(Bloomberg) -- Key Republicans are trying to choke off any momentum that Donald Trump can build for a third White House campaign to make room for a fresh GOP standard bearer. 

In recent days, two of the most prominent conservative donor groups, the network founded by the billionaire Charles Koch and his late brother David, as well as the anti-tax Club For Growth, indicated their desire for a nominee other than Trump in 2024. Collectively, that amounts to millions of campaign dollars essentially being up for grabs. 

The goal of these groups and operatives is to stop Trump before the Republican field gets too crowded, allowing him to galvanize the roughly 30% of GOP voters who he has said would support him even if he shot someone in the middle of Fifth Avenue.

He eked out his 2016 primary victory by relying on that base of support while viciously attacking opponents with nicknames and jabs on Twitter —- and Republicans worry he could replicate that for 2024. 

Yet he’s now at his weakest moment politically since the period after a mob of his supporters stormed the US Capitol on Jan. 6, 2021. The 2022 midterm elections, which Republicans predicted would be a triumph for their party, turned into a stinging disappointment, and some blame Trump for elevating acolytes in primaries who fared poorly in statewide contests, and for continuing to repeat false claims about his 2020 loss. 

Americans for Prosperity, backed by the organization started by the Koch brothers, said in a memo that “the American people have shown that they’re ready to move on” to a new leader in 2024. A similar sentiment was expressed by the Club For Growth. 

Steven Cheung, a spokesman for Trump, fired back at Club For Growth, saying that it “endorsed 24 candidates during the 2022 midterm election and lost 25% of them. On the other hand, President Trump had 233 wins out of 253 races.”

The public pronouncements send signals to other donors to remain neutral and might well embolden Trump’s potential challengers. Trump is the only declared candidate, though former South Carolina Governor Nikki Haley is expected to announce a run on Feb. 15. 

Mega-donor Miriam Adelson dined with Trump at his Florida Mar-a-Lago estate in recent months to let him know she intended to sit out the GOP primaries, according to two people briefed on their meeting. That is among the biggest losses for Trump. In 2020, she and her late husband, Sheldon Adelson, donated $90 million to his political action committee.

Trump has deepened attacks against Florida Governor Ron DeSantis in recent days, coinciding with donors’ calls for a new Republican champion. It’s a sign that Trump expects much of the party to coalesce around DeSantis, his closest challenger in polls. 

A Monmouth University Poll released Thursday showed DeSantis out-polling Trump 53% to 40% in a hypothetical head-to-head match-up. Both men garnered 33% when Republican and GOP-leaning US voters were asked who they want to see as the party’s nominee. 

John Catsimatidis, a New York billionaire, said he is withholding his backing for any candidate in what he thinks could be a very crowded primary contest with a dozen or more candidates. The real estate and grocery store magnate was a vocal Trump supporter in 2020 giving hundreds of thousands of dollars to the president’s Victory committee.

“I have not picked a candidate yet,” he said in an interview. “Let’s see how things sort themselves out.”

Already, prominent donors such as Ken Griffin of Citadel and Stephen Schwarzman of Blackstone Group Inc. have indicated they won’t support Trump again financially. 

Some deep-pocketed GOP benefactors, including the Koch family, have withheld support from Trump since 2016. But he is now facing a growing group of influential and wealthy donors who supported him in 2020 and are publicly breaking with him. Among the defectors are cosmetics heir Ronald Lauder and Interactive Brokers Group Inc. founder Thomas Peterffy. 

Hedge fund manager Robert Mercer and his daughter Rebekah Mercer have also said they won’t finance Trump’s 2024 bid.

The public, too, is clamoring for new leaders. Forty-nine percent of Republicans and Republican-leaning independents said in a Washington Post-ABC News poll that they would prefer another candidate instead of Trump, while only 22% of US adults surveyed by the Associated Press and NORC Center for Public Affairs Research said President Joe Biden should run again.

“People are past the performance art. They want to hear substance from the candidates,” said David Urban, a longtime Republican lobbyist who helped Trump win Pennsylvania in the 2016 race. “Can you win? If people think Trump can win, they will vote for him.” 

The former president has built a sophisticated online fundraising operation that is largely immune to the influence of the GOP’s network of bundlers, donors and power brokers. Since becoming a candidate in 2015, he’s raised $1.2 billion from contributors who, in aggregate, have donated $200 or less, in part by hawking a wide range of branded merchandise including his signature red “Make America Great Again” caps.

Despite not being on any ballot, he raised more than $180 million in the 2022 election cycle, causing grumbling among Republicans that he was diverting money needed by House and Senate candidates in tight races. Though he’s raised less than $10 million since becoming a candidate, a super-PAC set up by allies to aid his primary run ended the year with $54 million.

Big-name donors and well-organized political groups turning away from him reflects the party’s wariness, but it still may not be enough to stop him, and if he becomes the nominee again, the groups will likely fall in line to support him, according to Rick Wilson, the co-founder of anti-Trump group the Lincoln Project. 

“They would love to be rid of him, but they’re whistling past the graveyard,” Wilson said. “They all understand that Trump still has this sort of Protean power inside the GOP where the base still loves him.”

Catsimatidis, an influential Manhattan Republican, says he has reservations about Trump’s ability to build a coalition of support to win the White House a second time.

“I think Donald Trump is a very, very smart guy, but he tends to make new enemies every day,” Catsimatidis said. “That’s the thing about him I don’t like. I’m in the business of making new friends and no enemies.”

--With assistance from Bill Allison.

(Updates with poll showing DeSantis leading Trump in 11th paragraph)

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