Democratic support has quickly coalesced around Vice President Kamala Harris after President Joe Biden's withdrawal from the 2024 race.

In the days since the president withdrew and backed his running mate for the top of the ticket, Harris has received an unprecedented flood of donations and backing from most party leaders, rank-and-file members and even a slate of Democrats floated as could-be Biden replacements.

On Monday night, Harris secured commitments from enough delegates to become the presumptive nominee if they all honor their commitment when voting, according to ABC News reporting.

But her formal nomination, the Democratic National Committee says, will still come as part of its previously announced plan to run a "virtual roll call" that will formally determine the Democratic nominee for president.

A DNC memo obtained by ABC News, along with a press briefing from party leadership on Monday night, provided additional details on how this virtual nomination -- ahead of the in-person convention starting Aug. 19 -- will move forward. Virtual voting could start as soon as Aug. 1 and the DNC hopes to have it "wrapped up" by Aug. 7.

How does nominating a presidential candidate normally work for Democratic candidates?

When voters cast ballots for their preferred candidate in a Democratic presidential primary, they are not actually voting directly for the candidate -- but for pledged delegates, who are individuals who have promised to support a candidate at a later party convention. A candidate nets delegates both based on the percentage of the vote the candidate gets statewide and by congressional district (in most states; some states use different divisions).

Those Democratic delegates are not formally bound to the candidate and are able to change their vote without penalty, but are pledged to follow the will of the people who elected them and are meant to reflect the will of the primary voters. The delegates formally vote for the presidential nominee at the Democratic National Convention in a roll call vote. There are nearly 4,000 pledged delegates this cycle.

Automatic delegates -- also known as superdelegates -- are not pledged, but only vote if no candidate gets a majority of the delegates in a first round of voting at the convention. There are more than 700 automatic delegates this cycle. This type of delegate is usually composed of local party leaders.

Why are Democrats holding a virtual roll call in the first place? And what changed when Biden left the race?

The DNC announced in May -- before Biden's decision to step away from the presidential race -- that it would hold a virtual roll call vote ahead of the convention.

This is because in April, Ohio's secretary of state alerted Democrats that the state's ballot certification deadline would come before the party's convention in August, meaning Biden wouldn't be the official nominee by their cutoff and thus was ineligible. The Ohio legislature later rectified the issue, passing legislation that extended their deadline and led to Biden's qualification.

Still, the DNC has argued that GOP-controlled Ohio leaders are acting in bad faith and that Biden's qualification is not assured, and that they want to avoid any legal challenges. The office of the Ohio Secretary of State has disputed this and said there would be no issue.

The virtual roll call faced increased scrutiny in recent weeks as Democratic voters called on Biden to withdraw. They argued that Biden would be confirmed as the official nominee without any real opportunity for opposition when delegates are in-person together in Chicago on the convention floor.

When Biden left the race, his delegates -- who were never legally or formally obligated to vote for him as pledged delegates -- became completely "up for grabs" and do not transfer automatically by any means over to Harris.

Still, DNC leaders told reporters on Monday that the truncated virtual process will still "ensure" that their nominees are on the ballot in all 50 states and the District of Columbia.

The DNC has held back on formally endorsing Harris -- letting the planned process still play out. The party has also said voting will be conducted similar to how party voting was done in 2020, when the COVID-19 pandemic canceled the planned in-person convention.

Technically, other candidates can still run in the virtual roll call. They must meet the party and legal qualifications to be president, file their candidacy formally with the DNC and secure the signatures of supporting delegates before the nomination vote. They also must be Democrats, not registered as independents or with another party.

Automatic delegates will not vote in any first round of voting in the virtual roll call, a DNC official said Monday.

Does Harris need to announce her vice presidential pick before the roll call?

According to the DNC, technically, no. During a Monday briefing, a DNC official indicated that candidates do not need to have selected a vice presidential pick by Aug. 7, and that the DNC is leaving that timeframe (and any concerns with ballot access in states that need a running mate) up to the candidate -- although they give the candidate the option to have running mates selected on that timeline. The official framed that as preserving how the candidate in every cycle have their own timeline to make the pick.

DNC Chair Jamie Harrison suggested Tuesday during an appearance on MSNBC that while the party has built into their working nomination proposal some flexibility surrounding vice presidential selection, the process should be "wrapped up" by Aug. 7 in order to guarantee getting the candidate on the ballot in all 50 states.

"Well, we have built this system in terms of the nomination process so that our nominee of the party has some opportunity to go through a vetting process for their VPs ... But in order to be on the ballot in all 50 states, we have to have all of this wrapped up by Aug. 7," he said.

What does it mean for Harris to have 'secured commitments' from more than enough delegates? Can they still change their minds?

As of Tuesday morning, according to ABC News reporting, Harris has secured non-binding commitments from more than 2,300 delegates -- a total that's well more than the 1,975 delegates needed to clinch the nomination.

That came because many state parties -- including groups with large delegations such as California and New York -- announced Monday, the day after Harris announced she was running, that all of their delegates would commit to supporting her. Put more simply, more than enough delegates have said they'll vote for Harris during the roll call to put her over the threshold.

"When I announced my campaign for President, I said I intended to go out and earn this nomination. Tonight, I am proud to have secured the broad support needed to become our party's nominee … I look forward to formally accepting the nomination soon," Harris said in a statement Monday night.

Delegates are not required -- legally or otherwise -- to stick to those commitments and are allowed to change their minds, which is similar to how the rules for regular nominating process would have played out.