Trump Endorses Challenger to Sen. Bill Cassidy in Louisiana Republican Primary

Five years after Sen. Bill Cassidy voted to convict Donald Trump in his second impeachment trial, the bill has come due. On May 16, 2026, Louisiana Republican voters decide whether to renominate a two-term senator who chairs one of the most powerful committees in Congress — or replace him with Rep. Julia Letlow, a 43-year-old congresswoman carrying Trump's "Complete and Total Endorsement" [1]. The race is the last major test of whether defying Trump on January 6 remains an unforgivable sin in the Republican Party.

The Endorsement That Launched a Campaign

Trump's endorsement of Letlow arrived in characteristic fashion — a Truth Social post in January 2026, all caps, exclamation points included. "Should she decide to enter this RACE, Julia Letlow has my Complete and Total Endorsement. RUN, JULIA, RUN!!!" [2]. Letlow announced her candidacy the same day.

The timing was strategic. Cassidy had just assumed the chairmanship of the Senate Health, Education, Labor, and Pensions (HELP) Committee — a position earned through a decade of seniority that gives him significant influence over healthcare policy, education funding, and labor regulations [3]. Trump's endorsement was a direct challenge not only to Cassidy but to the Senate Republican leadership that relies on his committee work.

Cassidy has refused to apologize for his impeachment vote, instead urging voters to evaluate his record. "I haven't disavowed my vote," he told NPR. "But I'm asking voters to look at what I've delivered for Louisiana" [4].

The Polling Picture: Cassidy in Third Place

The numbers paint a stark picture for the incumbent. According to the RealClearPolitics polling average, Letlow leads the field with 33.5%, followed by State Treasurer John Fleming at 25% and Cassidy at 22%, with 19.5% undecided [5]. A Quantus Insights survey from early May showed an even wider gap, with Letlow at 42%, Fleming at 30%, and Cassidy at 20% [5].

Source: RealClearPolitics / Emerson College Polling

Data as of May 14, 2026CSV

An Emerson College poll conducted April 24–26 found that 41% of likely Republican primary voters believe Letlow would be "most supportive of Trump's agenda," compared to just 21% for Cassidy [6]. No candidate appears positioned to clear the 50% threshold required to avoid a June 27 runoff, making the identity of the top two finishers the critical question.

The Money War: Incumbency Advantage vs. MAGA Enthusiasm

Cassidy holds a substantial fundraising and spending advantage, but it has not translated into a polling lead. His campaign and allied super PAC spent $17.4 million on advertising through early May, compared to $5 million for Letlow's campaign and supporting groups and just $680,000 for Fleming [7].

Source: NOLA.com / FEC filings

Data as of Apr 15, 2026CSV

In direct campaign fundraising, Cassidy raised $2.5 million in the first quarter of 2026, while Letlow raised just under $2 million [7]. Outside groups supporting Letlow contributed an additional $3.8 million [7]. The spending disparity — Cassidy's side outspending Letlow's by more than 3-to-1 on ads — has not moved the needle in his favor, suggesting that Trump's endorsement carries a value that money alone cannot match.

The Impeachment Seven: Where Are They Now?

Cassidy is the last of the seven Republican senators who voted to convict Trump to face voters in a competitive race. The fates of his six colleagues offer a cautionary tale.

Source: NBC News / NPR

Data as of May 16, 2026CSV

Three — Richard Burr of North Carolina, Pat Toomey of Pennsylvania, and Ben Sasse of Nebraska — chose retirement rather than face primary voters [8]. Mitt Romney of Utah also retired, though he cited broader concerns about the direction of American politics. Lisa Murkowski of Alaska won reelection in 2022, though she benefited from Alaska's nonpartisan ranked-choice primary system that allowed her to bypass a traditional Republican-only contest [8]. Susan Collins of Maine has avoided drawing a Trump-backed challenger, in part because Republicans calculate she is the only GOP candidate who can win statewide in a blue-leaning state [8].

