committee, would nominate a new candidate in an extraordinary session.
WHO MIGHT FILL IN?
Vice President Harris would almost certainly be at the top of the list, but she has had her problems after a rocky start in the job and poor polling numbers. The US Constitution dictates that the vice president becomes president if the president dies or becomes incapacitated, but it does not weigh in on an inter-party process for choosing a nominee.
In addition to the vice president, others who had endorsed Biden in 2024 while harbouring their presidential aspirations for future cycles include California Governor Gavin Newsom, Michigan Governor Gretchen Whitmer, Pennsylvania Governor Josh Shapiro, Illinois Governor JB Pritzker, and Transportation Secretary Pete Buttigieg.
Candidates would have to get signatures from 600 convention delegates to be nominated. There are expected to be some 4,672 delegates in 2024, including 3,933 pledged delegates and 739 automatic or superdelegates.
There would likely be nominating speeches and seconding speeches. Multiple candidates could be nominated before the list is whittled down.
If no one gets a majority of the delegates, then there would be a "brokered convention" in which the delegates act as free agents and negotiate with the party leadership to come up with a nominee.
Rules would be established and there would be roll call votes for the names placed into nomination.
It could take several rounds of voting for someone to get a majority and become the nominee. The last brokered convention when Democrats failed to nominate a candidate on the first ballot was in 1952.