President Donald Trump’s power as the GOP’s kingmaker faces a major test with this month’s primaries. So far, he’s on rocky footing.

His revenge tour kicks off Tuesday in Indiana, as he tries to oust eight Republican state legislators who blocked his redistricting effort there. Then it moves on to Louisiana and Kentucky, where he’s backing challengers to two longtime enemies, Sen. Bill Cassidy and Rep. Thomas Massie, who he’s been itching to unseat for years. Trump has also selected his favorite candidates in the crowded GOP primaries for Alabama Senate and Georgia governor.

But his picks have struggled to dominate their fields, with most holding only narrow leads in polling and some failing to pull far ahead in fundraising. In Indiana, even a few allies of the president are tempering expectations of a full eight-lawmaker sweep.

The results will reveal how effective the president’s political operation is at turning out Republicans when Trump is not on the ballot, and how motivated MAGA is to go along with his ongoing retribution campaign. It’s also a potent expression of his power ahead of the likely lame-duck phase of his presidency.

Some Republicans — even those involved in the races — say the shaky standing of Trump’s preferred candidates suggests that his ability to move his base en masse is beginning to slip. MAGA, they note, may be developing a mind of its own as the party begins to look beyond the Trump era.

“He’s hit his max power and now you’re seeing the backside of that power curve,” said former GOP Rep. Adam Kinzinger, a frequent target of Trump’s wrath who retired from Congress amid intense backlash for his 2021 vote to impeach the president and a new congressional map that would have left him in a member-on-member primary. “This will be his last competitive election cycle that will have any impact on him. And I think the base is starting to think into the future.”

Trump has a long history of unseating his congressional opponents, backing primary challengers to his critics and wielding his social media platform and his official bully pulpit to create such politically hostile conditions that many of his adversaries simply retire. Republican candidates have long jockeyed — and continue to trip over themselves — for his stamp of approval, hoping not to end up on the wrong side of his anger.

“The Trump endorsement is the most powerful and influential endorsement in the history of American politics,” said White House spokesperson Davis Ingle. “President Trump’s sterling record with his endorsements speaks for itself.”

Still, he’s produced a very mixed track record in contested races. Trump’s candidates have felled some of his biggest foes in GOP primaries, including former Rep. Liz Cheney (R-Wyo.) and other Republicans who voted to impeach the president in his first term. But he’s also suffered some high-profile losses; he failed to oust Georgia Gov. Brian Kemp and has watched several of his picks fall short in congressional races over the years, including Sen. Luther Strange in Alabama and scandal-plagued Rep. Madison Cawthorn in North Carolina.

Success will be even trickier this cycle: The May contests come as he continues an unpopular war in Iran that’s causing voters pain at the gas pump, as people sour on his economic and immigration agenda and as his approval ratings continue to sink.

“The [Trump] endorsement just isn’t moving voters. It just isn’t,” said a GOP operative working on the Alabama Senate race who was granted anonymity to speak candidly. “When you’ve endorsed more than 800 people in 10 years, the potency of an individual endorsement wanes.”

May 5: Indiana

As the redistricting wars become a defining element of the midterms, Tuesday’s election will illuminate the president’s ability to maintain his grip on the Republican coalition.

While the White House and its allies have deployed the full force of its political operation against eight Indiana legislators — spending nearly $10 million across the races — they’re beginning to downplay the likelihood they will sweep all of them. Critics of the revenge effort say the strategy has been scattered and undisciplined.

How many incumbents survive will be an important piece of evidence predicting how the rest of May will go for the White House.

“We’ve tried to be helpful, as we always are, with our colleagues that are incumbents right now and will continue to be,” Rodric Bray, Indiana’s Senate President Pro Tempore who led the charge against Trump’s redistricting push, told Blue Light News. “The challenge, of course, is that money matters in politics. When $9 million is spent, that has a huge impact, and we’ll see what the result is.”

May 16: Louisiana

Trump-backed Rep. Julia Letlow is struggling to dominate the polls in her primary challenge to unseat Cassidy, who earned MAGA’s ire for voting to convict Trump on impeachment charges in 2021. The latest Emerson College poll shows Letlow locked in a close three-way race, with her at 27 percent, State Treasurer John Fleming at 28 percent and Cassidy at 21 percent. Nearly 1 in 4 likely GOP primary voters are undecided.

