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President Joe Biden’s decision not to run for reelection creates a unique situation for Democrats and Democratic voters in which the person who won party primaries is no longer the party’s candidate.

Biden won the pledge of nearly every delegate during the primary process, when voters chose him as their nominee. Under party rules, now those delegates are free to choose someone else.

That someone is expected to be Vice President Kamala Harris, who first got Biden’s endorsement on Sunday, and around whom other Democrats have rallied. A majority of Democrats to the Democratic National Convention have now endorsed Harris.

As we first wrote back in February, these individual delegates will now select the party’s nominee on the convention floor (or, likely, during a virtual roll call before the convention gets underway).

These delegates aren’t just pledged to vote for Biden; they’re also approved by his campaign. So it will largely be Biden backers who will be picking his replacement.

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Biden’s delegates can now back Harris

Now that Biden is no longer a candidate, his delegates are free to vote for whomever they’d like. He doesn’t need to formally “release” his delegates. But Biden, in a post on X announcing he was leaving the race, also endorsed Harris. Democrats have overwhelmingly followed his lead.

As of Monday evening, Harris had the support of enough Democratic delegates to win the party’s nomination, according to CNN’s delegate estimate, although the endorsements are not binding.

But all of the Democrats – governors and senators – who have been mentioned as likely future presidential candidates are among those who have endorsed Harris.

When will this be official?

Rather than engage in a divisive fight, the party is rallying around Biden’s No. 2, and they’re looking to do it quickly.

The Democratic Party is moving forward with a process that will determine the party’s presidential nominee by August 7, weeks before the convention gets underway, party officials said Monday night.

Could other candidates still get into the race?

According to DNC officials and a document obtained by CNN, candidates will need to declare their interest in becoming the Democratic Party’s nominee for president by filing a formal declaration of candidacy, meeting party and legal qualifications to be president, and gathering at least 300 delegate signatures from convention delegates, with no more than 50 from a single state.

The window of time for candidates to declare their interest will be short, one DNC official said, and would end by this week.

Under the proposal, the DNC will share with delegates a candidate directory, which will include names and contact information for candidates to allow delegates to opt into information from campaigns.

How does the nomination vote work?

While the DNC intends to have a Democratic nominee chosen by August 7, exactly when virtual voting would begin has yet to be determined and would depend on factors like how many candidates are ultimately able to obtain support from the necessary 300 delegates.

A date for the start of the virtual voting process, therefore, has not yet been set, but it could be as early as August 1.

To win the nomination, a candidate will have to have the support of a majority of pledged delegates to the convention – 1,976 out of 3,949 pledged delegates, party officials said.

While all delegates will receive ballots, votes cast by superdelegates – roughly 750 senior Democrats who serve as delegates by virtue of their position – will be counted on the first ballot only if one candidate has the support of enough pledged delegates to make up a majority of the full convention. That could be determined either by a candidate winning enough votes during remote balloting, or by gathering that many signatures.

The number of superdelegates can also shift if one dies or resigns. Rep. Sheila Jackson Lee, the longtime Texas congresswoman, died on July 19, reducing the number of superdelegates by one, bringing the official number to 746.

The convention rules committee will vote Wednesday on the proposed rules, a Democratic official said.

How does the candidate for vice president get determined?

Harris will select a running mate. In practice, there is typically not a roll call vote for vice president, with the presidential nominee’s choice for the position typically nominated by acclamation.

Party officials were less specific Monday about the timing of the vice presidential nomination, saying that while they would give the future nominee the ability to finalize the choice by August 7, the exact schedule would be up to the candidate.

In 2020, when the party used a similar virtual roll call during the Covid-19 pandemic, the Democratic process functionally allowed the winning candidate for president (Biden) to nominate the vice presidential candidate (Harris) without the need for an additional roll call.

Will the Democratic nominee have any trouble getting on the ballot?

House Speaker Mike Johnson has complained about this process and said Republicans might file lawsuits in certain states. He has not gotten into specifics. But after the convention nominates a candidate, many election law experts say they won’t have much or any trouble getting on all 51 presidential ballots.

Unlike independent candidates, the Democratic and Republican nominees for president don’t need to gather signatures to appear on the ballot.

Instead, the major parties, by virtue of their popularity, enjoy automatic ballot access in every state. While the process varies by state, the parties typically submit their nominees’ names (and the names of candidates for presidential elector) to the state.

Biden hasn’t been officially nominated and the party hasn’t submitted his name to state officials. So the new nominee wouldn’t be, in an official sense, replacing Biden. Whoever the delegates select will be the Democratic nominee and they shouldn’t have an issue taking the Democratic ballot line.

However, that doesn’t mean that there wouldn’t be the possibility of litigation, even if it would be unlikely to succeed.

This story has been updated following Biden’s decision to drop out of the race and with additional details from the Democratic National Committee.

CNN’s MJ Lee contributed to this report.