Vice President Kamala Harris' allies are privately discussing what her candidacy would look like if President Joe Biden dropped out of the race for the White House and how they could help her, following Biden's disastrous debate performance Thursday, according to people familiar with the matter.

These conversations have been held over phone calls and text messages between some people who raised money for the vice president during her failed 2020 Democratic primary campaign against Biden and other contenders, said the people, who were granted anonymity in order to speak freely about private conversations.

Key issues include whether Harris would control the massive Biden-Harris campaign war chest managed by Biden's team if the president were to drop out of the race.

Harris has emerged as an early favorite to replace the president at the top of the ticket, but this does not guarantee that the Democratic National Convention in Chicago will not feature more contenders and a potentially messy battle for the nomination.

Harris would likely have the keys to most of the money, according to Biden campaign manager Julie Chavez Rodriguez, who acknowledged the rules during a recent call with party donors. Biden's campaign began June with $91 million in cash on hand, according to Federal Election Commission records. The entire political operation, which includes Biden's joint fundraising committees, entered July with $240 million on hand, according to the campaign.

There's also discussion among Harris confidants about the need to begin scheduling meetings for the vice president with some of the biggest donors in the Democratic Party if Biden drops out, these people said.

Harris' allies have been pushing other donors and party officials to reconsider the potential advantages the vice president's policy portfolio could bring to a Democratic campaign platform: Her focus on reproductive rights, her outreach to Black voters and marginalized communities and her remarks in February in Germany, when she emphasized the strength of U.S. support for Ukraine in its fight against Russian invasion, according to a person familiar with the engagement.

Some of Harris' past fundraisers are also texting one another an old one-minute video that features the vice president taking on former President Donald Trump's appointees while she was a U.S. senator, according to a person with direct knowledge of the matter. It shows clips of Harris facing off with the likes of former Attorneys General Bill Barr and Jeff Sessions and then Supreme Court nominee Brett Kavanaugh.

The video also underscores a key message, they say: Harris' willingness to confront Trump's allies shows that she has what it takes to go face to face against the former president. "Taking on Trump one on one, Kamala will use her backbone, her values, and her experience as a prosecutor to expose Trump," a voiceover for the advertisement says.

The video was produced for a political action committee called "People Standing Strong," which was never fully activated because Harris dropped out in 2019 shortly after it was created. The PAC reportedly reserved nearly $300,000 worth of advertising across the key state of Iowa but the ads were not aired because Harris dropped out before the state's caucus.

A White House spokeswoman for Harris and Biden campaign representatives did not respond to requests for comment.

Any discussions of what Harris might need to win a convention fight for the nomination was unthinkable for Democrats before Thursday's debate, when Biden struggled to make the case for his reelection and failed to push back on Trump.

Biden's poor debate performance greatly changed the mood among donors, with many privately discussing the need for the president to step aside in order to give the party the best chance of beating Trump in November.

The donors sending around the video, for instance, are "all just confused, scared and sad" since the debate, said a longtime strategist close to many of the top fundraisers in California. "They're desperate to beat Trump."

Dmitri Mehlhorn, a longtime advisor to Democratic donors including tech investor Reid Hoffman, said in an email Wednesday to allies that was shared with CNBC that although he continues to support Biden, in his view Harris would be a solid alternative to take on and potentially defeat Trump.

"To be clear, Vice President Harris is a badass. A ticket with her at the top, combined with someone who balances her brand weaknesses (examples range from Mark Kelly to Andy Beshear to Roy Cooper to Josh Shapiro and many others), would absolutely be competitive with the criminally insane convicted felon the other side is committed to nominating," wrote Mehlhorn.  "We would lose Joe's superpower brand, but we would gain other benefits and would still be competitive."

Biden's team has said the president is not dropping out of the race. Meanwhile, Harris, to all appearances, has remained loyal and is scheduled to have lunch with the president at the White House on Wednesday.

Despite his team's public pledge that he won't drop out, The New York Times and CNN reported Wednesday that Biden has signaled privately to an ally he may not be able to salvage his candidacy.

White House spokesman Andrew Bates vehemently denied the story in a social media post. CNBC and NBC News have not independently confirmed the conversation.

Harris defended the president's debate performance to a group of her past donors in San Francisco on Tuesday.

The event was at real estate executive Susan Lowenberg's home, and the crowd included Harris donors from the time when she was running for San Francisco District Attorney, according to the pool report.

"We gotta fight, and we know how to fight," Harris said to the crowd. "When we fight, we win." 

Since the debate, there's been a growing chorus of party donors, most of whom have spoken in private, and a few lawmakers who have spoken in public who question whether Biden is up to the task of being president for four more years, and if he is not, whether it's right for him to be the party's nominee in November.

Rep. Lloyd Doggett, D-Texas, on Tuesday became the first Democratic lawmaker in Congress to call on Biden to step down.

Former House Speaker Nancy Pelosi, D-Calif., and Rep. Jim Clyburn, D-S.C., both longtime Biden allies, said in interviews on MSNBC that it's fair for voters to ask about Biden's health in the wake of his debate performance.

"I think it's a legitimate question to say, 'Is this an episode or is this a condition?'" Pelosi said in the interview, noting that the question should be asked of both Biden and Trump.

The polls have had a mixed message for Biden since the debate.

A CNN poll shows that Trump is ahead of Biden by 6 percentage points nationwide, which is identical to the network's national poll in April.

But 75% of those polled say that someone else other than Biden would have a better chance of beating Trump than Biden would.

Harris' stock has also started to rise in online betting pools about who will be the Democratic nominee for president.

PredictIt, which allows people to make bets on political events, now puts the vice president in a close second to Biden.

Before the debate, PredictIt put her odds of becoming the party's nominee this year so far behind Biden that she was trailing the likes of California Gov. Gavin Newsom.