WASHINGTON — The Kentucky rumble over Rep. Thomas Massie’s seat in Congress is the most expensive House primary race in US history, with tens of millions of dollars spent on political advertisements and President Trump demanding that the libertarian-minded Republican be beaten.

Massie is running for an eighth term representing the Bluegrass State’s Fourth Congressional District and facing a tough challenge from Trump-endorsed GOP opponent Ed Gallrein over past votes opposing the president’s agenda and fueling controversy about the administration’s Jeffrey Epstein disclosures.

The primary election poses another opportunity to test the president’s grip on the Republican Party after the defeat of longtime Sen. Bill Cassidy (R-La.) against Rep. Julia Letlow (R-La.), who was backed by Trump, on Saturday.

In a rare move, Secretary of War Pete Hegseth also appeared Monday at a campaign rally to stump for Gallrein, who has served multiple combat deployments and received four Bronze Stars for valor.

“President Trump does not need more people in Washington who are trying to make a point, especially from his own party. He needs people willing to help him win, to vote with him,” Hegseth chided during the rally.

Defeating Massie has been the top priority of Trump’s so-called revenge tour against Republicans who defy him. It is also, perhaps, the ultimate test of his endorsement power in GOP circles this election cycle.

Last year, Trump brought in the big guns, including his 2024 co-campaign manager, Chris LaCivita, and pollster Tony Fabrizio, who took charge of the Kentucky MAGA super PAC with the explicit goal of taking Massie down.

“The worst Congressman in the long and storied history of the Republican Party, is Thomas Massie,” Trump roared on his Truth Social Monday. “He is an obstructionist and a fool. Vote him out of office tomorrow, Tuesday. It will be a great day for America!”

As of Monday, at least $32.6 million has gone toward political ad spending for the primary, with Gallrein, a retired Navy SEAL, shelling out nearly $11 million and Massie forking over $7.6 million, according to the firm AdImpact.

Unlike some of Trump’s other GOP foes, like Cassidy, the five Republicans in Indiana who defied him on redistricting, and more, Massie still has considerable clout with elements of the base.

Massie has attracted support from former Rep. Marjorie Taylor Greene, Rep. Lauren Boebert (R-Col.), Rep. Victoria Spartz (R-Ind.), Sen. Rand Paul (R-Ky.), and more. He’s also polled much stronger than other GOPers in Trump’s crosshairs this cycle.

A May 15 public survey from Big Data Poll found Massie narrowly besting Gallrein, 50.6% to 49.4%, with the Kentucky rep having lost support since the firm’s last analysis in April.

Nearly $8 million has funded attack ads on Massie, while more than $6 million has been spent on attack ads against Gallrein.

One artificial intelligence-generated ad accused the congressman of being “caught in a throuple” with “Squad” Reps. Ilhan Omar (D-Minn.) and Alexandria Ocasio-Cortez (D-NY) after voting against Trump’s One Big Beautiful Bill and other priorities. Massie called the ad “defamatory.”

Pro-Israel groups like the American Israel Public Affairs Committee and the Republican Jewish Coalition have also funneled contributions to Gallrein’s effort to unseat Massie, who has also voted with the “Squad” pols against billions of dollars in US funding for Israel’s missile defense systems and against resolutions affirming support for the Jewish state.

Massie has framed his race as “a referendum on whether Israel gets to buy seats in Congress” — despite the groups involved being run by Americans and funded by US donors.

Meanwhile, a pro-Massie PAC has highlighted Gallrein shifting his party affiliation to independent following Trump’s election to the presidency in 2016, slamming the now-GOP candidate as “Woke Eddie” after changing his registration back when Joe Biden was in the White House.

Trump has said the Navy captain is straight out of “central casting” and, when announcing his endorsement last October, “a true America First Patriot” — while Massie has been focused on “making life very easy for the Radical Left.”

One month later, the president had to sign a law forcing the Department of Justice to release investigative materials on the prosecutions of now-deceased sex trafficker Jeffrey Epstein and his accomplice Ghislaine Maxwell.

Massie co-authored the legislation and helped generate enough support with a handful of Republicans and most Democrats to pass it through Congress.

The Epstein controversy has become a massive headache for the Trump administration during the 2026 midterm elections, as Democrats and their allies expressed outrage over a purported “cover up” of possibly incriminating information about the late financier’s powerful and influential associates.

No such evidence has emerged after the DOJ released more than 3 million pages of documents, as well as tens of thousands of photos and videos, to the public about the pedophile, who committed suicide on Aug. 10, 2019, while awaiting trial on sex trafficking charges.

A prior review, completed by the DOJ and FBI in July 2025, determined that Epstein never blackmailed any of his associates and that no third parties could be charged in connection with his sex crimes.

But the botched initial release of federal records on Epstein under former Attorney General Pam Bondi contributed to public backlash that has fueled anti-Trump lawmakers in Congress as well as Massie.

The president’s anger against Massie dates back to 2020, when Trump lashed out at the Kentucky rep. for being a “third-rate Grandstander” for opposing a $2 trillion COVID-19 stimulus package.

But during Trump’s second term, Massie has proven to be an even bigger thorn in the president’s and GOP leadership’s side due to the threadbare House majority and the congressman’s recalcitrance.

Massie has refused to tag along on key party-line votes pertaining to the budget, including the marquee One Big Beautiful Bill Act, citing his concerns about the deficit. He also repeatedly declined to help Republicans pass funding measures during government shutdown showdowns with Democrats.