Trump and Don Jr. go to war with top GOP donor who bought ads opposing his candidate

Former President Donald Trump's endorsement of "Hillbilly Elegy" author J.D. Vance has sparked a civil war between Trumpworld and one of the Republican Party's biggest donors.

Trump last week endorsed Vance, a venture capitalist whose campaign is financially backed by billionaire Peter Thiel, in the Ohio Republican Senate primary. The move sparked backlash from Republicans in the state who have criticized Vance for making anti-Trump statements in the past. Trump expected the conservative Club for Growth, which spent more than $65 million to elect Republicans last campaign cycle, to drop their backing of Vance opponent Josh Mandel but the group doubled down instead, according to The New York Times' Maggie Haberman.

The Club for Growth aired new ads in Ohio on Thursday featuring quotes from Vance criticizing Trump. Vance strongly opposed Trump during the 2016 campaign, blaming "racism" and "xenophobia" for his rise. Vance called Trump "reprehensible" and in a private text message reportedly worried that Trump would become "America's Hitler."

The ad shows Vance describing himself in a 2016 interview as a "Never Trump guy" and shows one of his old tweets where Vance described Trump as an "idiot."

Trump, who seems to have forgiven Vance after repeated trips by Thiel and the candidate to his Mar-a-Lago resort and Vance's rebranding as a far-right culture warrior, lashed out at Club for Growth over the ad buy, directing his assistant to send a note to David McIntosh, the group's president.

"Hi Mr. McIntosh. The President shares this message with you: Go f**k yourself," the message said, according to Haberman.

But the message seems to have backfired.

"We are increasing our ad buy for Mandel, a Club for Growth spokesperson told Politico's Natalie Allison.

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McIntosh appeared at Trump's rally in North Carolina just days earlier, where Trump touted him as a "very powerful man" and praised him for the group's massive spending.

Donald Trump Jr., who has been increasingly involved in campaigning for his favored candidates, also lashed out on Twitter.

"The RINO frauds attacking [Vance] HATE him precisely because they know he will shake up the establishment," Trump Jr. tweeted on Thursday along with a clip of him stumping for Vance in Ohio.

Trump Jr. also went after Mandel, tweeting a montage of the candidate appearing in the past with Trump foes like Sen. Mitt Romney, R-Utah; former Sen. John McCain, R-Ariz.; and former Ohio Gov. John Kasich.

"One of the things that's setting me apart right now is how strongly antiestablishment I am," Mandel says in a clip from an interview, adding that he's taking on "squishy establishment Republicans" like Romney before the video shows him campaigning with Romney, who voted kick Trump out of office during his impeachment trial.

"Ohio friends – Meet the real [Josh Mandel]," Trump Jr. tweeted. "The Club for Chinese Growth backed establishment candidate."

A source close to Trump Jr. told Haberman that he is considering opposing all candidates newly endorsed by the Club for Growth unless they pull the anti-Vance ads and remove McIntosh from its board.

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Such a move would put the GOP in a precarious position. The Club for Growth poured $15 million into the North Carolina Senate primary to boost Trump-backed candidate Ted Budd into first place, drawing complaints from a Republican opponent that the group was trying to "buy a Senate seat." The group's affiliates have also poured millions to back other Trump-endorsed candidates after getting big donations from Trump billionaire donor Richard Uhlein and GOP mega-donor Jeff Yass. The deep-pocketed group has raised more than $38 million in the past year, according to Open Secrets data.

But the Club for Growth also backs candidates opposed by Trump, like Alabama Senate candidate Rep. Mo Brooks, whom Trump un-endorsed for not defending his election lies enough, and former Rep. Matt Salmon, R-Ariz., who is challenging Trump-backed candidate Kari Lake in the Arizona gubernatorial primary.

It's ironic that the Ohio Senate feud seems centered on past comments by candidates ostensibly counter to Trump's agenda given that the club for Growth strongly opposed Trump's candidacy in 2016, spending millions to defeat him before he pulled out the Republican nomination.

The spat underscores Trump's falling influence as he touts himself as a kingmaker with the power to make or break Republican candidacies. A group of 40 county GOP chairs in Ohio sent a letter to Trump ahead of the endorsement urging him not to back Vance.

"This group represents supporters of multiple candidates, with the notable exception of JD Vance," the letter said, arguing that Vance worked in 2016 against his candidacy and referred to Trump's supporters as "racists."

"An endorsement that cuts against your support and legacy in Ohio will only serve to confuse or upset voters," the group said.

Trump's recent endorsement of Dr. Mehmet Oz in the Pennsylvania Senate race also riled his supporters, who blasted him as the "antithesis" of everything Trump stands for and an "anti-gun pro-abortion open borders Hollywood liberal."

In Tennessee, the state Republican Party this week voted to boot Trump-backed House candidate Morgan Ortagus off the ballot after she sparked infighting among the former president's supporters.

But Trumpworld appears to be standing by Trump's controversial endorsements. Trump Jr. campaigned with Vance on Wednesday, bizarrely touting, of all things, Vance's consistency on Trump.

"That's the standout where you've (Vance) kind of been with us all along," Trump Jr. told the Toledo Blade. "J.D. has actually been by far the most consistent and intellectually honest about his positions and everything as it relates to Trump from day one."