What happens next if Biden drops out of the presidential race

• President Joe Biden is under mounting pressure to withdraw his reelection bid in the wake of his damaging debate against Donald Trump.
• The campaign crisis has put a spotlight on Vice President Kamala Harris, who many pundits and experts view as the likeliest choice to replace him.
• Biden recently floated the possibility that a "medical condition" could force him to rethink his decision to stay in the race.

President Joe Biden is under siege from within his own party, as more Democrats — in private and in public — urge him to end his reelection bid in the wake of his damaging debate against Donald Trump.

Biden's efforts to shore up confidence in his candidacy have failed to close the growing rift between him and his party. And while he has so far roundly rejected the calls to step aside, Biden said Tuesday that should a "medical condition" emerge, it could force him to rethink his decision to stay in the race.

On Wednesday, Biden, 81, tested positive for Covid-19. His doctors say his symptoms are mild.

Realistically, the only way to replace Biden at the top of the Democratic ticket at this stage in the campaign cycle is if he agrees to drop out voluntarily, or if he dies or suffers a "disability."

After breezing through the primary virtually unopposed, Biden has won almost all of his party's 4,000-plus delegates, who are selected in large part because of their loyalty and support for their chosen candidate. Those delegates are set to vote for their presidential nominee in a virtual roll call in early August, before the Democratic National Convention.

If Biden ends his campaign before voting begins, the pledged delegates could cast their ballots for a new candidate. According to the DNC rules, If no candidate won a majority