Ed Rendell, the former Pennsylvania governor and a Biden fund-raiser, acknowledged he had heard the anxieties. “They’re worried when they see only $9 million in the bank, because donors have a tendency to believe the person with the most amount of money wins,” said Mr. Rendell, who added that he does not share that view.
Mr. Schultz, the Biden campaign manager, said in an interview on Friday that Mr. Biden was facing a financial situation unlike any other Democrat: He is taking incoming fire from both the White House and primary opponents on a daily basis, and needs to play both offense and defense within the limits of $2,800 maximum donations.
“We can’t both do a general election and primary. And no one can,” Mr. Schultz said. Of his rivals who have denounced the super PAC reversal, he added, “If they were being attacked with $10 million-plus of outside money in a general election sense, I would love to see what they would do.”
Mr. Biden’s allies are not only concerned about his fund-raising: There’s also the spending. Mr. Biden raised $15.7 million in the third quarter, but he spent $2 million more than that. Among his biggest expenses was more than $920,000 on chartered jets.
Terry McAuliffe, the former governor of Virginia and a prolific fund-raiser, said that donors were “furious” about the jet spending and called the campaign’s overall money situation “very alarming.” Mr. McAuliffe’s wife recently invited donors to attend a fund-raiser for Mr. Biden at their home in early November.
Mr. Schultz, when asked about the chartered travel, said that “whatever maximizes Joe Biden and voter interaction, the greater chance we have to win.” The campaign said Mr. Biden had flown commercial but declined to indicate when his last such flight was.
The pressure over money is bound to intensify as the leading Democratic campaigns compete in the early voting states and the extraordinarily expensive media markets of Super Tuesday states like California. Ms. Warren, currently Mr. Biden’s top rival, has already reserved $2.3 million more in television ads in the early voting states than he has, according to Advertising Analytics, a media-tracking firm. In the last 30 days, she spent twice as much as Mr. Biden on Facebook ads, while Mr. Buttigieg spent more than three times as much as Mr. Biden, who has begun buying more online ads after he sharply scaled back his digital spending over the summer.