Former Navy SEAL Ed Gallrein has won the Republican primary in Kentucky’s 4th Congressional District over Rep. Thomas Massie, NBC News projects, notching another win for President Donald Trump in his push to eliminate political rivals and roadblocks within his own party.Gallrein beat Massie in the most explosive fight of Trump’s political pressure campaign, which wended its way from Indiana and Louisiana to Kentucky this month, all featuring primary challengers he endorsed. Gallrein was aided by an extraordinary advertising blitz fueled largely by pro-Trump and pro-Israel groups.Massie, first elected to the House in 2012, had become an ever-present thorn in Trump’s side. Trump traveled to the district in March to throw his political weight behind Gallrein and slammed Massie as a “disaster.” Known as an anti-war libertarian and deficit hawk, Massie drew ire from Trump and his allies for opposing the war in Iran, as well as Trump’s “big, beautiful bill” spending package. Massie, along with Rep. Ro Khanna, D-Calif., also was one of the chief proponents of releasing the Justice Department’s files related to investigations of the late sex offender — and onetime Trump friend — Jeffrey Epstein.Massie’s prospects of outmaneuvering Trump became even more tenuous over the final days of the race. Rep. Thomas Massie and challenger Ed GallreinGetty Images; APIn Louisiana, Sen. Bill Cassidy, a Republican who similarly got crosswise with Trump, failed to advance from the party’s primary in his re-election bid Saturday, underscoring how unflinchingly loyal GOP voters remain to Trump.And when Rep. Lauren Boebert, R-Colo, campaigned with Massie, Trump threatened to revoke his endorsement of her.Meanwhile, Defense Secretary Pete Hegseth traveled to Kentucky on Monday for a last-minute appearance with Gallrein — an unusual and overtly political move for a defense secretary but one the Defense Department said Hegseth was making in his personal capacity.“There’s a portion of the electorate who doesn’t believe that Congress should be independent,” Massie said in an interview last month. “They believe that, when the Republicans control the White House and the Congress, that Congress should just do whatever the president wants. But that’s not how our government’s set up.”Massie faced an onslaught of ads, many of them negative, led by MAGA KY, a super PAC directed by Trump adviser Chris LaCivita. The group’s attacks focused in part on immigration and border security provisions in Trump’s spending bill. Pro-Israel groups affiliated with the Republican Jewish Coalition and the American Israel Public Affairs Committee, or AIPAC, also poured millions of dollars onto the state’s airwaves to boost Gallrein.Spots promoting Gallrein or attacking Massie accounted for more than $19 million of the $33 million spent on advertising in the primary, according to AdImpact, an ad-tracking firm. But pro-Massie forces made noise, as well. The Massie-aligned Kentucky 4th PAC aired a spot called “Tucked Tail And Ran” that used war imagery to emphasize Gallrein’s departure from the GOP during Trump’s first term. The ad depicted Gallrein leaving Trump behind in a foxhole.Gallrein kept a low profile, choosing to let Trump’s endorsement speak for him and drawing criticism from Massie for dodging debates and other candidate forums.“It’s like they have a tracker on my car and keep from getting within 50 miles of me,” Massie said last month. “He is scared to answer any question, even if I don’t get to ask the questions.”Massie’s defeat follows other losses this month by Republican state lawmakers in Indiana who had resisted a Trump-backed congressional redistricting push. Five challengers endorsed by Trump defeated sitting state senators in their primaries. Another Trump victory came Saturday in Louisiana, where Cassidy, who had voted to convict Trump in his impeachment trial after the Jan. 6, 2021, attack on the Capitol, finished third in his re-election primary. Trump-endorsed Rep. Julia Letlow and state Treasurer John Fleming advanced to a June 27 runoff.Massie told NBC News last month that the outcome of his primary could determine whether more Republicans and Congress are willing to stand up to Trump.“They’re trying to decide,” Massie said, “could they win an election?”