What happens to Biden’s money if he withdraws?

President Biden is adamant that he is not dropping out of the presidential race. But if he does, there’s a reason or two that many in his party’s leadership think the next vice presidential nominee would be Kamala Harris.

There is the built-in Democratic base. There is the easier logistics. There is the history that needs to be written.

And yes, there is money.

If Democrats were to make a stunning change at the top of their ticket, what happens next would have no modern precedent — including on campaign finance. But we do know a few things:

Kamala Harris is said to have a lead of approximately $91 million.

Over the past two years, Mr. Biden and Ms. Harris have collectively raised hundreds of millions of dollars for their re-election bids. That money has been split among the Biden campaign, the Democratic National Committee, nearly every Democratic Party in the state and various joint fundraising committees that move money between all those entities.

As of June 30, all of those groups had about $240 million in cash on hand. Most of that money — the stash at the Democratic National Committee, for example — wouldn’t be affected by a change in nominee.

But the most important money is in the Biden-Harris campaign committee accounts: $91 million as of May 30. (The campaign has not disclosed how much it had as of June 30.) That money was raised by the Biden-Harris ticket and belongs to the Biden-Harris ticket. The only people that money is being tracked are, you guessed it, Mr. Biden and Ms. Harris.

So if Mr. Biden were to relinquish his role and Ms. Harris were to be officially nominated (with a new No. 2), her new ticket would have virtually no financial disruption. She would have immediate access to the $91 million or so in cash she has on hand, an important consideration given how former President Donald J. Trump and Republicans quickly outpaced Democrats in fundraising.

Whitmer, Newsom or someone else would complicate things.

What if the new nominee wasn’t Ms. Harris, but someone like Governor Gretchen Whitmer of Michigan or Governor Gavin Newsom of California?

In that case, nearly all of the $91 million in the campaign account would have to be returned to donors, a rather unlikely outcome. (One caveat: The money earmarked for the primaries, unlike the general election, can be used by anyone until the Democratic National Convention next month.)

But there’s a catch, one dictated by recent precedent. If anyone other than Ms. Harris were to take the lead, the Biden-Harris campaign could certainly transfer that $91 million to a federal super PAC, which could then spend it advertising the new Democratic ticket.

That would be suboptimal, because money held by an outside group can’t be directly managed by the campaign, and super PACs have to pay higher rates for advertising time. But the money wouldn’t be lost entirely.

There is, however, an alternative way for a new presidential candidate who is not Harris to benefit from the campaign account money, one that smart Democrats would almost certainly explore.

When Michael R. Bloomberg withdrew from the 2020 Democratic presidential primary, he had about $18 million left in his campaign account. He was eventually able to transfer all of that money directly to the Democratic National Committee.

The $18 million far exceeded the maximum contribution for individual donors. Moreover, Bloomberg’s transfer was controversial, as he was almost entirely self-financing his presidential campaign.

While federal campaigns can direct the remaining money to any group they want without limit, critics argued that Mr. Bloomberg’s transfer effectively allowed someone to skirt the contribution limits by (briefly) running for president. Campaign finance regulators cried falsely, but the Federal Electoral Commission effectively approved the measure last year.

That precedent could be instructive here. Perhaps the Democrats would try to transfer that $91 million directly to the DNC — creating a deep-pocketed party committee that could offset the fact that a brand-new candidate’s campaign would start with nearly $0.

A billionaire like JB Pritzker could be a real knight in shining armor.

If the nominee isn’t Mr. Biden or Ms. Harris, there’s one way the Democratic ticket can’t start from scratch. In that scenario, the smartest financial move for Democrats would be to turn to a billionaire who can turn that zero into, well, a big number followed by a bunch of zeros.

Take someone like Governor J.B. Pritzker of Illinois. The heir to the Hyatt hotel fortune, he spent 350 million dollars during his two campaigns for governor, and theoretically, by writing a check, he could pump far more than $91 million into a presidential campaign.

Self-funders are not subject to contribution limits. And so choosing one of them could allow a new Democratic presidential campaign to achieve some parity with Mr. Trump almost immediately.

If Democrats reopen their nomination race to a broader group of hopefuls, it would be quite remarkable to see independently wealthy candidates bragging about their wealth. But their fortunes would undoubtedly be political assets.

Small donors are an X-factor.

One of the uncertainties in all of this is how one very important type of donor – the small one – would respond to a Democratic presidential race.

If some of Biden’s opponents are to be believed, his removal from the list would create a huge frenzy, prompting donors large and small to support a campaign led by a younger Democrat, up to the individual limit of $3,300.

A new nominee would indeed be exciting for many Democrats. But it could also be quite terrifying.

Could Democrats’ digital fundraising collapse during a time of great uncertainty? What if the new nominee proves even less competitive than Mr. Biden, who, for all his flaws, has a digital fundraising operation that has been pulling in money for five years?

For Democrats, there are no easy answers. Just lots of questions.