U.S. President Donald Trump tightened his grip over the Republican Party on Tuesday after Kentucky Congressman Thomas Massie lost a high-profile primary battle to Trump-backed candidate Ed Gallrein.

Massie, once popular among conservative grassroots voters, had increasingly clashed with Trump over issues including the Iran war, aid to Israel and the release of files linked to convicted sex offender Jeffrey Epstein.

With nearly all votes counted, Gallrein secured around 55% of the vote, defeating Massie in what became the most expensive House primary race in U.S. history.

Trump’s influence dominates Republican politics

The result highlighted Trump’s continued dominance inside Republican primary politics, where loyalty to the former president remains a decisive factor.

Massie had angered Trump after voting against the president’s “Big Beautiful Bill” tax package and helping push for the public release of Epstein-related Justice Department files.

His criticism of military involvement in Iran and support for a more isolationist foreign policy also triggered heavy opposition from pro-Israel groups and Trump-aligned political organisations.

More than $32 million was reportedly spent during the race, with outside groups flooding Kentucky with advertisements attacking Massie as disloyal to Trump and the Republican Party.

One controversial campaign advert even used AI-generated imagery to portray Massie alongside progressive Democratic lawmakers.

‘Massie got Trumped’

Republican strategist T.J. Litafik summed up the outcome bluntly: “Massie got Trumped.”

The race followed a pattern already visible in recent Republican primaries, where several Trump critics and dissenting lawmakers have either lost or come under increasing political pressure.

Another Trump critic, Senator Bill Cassidy of Louisiana, also recently lost his primary contest, reinforcing the risks faced by Republicans willing to publicly challenge the president.

Massie blames outside influence

In his concession speech, Massie joked that he “had to call Tel Aviv” to reach Gallrein a reference to the large amount of pro-Israel funding involved in the race.

Supporters interrupted his speech with chants including “No more wars!” and “America First”.

“We weren’t really running against Ed Gallrein. We weren’t running against Donald Trump. We were running for what we believe in,” Massie told supporters.

Meanwhile, Gallrein promised to support Trump’s agenda in Washington and described himself as a “team player” who would help put “America First”.

Bigger battle ahead before midterms

The Kentucky race is being closely watched as an indicator of how Republican politics may shape up ahead of the November midterm elections.

While Trump continues to dominate Republican primaries, analysts say questions remain about whether that influence will translate into broader national support as concerns grow over inflation, fuel prices and foreign policy tensions.

(with inputs from Reuters)