Across both chambers, 11 of the 17 Republicans who voted to impeach or convict Trump have either retired or lost primary bids [9]. The pattern is clear: defying Trump on January 6 has been politically fatal for most who did so.

The Case for Cassidy: Seniority and Federal Dollars

Cassidy's strongest argument is transactional: he has delivered money to Louisiana that a freshman senator could not replicate. His work on the Bipartisan Infrastructure Law — which he helped negotiate — has sent an estimated $10 billion to the state for roads, bridges, broadband, and coastal resiliency [10].

Specific allocations include $206 million in FEMA flood mitigation funding (the second-highest of any state), $137.5 million for the Morganza to the Gulf hurricane protection project, and $293 million secured in the most recent appropriations cycle [11] [12]. Cassidy's office notes that he delivered more earmarked funding than any senator not on the Appropriations Committee, according to a CQ Roll Call analysis [10].

His committee portfolio — HELP (chair), Finance, Energy and Natural Resources, and Veterans' Affairs — touches nearly every major policy area relevant to Louisiana [3]. On energy, he has pushed carbon capture investment, securing $5.1 billion through the SCALE Act, a significant benefit for Louisiana's petrochemical corridor [11]. On coastal erosion, his position on the Energy and Natural Resources Committee allowed him to advance legislation dedicating billions in Gulf of Mexico energy revenue to coastal restoration [12].

Republican power brokers in the state, however, have not rallied behind him. Gov. Jeff Landry, a Trump ally, endorsed Letlow [5]. The state Republican Party has not formally intervened, but Landry's support for Letlow — combined with his push to adopt closed party primaries that exclude independent and Democratic voters — has structurally disadvantaged Cassidy [13].

Julia Letlow: MAGA Credential and DEI Baggage

Letlow entered Congress in 2021 through tragedy. Her husband, Luke Letlow, died of COVID-19 complications shortly before he was to be sworn in as the representative for Louisiana's 5th Congressional District. She won the subsequent special election and has since served on the House Appropriations Committee [14].

Her legislative record in the House includes the Parents Bill of Rights Act, which passed the House in 2023, and the Farm Rescue Act of 2025 to authorize advance payments for farmers [14]. She sits on Appropriations subcommittees covering agriculture, health, and national security — positions relevant to Louisiana's economy.

But Letlow carries vulnerabilities that Cassidy and Fleming have aggressively exploited. Before entering politics, she worked at the University of Louisiana at Monroe, where in 2020 she called the school's faculty gender diversity record "shameful" and proposed creating the university's first DEI division [15]. Cassidy's campaign labeled her "Liberal Letlow" and ran ads highlighting these comments [16].

Letlow has responded by arguing that DEI programs she oversaw were "hijacked" by the political left. "DEI six years ago was introduced in higher education as something that could be a tool to encourage students, staff, faculty to work hard and go achieve the American dream," she told Fox News. "I quickly witnessed the left completely hijack any of those efforts and turn it into indoctrination of our students, Marxism, holding people down instead of lifting them up" [15].

Whether this explanation satisfies Republican primary voters who have been conditioned to view DEI as a political epithet remains an open question — but her polling lead suggests it has not been disqualifying.

The Fleming Factor

State Treasurer John Fleming, a former congressman who served in the Trump White House, has complicated what might otherwise be a clean Trump-vs.-Cassidy narrative. Fleming has run as an alternative MAGA candidate, arguing he is more aligned with Trump than Letlow despite lacking the endorsement [17].

His presence fragments the anti-Cassidy vote. In the Emerson poll, Fleming and Letlow were essentially tied at 28% and 27%, respectively, with Cassidy at 21% [6]. If the race goes to a runoff — as appears likely — the question becomes whether Cassidy can consolidate enough support in a two-person race to survive, or whether either Letlow or Fleming becomes the clear anti-incumbent standard-bearer.

