Biden has endorsed Harris. What happens next?

President Joe Biden surprised American voters on Sunday by announcing he was withdrawing from the presidential race after resisting calls to step down.

Although he will serve out the remainder of his term as president, he has endorsed Vice President Kamala Harris to succeed him as the Democratic nominee.

With just a month left before the Democratic National Convention, the decision pushes Democrats into uncharted territory.

Here’s a guide to what might happen next.

The last time a sitting U.S. president gave up his bid for re-election was Lyndon Baines Johnson in 1968.

President Biden has won 3,896 pledged delegates – far more than needed to secure the party’s nomination.

While Mr. Biden’s endorsement made Ms. Harris the most likely nominee, after he released delegates they no longer committed to supporting the candidate.

Ultimately it will be up to them to vote for the person of their choice.

The Democratic National Convention is scheduled to begin on August 19.

If Democrats don’t unite behind a new candidate, it could set the stage for a public convention for the first time since 1968.

This means that delegates are free to decide who to vote for among multiple candidates, if one arises.

Candidates need the signatures of at least 300 delegates (no more than 50 delegates from a state) for their names to appear on the ballot.

The first round of voting will take place among 3,900 pledged delegates, including voters considered loyal to the Democratic Party.

If no candidate receives a majority of votes after the first round, further rounds of voting will take place. These rounds of voting will include superdelegates — party leaders and elected officials — who all vote until a nominee is chosen.

To win the party’s nomination, a candidate needs 1,976 delegates.

In recent weeks, as calls have grown for Biden to drop out of the race, a number of potential replacements have emerged.

Gretchen Whitmer, the Democratic governor of Michigan, has been nominated as a candidate, but she said she would not consider running if Biden were to step down. Minutes after Biden made the announcement on Sunday, she said she would do whatever it takes to “elect Democrats and stop Donald Trump.”

Other options include California Gov. Gavin Newsom, Transportation Secretary Pete Buttigieg and Pennsylvania Gov. Josh Shapiro.

Some of these candidates may be considered for vice president if Ms. Harris ultimately wins the nomination.