A longtime Democratic donor said it’s “wishful thinking” that Joe Biden will quit the presidential race despite an “appalling” CNN appearance on Thursday — and insisted the commander-in-chief could still bounce back.

“Any notion that Biden is going to step aside now is wishful thinking,” Wall Street veteran Charles Myers, also a top bundler for the 2024 campaign, told The Post.

“I thought the performance was appalling but not catastrophic, and there is more than enough time to turn it around,” Myers added.

Myers, chairman of investment advisory firm Signum Global, voiced his optimism despite Biden’s stumbling and mumbling his way through Thursday’s televised debate against Donald Trump, igniting fresh concern over the 81-year-old’s cognitive faculties.

Myers also dismissed the idea that California Gov. Gavin Newsom or Michigan Governor Gretchen Whitmer could be parachuted in to face off against Donald Trump.

Myers stressed that there is “no mechanism” in the Democratic Party’s internal rules to topple Biden as their would-be presidential candidate.

“The Plan B is Kamala,” the major Biden fundraiser told the Post, referring to the vice president, who is less popular in the polls than Biden.

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But Myers also said Biden could have to stand down if Trump steals a march on him in the six key presidential battlegrounds: Arizona, Georgia, Michigan, Nevada, Pennsylvania and Wisconsin.

“I’m watching the polls closely in the swing states,” the ex-Evercore executive said. “If Trump pulls ahead by 8-9 points in the swing states over the next 3-4 weeks then there will be people legitimately asking him to step aside.”

Some Democratic operatives have questioned whether Barack Obama’s vice president can stay at the top of the ticket.

David Axelrod, a top strategist for Obama, told CNN: “There are gonna be discussions on if he should continue.”

“There is no way to spin this. His performance was disqualifying,” a top Democratic fundraiser who spoke on condition of anonymity was quoted as saying after the debate.

“I expect fundraising to dry up. Money follows enthusiasm,” the source told Reuters. “How can anyone with a straight face say ‘Donate to elect Joe.’”

Biden’s campaign and pro-Biden groups have managed to rake in as much as $389 million for this year’s White House race.

If he refuses to pull out, then Democratic National Convention delegates would need to stage a revolt at the event in Chicago in August.

The rules state: “Delegates elected to the national convention pledged to a presidential candidate shall in all good conscience reflect the sentiments of those who elected them.”

The number of delegates needed is 1,968 and Mr Biden has already gathered 3,894 because he has run virtually unopposed, despite concerns about his health.

Biden appeared to lose his train of thought on several occasions on Thursday, drifting between subjects and allowing his voice to trail off before he could complete his answers.

But he tried to dismiss calls for him to step aside with a more energetic performance at a rally in North Carolina on Friday.

“I know I am not a young man,” he told supporters.