May primaries to test Trump's grip on the GOP

• We're about to get an answer, or at least a hint of Trump's mojo as the midterms approach.

Zoom in: Trump has endorsed challengers to Republican incumbents in Indiana, Louisiana and Kentucky, in each case snubbing lawmakers who dared to resist his demands.

• The White House is deeply involved in Trump's retribution efforts in each states' primary, shaping its favored candidates' strategies and helping them raise money.
• The upcoming primaries "will be MAGA stress tests that demonstrate, and maybe determine, the president's power over both Congress and Republican voters," GOP strategist Matthew Bartlett tells Axios.
• "They could cement Trump's decade-long transition from the GOP party to the MAGA party — or signal lame-duck status."

Here's what's happening behind the scenes in the run-up to these key primaries:

Indiana (May 5)

Trump is dipping into state legislative races to try to unseat five Republican lawmakers who blocked his effort to have the state redraw its congressional map to create two more GOP-friendly districts for this year's elections.

• Despite heavy pressure from the White House, the legislators — James Buck, Travis Holdman, Spencer Deery, Greg Goode and Greg Walker — were key to rejecting Trump's gambit, arguing that it would undermine trust in the state's elections.

Now Trump and his allies are trying to oust them.

• The president met with the incumbents' challengers in the Oval Office, and is "dialed in" on each race, a person familiar with the effort tells Axios.
• Three pro-Trump groups — Indiana Sen. Jim Banks' Hoosier Leadership for America PAC, the Charlie Kirk-founded Turning Point USA and the Club for Growth — are collectively spending more than $4 million on Indiana's primaries.
• It's a stunning sum for state legislative races.

The pro-Trump forces are turning the incumbents' opposition to redistricting into a central issue in the primaries.

• "'America Last' RINO Greg Walker backed a plan to sabotage President Trump and block his MAGA agenda from coming to Indiana," one Club for Growth mailer says.

Louisiana (May 16)

Trump has endorsed GOP Rep. Julia Letlow's primary challenge to Republican Sen. Bill Cassidy, who earned Trump's ire in 2021 by voting to convict the president after he'd been impeached for inspiring the Jan. 6 Capitol riot.

• Letlow has made Trump's endorsement the centerpiece of her campaign, figuring his popularity in Louisiana will catapult her to the GOP nomination.

• Letlow also has the endorsement of a super PAC aligned with Health and Human Services Secretary Robert F. Kennedy Jr., with whom Cassidy has sparred as chair of the Senate's Health, Education, Labor and Pensions panel.

Cassidy, however, is aggressively realigning himself with Trump — even running commercials in which he appears side-by-side with the president.

• Trump has refrained from lobbing attacks at Cassidy, whose vote the president needs to have any hope of passing a stringent voter ID bill.
• Former GOP Rep. John Fleming also is in the race.
• The primary will head to a June 27 runoff if no candidate gets more than 50% of the vote.

Kentucky (May 19)

Trump's political operation has launched a multimillion-dollar effort aimed at unseating Republican Rep. Thomas Massie, a fierce Trump critic whom the president has called a "moron."

• Massie has slammed Trump over his administration's handling of the Epstein files, opposed the president's "big, beautiful" tax and spending bill, and called Trump's war in Iran "not America First."
• Those were risky moves for Massie: Trump received 64% of the vote in his district in 2024.

Trump is heavily invested in the Kentucky race.

• The White House was involved in recruiting Navy SEAL veteran Ed Gallrein to challenge Massie.
• Trump recently campaigned in the district, and the pro-Trump MAGA KY super PAC has spent $2.64 million on the race.
• Massie's team is expressing confidence, but so is Trump's .
• "He's toast," Trump 2024 co-campaign manager Chris LaCivita said of Massie this week.