President Trump has escalated efforts to unseat Republican lawmakers who defied him, focusing on key May primaries in Kentucky, Indiana and Louisiana. High-profile tests include Rep. Thomas Massie’s Kentucky primary on May 19, Indiana state Senate contests on May 5 and Sen. Bill Cassidy’s Louisiana primary on May 16 (with a possible June 27 runoff). The outcome will reveal whether Trump’s endorsements — backed by millions in outside spending — can reshape GOP behavior and chill dissent in Congress.
Trump Tests GOP Loyalty With High-Stakes May Primaries — Massie, Cassidy and Indiana Races in the Crosshairs
President Donald Trump at a rally in Des Moines, Iowa, in July. (Scott Morgan / Bloomberg via Getty Images)(Scott Morgan)
President Donald Trump’s campaign to punish Republicans who have opposed him is entering a decisive phase in May, when primary voters in Kentucky, Indiana and Louisiana will weigh whether to keep incumbents who crossed the former president or replace them with Trump-aligned challengers.
What’s at Stake
Trump and his operation have actively recruited and endorsed candidates, encouraged some contenders to run and others to withdraw, dispatched senior aides to coordinate outside groups and poured millions into television advertising. The effort is widely viewed as a test of whether Trump’s endorsements — alone or backed by heavy outside spending — can reshape Republican behavior in Washington and statehouses.
Key target races include Indiana state Senate primaries on May 5, a Louisiana Senate primary on May 16 (with a potential runoff on June 27), and Representative Thomas Massie’s closely watched Kentucky primary on May 19.
Rep. Thomas Massie, R-Ky., during a House Judiciary Committee hearing in Washington on March 3. (Tom Williams / CQ-Roll Call via Getty Images file)(Tom Williams)
Massie: A Test Case for GOP Dissent
Rep. Thomas Massie (R-Ky.) is perhaps the highest-profile figure in the conflict. A seven-term congressman known for his independence, Massie faces a Trump-backed challenge from former Navy SEAL Ed Gallrein. Outside groups led by Trump ally Chris LaCivita and the super PAC MAGA KY have spent aggressively against Massie — more than $3 million, according to the ad-tracker AdImpact — while the Republican Jewish Coalition has spent over $4 million opposing him.
“They tell me that. I mean, they’ll tell me to my face while we’re voting,” Massie said of colleagues who privately agree with him but decline to take risky votes. “They’re like, ‘Well, you’ve got the right vote here, but, you know, this is not a hill I’m going to die on.’”
Massie argues that if he survives, it would signal greater freedom for dissent within the GOP. If he falls, it could reinforce a culture of loyalty to Trump.
Indiana and Louisiana Contests
In Indiana, Trump has endorsed challengers to seven of eight Republican state senators who resisted his push to redraw congressional maps — an initiative intended to boost Republican chances in House races. Outside groups have spent more than $6 million targeting those lawmakers, according to AdImpact.
Sen. Bill Cassidy, R-La., at the Capitol in 2025. (J. Scott Applewhite / AP)(J. Scott Applewhite)
In Louisiana, Sen. Bill Cassidy, one of seven Republicans who voted to convict Trump in the 2021 impeachment, faces a GOP primary on May 16 against Trump-backed Rep. Julia Letlow and state Treasurer John Fleming. If no candidate wins a majority, the top two will advance to a June 27 runoff. Trump endorsed Letlow and has used outside ads to promote her, but his overall involvement against Cassidy has been less intense than in the Massie fight.
Money, Messaging and Loyalty
AdImpact reports that 70% of TV ads in these Indiana, Kentucky and Louisiana races mention Trump by name. Candidates on both sides reference the former president: Cassidy’s ads highlight cooperation with Trump on tax cuts, while some incumbents in Indiana tout their work extending Trump’s legislation at the state level even as Trump backs their opponents.
Trump’s team has also worked behind the scenes: bringing potential candidates to the White House, pressuring some would-be contenders to withdraw and directing photographs and meeting footage into campaign materials. The strategy mixes endorsement power with coordinated outside spending and political pressure.
Political Calculus for the GOP
Some Republicans worry that devoting time and money to primaries in strongly Republican states diverts resources from competitive general election battlegrounds. Supporters of Trump’s approach counter that primary voters in these districts favor challengers who back the former president and that reshaping the GOP now could pay long-term dividends.
As the May contests play out, they will offer a clear signal about whether Trump’s endorsement remains the dominant force in GOP primaries or whether voters and candidates require more than his backing — namely, organized field operations and deep ad spending — to prevail.
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