US Rep. Thomas Massie's GOP primary in Kentucky is the latest test of Trump's power over the party

CRESTWOOD, Ky. (AP) — Republican voters in northern Kentucky will choose between U.S. Rep. Thomas Massie and challenger Ed Gallrein in Tuesday's House primary, another test of President Donald Trump's power over his party after he handpicked Gallrein to take on the incumbent.

The primary race turned white hot in the final stretch. Massie brought in a phalanx of other Republicans, including Rep. Lauren Boebert, in an attempt to show voters that they could support both him and Trump. Trump ratcheted up his social media attacks on Massie, calling him “an obstructionist and a fool,” and Gallrein shared a stage with Defense Secretary Pete Hegseth on Monday.

Trump has tightened his grip on the Republican Party in his second term, successfully purging those who deviate from his agenda, but Massie is one of the last and most outspoken holdouts. A Massie defeat on Tuesday would serve as one of the most powerful demonstrations yet of Trump’s influence over Republican voters.

The matchup between the congressman, who has been in office since 2012, and a first time candidate running on his loyalty to Trump has become the most expensive U.S. House primary in history.

Massie challenged the president last year to release the Jeffrey Epstein files, which became a political drag for the White House. He has also criticized the war in Iran and refused to vote for Trump's signature tax legislation over concerns that it would increase the national debt.

Trump visited Kentucky to boost Gallrein in March. The president has had a string of success defeating dissenters in his party, pushing to oust Sen. Bill Cassidy in Louisiana and several Indiana state senators who defied him on redistricting.

The winner of Tuesday's primary is expected to take the general election in the deeply red 4th Congressional District, which stretches along the state's northernmost border.

Republicans statewide will also choose their nominee to replace Mitch McConnell, the longtime U.S. Senate leader, in a contest that represents a generational changing of the guard for the party. Rep. Andy Barr, endorsed by Trump, faces Daniel Cameron, a former state attorney general.

Can Republican voters support both Trump and Massie?

Massie's challenge is to win over voters who generally think favorably of Trump, the same man telling them to vote for Gallrein. It's not the first Republican primary Trump has tried to sway, but Massie's overt rebelliousness has been a particular challenge to the president.

Gallrein, a retired U.S. Navy SEAL, embraced the role Trump gave him, focusing his pitch to voters on his personal history and unwavering loyalty to the president. Massie, he argued, betrayed Trump and the party.

Hegseth made a visit to the district Monday to boost Gallrein and lambast Massie, a break from tradition that came while the nation is at war. Hegseth said he was speaking “as a private citizen.”

Some voters were already fed up with Massie bucking the party.

George Scherzer, who lives in the small town of Crestwood, Kentucky, supported Massie in past elections but didn’t like the congressman’s lack of support on some of the president’s agenda, including last year’s tax and spending bill, known as the One Big Beautiful Bill.

“Some of his votes just did not make sense to me,” he said.

Massie has argued that voters do not have to choose between Trump and him, noting that he voted with his party the vast majority of the time. As for the remainder, he said those were on proposals that violated his America First principles such as adding to the national debt and getting into military entanglements, such as the war with Iran.

Massie has voted against U.S. aid to Israel and has faced accusations of antisemitism. He has denied the charges, arguing he's generally against all foreign aid. But the race has drawn in millions of dollars against him from pro-Israel interest groups, including from the Republican Jewish Coalition Victory Fund.

That's become a stump topic for Massie, who says the attempt to oust him is to send a warning to other lawmakers who oppose the president or aid to Israel.

In a pitch to Kentucky Republicans, Boebert posted photos both of her with Massie and with Trump on X, and wrote, “I support both of these men.” Replying to Boebert's message on X, Massie said, “she likes both Trump and me! Yes it’s possible!!”

Trump lashed out at Boebert on Truth Social, asking for a Republican to challenge her even though the filing deadline in her home state of Colorado has already passed. “Anybody that dumb deserves a good Primary fight!” he wrote.

McConnell goes largely unmentioned in primary for his seat

Barr and Cameron have tiptoed around their relationship with McConnell, who they previously worked under.

McConnell criticized Trump over the Jan. 6, 2021, attack on the U.S. Capitol and more recently voted against some of his Cabinet picks. He is stepping down after he becoming the longest serving Senate leader in American history, coinciding with a transformation of the party under Trump.

Many Republicans, while admiring McConnell's achievements, see him as out of step with the Make America Great Again and America First movements spawned by Trump. Both Barr and Cameron have taken note, and while ingratiating themselves to the president have put some distance between themselves and McConnell.