Sen. Bill Cassidy loses Louisiana GOP primary to Trump-backed Letlow and Fleming

Five and a half years ago, after voting to convict President Donald Trump in his impeachment trial, GOP Sen. Bill Cassidy of Louisiana was mobbed by Republican voters as he ran for re-election.

Trump-backed Rep. Julia Letlow and Louisiana Treasurer John Fleming bested Cassidy in Saturday’s GOP primary, according to the Associated Press.

With no candidate receiving more than 50% of the vote, Letlow and Fleming will advance to next month’s Republican nomination runoff. And Cassidy became the first elected Republican senator to lose re-election since Indiana Sen. Richard Lugar in 2012.

Trump won, though not in the voting, because the primary in the solidly red state was the latest test of his support for the GOP nomination and the president’s enormous influence over the Republican Party.

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The Louisiana primary was held a week and a half after the Indiana primary; Here, Trump-backed rivals ousted five Republican state senators who joined with Democrats last December to defeat the president’s push for congressional redistricting in the GOP-dominated midwestern state.

Letlow was backed by Trump even before entering the race in January.

“Not only did he encourage me to get into this race, but to have his complete and total support, wow, it’s been the honor of my life,” Letlow told Fox News Digital on the eve of the primary.

Trump’s support in the nomination race has outweighed his 2024 election victory in a state he carried by 22 points.

“This is the strongest support in the world,” Letlow said, adding that Louisiana Republicans are “big fans of the president.”

Letlow was also supported by Republican Governor Jeff Landry of Louisiana, a prominent Trump ally.

Republican Senate candidate Republican Rep. Julia Letlow of Louisiana speaks with Fox News Digital on the eve of the state primary on May 15, 2026, in Baton Rouge, Louisiana. (Paul Steinhauser/Fox News)

Cassidy, who sought re-election six years ago, was one of seven Senate Republicans who voted to convict Trump in early 2021 after he was impeached by the House of Representatives for his role in the violent attack on the U.S. Capitol on Jan. 6 by his supporters seeking to overturn congressional certification of former President Joe Biden’s 2020 election victory. Trump was acquitted by the Senate.

But since the start of Trump’s second term, Cassidy has supported the president’s agenda and nominees, including the endorsement of Surgeon General Robert F. Kennedy Jr.

But Kennedy and the Make America Healthy Again movement were out for revenge.

That’s because Cassidy, a physician, is skeptical of Kennedy’s efforts to reform the nation’s health policies, including efforts to scale back vaccine recommendations.

And Kennedy allies accused Cassidy, the chairman of the Senate Health, Education, Labor and Pensions Committee, of helping to drop the surgeon general nomination of Casey Means, a close Kennedy ally and leading proponent of MAHA, after Cassidy failed to bring the issue to a committee vote.

Trump, meanwhile, criticized the senator as “a very disloyal person,” and on the eve of the primaries, the president praised Letlow on social media as “America’s Most Honorable First Congresswoman.”

Cassidy highlighted his record serving Louisiana, one of the nation’s poorest states, during two terms in the Senate. And he showed support for Louisiana’s massive oil and gas industry, which makes up about 15% of the state’s workforce.

“When people ask questions like can you work with President Trump, I point out that he signed four bills that I wrote or negotiated,” the senator said in an interview on Fox News Digital on Friday. “In the meantime, we continue to work together.”

And Cassidy praised himself as a “conservative senator who delivers.”

Cassidy and an allied super PAC spent more than $20 million on ads, according to AdImpact, a national ad tracking firm. This total was more than Letlow and Fleming combined.

Some of these ads lampooned Letlow’s past support for diversity, equity, and inclusion (DEI) programs during his tenure at the University of Louisiana at Monroe.

Cassidy said Republican voters were “concerned about his changing stance on DEI. He was all for DEI.”

Defending her record, Letlow told Fox News Digital: “When DEI was introduced to us in 2020, we had no idea what it was at the time, and I witnessed it immediately. I was in higher education at the time. I quickly witnessed the left completely hijacking it, turning it into a Marxist leftist teaching to our children. And so, when I came to Congress for the last five years, I was fighting against that.”

Letlow also faced scrutiny from rivals for failing to disclose more than 200 personal stock and bond trades during the 45-day reporting period required for members of Congress.

He said it was “a reporting error on my financial advisor’s part.” When I realized this was happening, I fixed it immediately. “Since then, nothing like this has happened again.”

And Letlow claimed that Cassidy and Fleming’s criticisms of him about DEI and stock trading were “completely unfounded attacks, desperate attacks.”

Letlow won the congressional seat in 2021 after her husband, Luke Letlow, died six days after being sworn in to the U.S. House of Representatives following his 2020 election victory for the seat he now holds.

Fleming, who served as deputy chief of staff in the White House during Trump’s first term, argued that he was the most conservative candidate in the GOP Senate primaries.

“They clearly see me as MAGA,” Fleming told Fox News Digital, referring to Louisiana Republicans. “I served in various capacities throughout his first administration. I was one of the first members of Congress to support him in 2016.”

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Fleming, meanwhile, claimed that Letlow “is not the prototype of Trump support. She’s more like a Democrat.”

The winner of the Republican runoff will be considered the clear favorite to keep the Senate seat in Republican hands in the general election.