Letlow entered the race at Trump’s urging. She boasts endorsements from Louisiana’s GOP Gov. Jeff Landry and national groups like the Make America Healthy Again PAC, which has promised $1 million in support like distributing mailers — a needed financial boost given her middling war chest compared with Cassidy’s.

But Trump has not sent the calvary for Letlow, withholding his own war chest and not making any trips to Louisiana on her behalf. The president recently doubled down on his campaign against Cassidy, telling GOP primary voters to kick the incumbent “OUT OF OFFICE” — but Trump notably did not name-drop Letlow or urge voters to back her.

May 19: Kentucky, Alabama and Georgia

Trump faces two very different tests of his influence in Kentucky, where he is simultaneously boosting Rep. Andy Barr as retiring Sen. Mitch McConnell’s successor and pushing to oust a longtime thorn in his side in Massie.

The president waded in late for Barr, endorsing the representative less than three weeks before the primary while also offering one of his two rivals, businessman Nate Morris, a job in his administration — a move that could help propel Barr past former Kentucky Attorney General Daniel Cameron.

But it is Massie’s 4th District race that may prove more troublesome for Trump. The president finally fronted a challenger to the renegade Republican after Massie voted against the party’s signature tax-and-spending package last year, and Trump’s allies have now poured over $10 million into sinking the incumbent.

So far, Massie has withstood the onslaught. He leads his rival, former Navy SEAL Ed Gallrein, in polling, fundraising and name ID. One recent survey showed half of likely voters in his deep-red district with a libertarian bent preferred an independent-minded lawmaker, compared to 37 percent who wanted a strong Trump supporter.

Massie, who threads that needle by saying he’s with Trump “91 percent of the time,” argues that supporting him and the president aren’t “mutually exclusive things.” And he thinks the Trump-directed flood of outside money against him has its limits.

“If outside billionaires spend millions of dollars, they can change somebody’s profile,” Massie said in a recent interview. “But I think what they’re going to find out is that my brand is established well enough … that [they] can persuade some of the people, but they’re not going to be able to persuade enough of them.”

The president isn’t being driven by revenge in Alabama. But even there, his chosen candidate is battling to break through a crowded GOP primary field for Senate: The Trump-backed Rep. Barry Moore has a slight lead in public polling, while Attorney General Steve Marshall, who has been in office for nearly a decade, is holding his own.

Meanwhile in Georgia, Trump’s backing of Lt. Gov. Burt Jones’ gubernatorial run is a rebuke of Secretary of State Brad Raffensperger, who rose to national prominence by defying the president’s efforts to overturn the 2020 election and is himself running for governor.

Still, Trump’s endorsement has its limits: Rick Jackson, a health care executive, has a slight lead over Jones in most polls for the GOP primary as he also makes a play for the MAGA base. He’s been pummelling the lieutenant governor with millions spent on attack ads.

“If any other candidate had received that amount of negative, they would be polling within the margin of error of zero,” said a Georgia-based Republican strategist who is unaffiliated with any candidate and was granted anonymity to speak openly. “When you’re looking at the reasons why [Jones] is now in a toss-up race, I would say the President’s endorsement is by far the top reason why.”

As both Jackson and Jones compete for the same slice of voters, some Republicans see Jones’ inability to dominate the race as evidence of Trump’s waning influence.

“It’s not just Donald Trump — Georgia candidates historically have not benefited very much from endorsements from out-of-state celebrities,” said Jason Shepherd, former Cobb County GOP Chair.

May 26: Texas run-off

After Sen. John Cornyn finished ahead of Attorney General Ken Paxton in Texas’ March primary, Republicans in Washington were on standby for Trump’s expected endorsement. It never came.

Perhaps in the clearest example of MAGA beginning to make decisions without Trump’s explicit approval, Texas Republicans have rallied around the scandal-plagued Paxton. Polling now shows that a Trump endorsement for Cornyn, at this point, likely wouldn’t sway voters significantly — and Paxton would maintain his edge.

GOP Texas consultant Vinny Minchillo that if Trump does decide to weigh in, he “will have to sell this to the faithful and tell them exactly what to do. Especially if he endorses Cornyn.”

Trump’s endorsement still matters, he said, but “less so with each day that passes.”