Fleming has largely self-funded his campaign, spending $680,000 on advertising [7]. His candidacy has drawn frustration from Trump allies who view him as a spoiler preventing Letlow from winning outright [17].

The Structural Deck: Closed Primaries and New Rules

A critical and underreported element of the race is Louisiana's shift to closed party primaries. Gov. Landry pushed the state legislature to adopt congressional party primaries, replacing Louisiana's traditional "jungle primary" system in which all candidates and all voters participate in a single election [13].

Under the new system, only registered Republicans and "no party" voters can participate in the May 16 primary. This change strips Cassidy of crossover support from moderate Democrats and independents who might have backed him in an open primary [13]. Cassidy himself has complained that the new system "caused confusion" and "disenfranchisement" [18].

The structural change favors candidates who can mobilize the Republican base — and in Louisiana, that base remains overwhelmingly loyal to Trump. Roughly 80% of Louisiana Republicans approve of the president [6].

Historical Precedent: Can Presidents Purge Their Own Party?

Trump's track record in endorsing challengers against Republican incumbents is mixed. According to an NPR analysis, 91% of Trump's endorsed candidates won their primaries overall — but three-quarters of those picks were incumbents already expected to win [19]. When Trump backs challengers against sitting Republican officeholders, his success rate drops to roughly 35% to 40% [19].

The most direct parallel is Trump's 2022 effort to unseat Republican incumbents who crossed him. At the House level, he succeeded in defeating several of the ten Republicans who voted to impeach him, including Reps. Liz Cheney and Jaime Herrera Beutler. But several of those members might have been vulnerable regardless, and Cheney chose to make her opposition to Trump the centerpiece of a presidential campaign rather than fight for her seat [9].

At the Senate level, Trump's record against incumbents is thinner. He did not endorse challengers to Murkowski or Collins, and the senators who were most vulnerable chose retirement. Cassidy is, in effect, the first real test of whether Trump can dethrone a sitting Republican senator through endorsement alone.

What Louisiana Voters Actually Want

Polling crosstabs suggest the primary is driven more by tribal loyalty than specific policy disagreements. The Emerson poll found that Trump's endorsement is the single most important factor for a plurality of Republican primary voters, outranking positions on healthcare, energy, or flood policy [6].

Yet there are fault lines within the electorate. Rural voters in north Louisiana — Letlow's home territory — trend more heavily MAGA and prioritize the impeachment vote as a disqualifying act. Voters in the Baton Rouge suburbs and the I-10 corridor are more likely to weigh Cassidy's committee work and federal funding record [4]. Older Republican voters are more likely to support Cassidy, while younger voters skew toward Letlow [6].

The generational split reflects a broader tension in the Republican Party between institutional power and movement loyalty. Cassidy represents the former: a senator who uses seniority, committee assignments, and bipartisan negotiation to secure material benefits for his state. Letlow represents the latter: a candidate whose primary qualification, in the eyes of many voters, is alignment with Trump.

What's at Stake Beyond Louisiana

If Cassidy loses, the implications extend well beyond one Senate seat. His departure would strip Louisiana of a HELP Committee chairman and the institutional relationships that come with 12 years of seniority. Federal programs he has championed — flood mitigation, coastal restoration, carbon capture — would lose their most powerful advocate [10] [12].

For the broader Republican Party, a Cassidy defeat would send an unambiguous message: there is no statute of limitations on defying Trump. Senators who might otherwise exercise independent judgment on future votes would have one more data point suggesting that crossing the president carries permanent consequences.

For Trump, a win validates his ability to reshape the party in his image, even against entrenched incumbents with strong legislative records. A loss — or a race that goes to runoff without a clear Letlow victory — would suggest limits to his endorsement power.

The May 16 primary may not settle the question. With three credible candidates splitting the vote, a June 27 runoff remains the most likely outcome. But even forcing a two-term incumbent into third place on primary day would mark a significant moment in the ongoing transformation of the Republican Party into a vehicle for one man's political will.