President Trump’s grip on Republican primaries is so strong that even candidates he has not endorsed are working overtime to show they are aligned with the party’s dominant figure.
Sens. Bill Cassidy of Louisiana and John Cornyn of Texas have leaned heavily into their pro‑Trump credentials. Yet with their primaries just days away, Mr. Cornyn is still waiting for an endorsement, and Mr. Cassidy is staring down a Trump‑backed challenger.
Kentucky is showing a similar dynamic.
Rep. Thomas Massie has been touting his support for the Trump agenda, but he is fighting for his political life against a Trump‑endorsed opponent — payback for breaking with the president.
All of it points to a simple reality: Despite the Trump‑led Republicans’ struggles in the 2025 off‑year elections, the president, who has been reshaping the party over the past decade, remains king of the Republican jungle.
“President Trump’s endorsement isn’t just the most powerful endorsement in politics today; his endorsement is the most powerful in political history,” said Andy Surabian, Republican strategist and close adviser to Vice President J.D. Vance. “I don’t think we’ve ever seen anything like it from anyone in either party prior to him.”
“A simple Truth Social post from the president can rewire entire elections to the point where GOP primaries have largely become races to get Trump’s stamp of approval, first and foremost,” Mr. Surabian said.
That has created headwinds for Mr. Massie, Mr. Cornyn and Mr. Cassidy. They are struggling to atone for the times they ignored Mr. Trump’s wishes, opening the door for their primary rivals eager to pledge full fealty.
It is still an open question whether the Trump brand can help Republicans in the midterm elections this fall, when a broader electorate will decide control of Congress for Mr. Trump’s final two years in office. The president will soon be 80 and a lame duck.
For now, it is all about the primaries.
Mr. Trump showcased his dominance in recent intraparty battles in Ohio and especially Indiana, where he targeted seven Republican state senators who rejected his push to redraw the state’s congressional map to help Republicans defend their slim House majority this fall. His preferred candidates won five of those races, and one is still too close to call.
The next stop on the Trump revenge tour is in Louisiana on Saturday.
Mr. Cassidy, one of the three remaining Senate Republicans who voted to convict Mr. Trump after the Jan. 6, 2021, riot at the Capitol, is running for a third term.
Since the start of the campaign, Mr. Cassidy has tried to mend fences with Trump supporters. Indeed, his first reelection ad highlighted his work on fentanyl legislation, telling viewers: “President Trump said it was the most important legislation he would sign this year.” The ad includes a photo of him standing behind Mr. Trump at the Oval Office signing ceremony.
Mr. Trump, however, is backing Rep. Julia Letlow in a race that also includes Louisiana Treasurer John Fleming, a former congressman and White House deputy chief of staff.
To avoid a June 27 party runoff and win the nomination outright, a candidate needs to win a majority of the vote. Polls suggest Mr. Cassidy could finish third.
“If you have a big glaring asterisk on your record, with the obvious one being the impeachment vote, you’d better do some, you know, atonement with President Trump before you could hope to get his absolution,” said John Couvillon, a Louisiana‑based pollster working for the Fleming campaign. “Being a longtime incumbent is one thing, but combine that with a bad impeachment vote, and it’s even worse.”
Cassidy campaign manager Katie Larkin said her boss “is endorsed by the top pro-life organization in America and has successfully delivered for Louisiana in conjunction with the president again and again.”
Three days after the Louisiana primary, voters in Kentucky’s 4th Congressional District will decide the fate of Mr. Massie, the libertarian‑leaning Republican who has represented the area since 2012. He has clashed with Mr. Trump over his championing of the release of the Jeffrey Epstein files, his opposition to foreign aid, including to Israel, and his vote against the One Big Beautiful Bill Act, which he said would add more debt for future generations.
Mr. Trump is supporting Ed Gallrein, a retired Navy SEAL who has pledged his fealty to the president.
Mr. Massie is leaning into his independent streak, but he is also running ads that remind voters he supports Mr. Trump and his MAGA agenda.
“Let’s talk about the elephant in the room. I agree with President Trump a whole lot more than I disagree with him,” he says in a recent ad. “President Trump and I have a whole lot more to get done — together.”
From there, the focus will shift to the May 26 runoff in Texas between Mr. Cornyn and Texas Attorney General Ken Paxton.
Mr. Cornyn has angled hard for a Trump endorsement, running ads touting his loyalty to the president and even backing off his decades of opposition to scrapping the legislative filibuster to pass Mr. Trump’s agenda.
His campaign has faced nonstop questions about why Mr. Trump has stayed on the sidelines.
Asked how challenging it has been for Mr. Cornyn to convince voters he has Mr. Trump’s back, even though the president has refused to endorse him, senior adviser Matt Mackowiak replied, “Decline.”
Mr. Trump’s shadow hangs over the coming primaries.
He endorsed Rep. Barry Moore in the 2026 Alabama Republican primary for U.S. Senate.
In Georgia, he is backing Burt Jones in the governor’s race but has stayed on the sidelines in the U.S. Senate contest, where the candidates are vying for the Trump mantle.
In the Kentucky race to replace retiring Sen. Mitch McConnell — who served for years as a frequent foil for Mr. Trump — he gave a dual boost to Rep. Andy Barr.
Mr. Trump endorsed Mr. Barr and persuaded Republican candidate Nate Morris to withdraw from the race to accept a soon-to-be-announced ambassadorship. Former Attorney General Daniel Cameron, often billed as a McConnell protege, is also running.
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