When aides to President Joe Biden heard in recent days that George Clooney, as close a figure as there is in Hollywood to royalty, planned to publicly break with Biden in an essay that cast doubt on his reelection chances, panic set in from Wilmington, Delaware, to Beverly Hills, California.

Could Clooney be persuaded not to publish it?

Movie mogul Jeffrey Katzenberg sought to intervene. Katzenberg, who moonlights as a top Biden official and has worked with Clooney on philanthropy for decades, reached out to him to see if there was an off-ramp, according to three people familiar with the matter. There was not. Clooney published his essay in The New York Times, and the president’s relationship with Hollywood was torn asunder.

The fallout from the Clooney essay has ricocheted across the worlds of politics and entertainment — and onto Katzenberg himself. It has turned Hollywood, America’s drama capital, into ground zero for the impasse between the Biden campaign and the major donors who increasingly do not want it to proceed.

“This is a town that pays attention to box office, and the numbers do not look encouraging right now,” said Billy Ray, the screenwriter behind “The Hunger Games” and other films who has worked with Democratic candidates on messaging. “I do think they’re going to have a challenge raising more money.”

The Biden large-donor scene, where Katzenberg is treated as royalty himself, has been devastated since Biden’s debate performance two weeks ago. Several fundraising events are in jeopardy, and scores of donors have informed the campaign they will not continue to give if Biden remains in the race. The campaign has pointed to its recent low-dollar fundraising success.

Still, top Biden campaign officials are already bracing themselves for a July fundraising report — which will not become public until mid-August — that is expected to show the campaign’s finances falling off a cliff. Biden is coincidentally scheduled to travel to Southern California for a fundraiser this month that is likely to be attended by some top Hollywood players.

And Hollywood has disproportionately voiced some of the earliest and most aggressive calls for Biden to drop out. Ari Emanuel, the power agent who is the brother of Rahm Emanuel, the former chief of staff to President Barack Obama, said days after the debate that Biden’s insistence in staying in the race was a “self-aggrandizing delusion on a Trumpian scale.”

Reed Hastings, the co-founder of Netflix, was one of the first Democratic megadonors to explicitly call for a new nominee, a case he is continuing to make privately to other media and technology executives.

But the most politically damaging blow came from a late-breaking apostate: Clooney, who just weeks earlier had spent time with Biden and helped deliver $28 million to his campaign at a Los Angeles fundraiser.

“Clooney is more than just a celebrity,” said Brian Goldsmith, a Democratic fundraiser and media consultant in Los Angeles. “He’s in the Tom Hanks and Steven Spielberg category of a huge cultural figure and serious political powerhouse. His op-ed broke through to pop culture — to influencers and People magazine — and therefore to a much wider audience than folks following news on Capitol Hill.”

The fundraiser last month — which included top entertainment executives, donors and Julia Roberts — was meant as a show of force but has now taken on a darker, historical significance as the night when Biden lost Clooney.

The actor wrote in his Times essay that he learned that evening that Biden was no longer the candidate he saw up close in 2016 or even in 2020. Like many Biden supporters, he hoped the president, his “hero,” would conclude on his own that it was time to step aside, according to a person who has spoken with Clooney in recent weeks.

Onstage at the fundraiser beside Obama and Jimmy Kimmel, Biden laughed along, cracked a joke or two and slammed the Supreme Court. The audience ate it up.

At the end, Biden soaked up the applause — perhaps a beat too long. Obama gently took his hand and led him away. A video of the moment went viral. Was the 44th president being impatient, or was the 46th freezing up?

“There were a lot of fans in the crowd, like me,” said Roger Wolfson, a Hollywood writer. “But there was also nervousness. A lot of dry grass — and while the debate could have watered the grass, it seems to have served more like a match.”

One Democrat who worked with Biden in a previous stage of his career and sat near the front during the fundraiser described being “shocked” at the president’s condition.

Damon Lindelof, a Hollywood producer, said the fundraiser had been an “awakening” for him, giving him the “ability to hear all the contrarian voices I had been shouting down for the past year.” After the debate, Lindelof called on donors to close their wallets to all Democratic campaigns until Biden stepped down.

Biden had flown to Los Angeles directly from Italy, which his aides said spoke to his stamina. But in videos of the public portion of the event, he appeared tired at times, sometimes stumbling over his words.

Some attendees who spent time with Biden that night privately defended him.

Carol L. Hamilton, a Los Angeles lawyer who serves on Biden’s National Finance Committee, sat in the third row at the Hollywood event. She said, “I was a little surprised by Clooney’s opinion piece, because he clearly had a different experience than I did.”

She and her husband spent time with Biden at a more exclusive reception before the onstage presentation, she said, and had a conversation with Biden about a missile testing moratorium she worked on at the United Nations in 2022 — “a pretty sophisticated area that he gets,” she said.

Biden’s allies have also responded by going after Clooney, arguing that he did not spend enough time with Biden at the event to assess his strength — just about 10 minutes, according to a campaign staff member who was present.

Clooney and Roberts had arrived at the event together around 4:30 p.m., according to two people who spent time with them that day and insisted on anonymity because of the sensitive situation. Over the next two hours, they spent time greeting donors, the two people said. They also posed for pictures with Biden before introducing him onstage around 7 p.m., another attendee said.

At the center of the Hollywood drama is not only Clooney but also Katzenberg, a ringmaster of both Biden’s fundraiser at Radio City Music Hall in New York City and the Los Angeles event.

Last year, the wiry and relentless Katzenberg was chosen as the co-chair of Biden’s entire campaign and quickly took a public role. He led a news conference before the Republican caucuses in Iowa. Paparazzi took photos of him dining with Jill and Hunter Biden at Giorgio Baldi, the Santa Monica celebrity cantina.

Katzenberg is now taking his commensurate lumps, particularly because contributors feel he helped disabuse donors of concerns about Biden’s physical state.

Over the past year and a half, Katzenberg choreographed a series of lunches at the White House where skeptical donors could spend time with Biden and see that there was nothing to fear about his stamina or mental command. Several gave maximum contributions to Biden’s victory fund afterward, including tech founder Mark Pincus. Pincus attended alongside his political collaborator Reid Hoffman, now perhaps Biden’s strongest donor ally.

But on Thursday, Pincus said a new nominee was needed because Biden would never “get around this age competency issue.”

Despite many donors’ unhappiness with Katzenberg, few would go on the record out of fear of his power.

In the view of Katzenberg’s allies, however, these wealthy donors made their own decisions to contribute, and he should not be held responsible for Biden’s weaknesses. Katzenberg has been almost entirely publicly silent since the debate. A representative of his declined to comment.

At this critical time, Katzenberg has spent the week in Sun Valley, the Hollywood-heavy getaway in Idaho, where Biden’s fate is the topic of feverish conversations.

Before arriving there, he told one associate that he planned to relay a message of calm to his fellow moguls, the person recalled. He was adamant that he was still with Biden and indicated he had no regrets about how things were going, the person said.

The New York Times News Service