Sen. Bill Cassidy suffered a decisive defeat in Louisiana's Republican Senate primary on May 16, 2026.
The incumbent finished third with 23 to 25 percent of the vote. Rep. Julia Letlow captured roughly 44 percent while state Treasurer John Fleming took 28 to 30 percent, according to tallies reported by the Associated Press. Letlow and Fleming will meet in a June 27 runoff to decide the GOP nominee.
Cassidy's loss traces directly to his 2021 vote to convict Donald Trump in the Senate impeachment trial. That single vote drew sustained attacks from Trump and energized primary challengers who pledged unwavering loyalty to the former president.
"A loss for the country," said former Sen. Mitt Romney. The two senators had both voted to convict Trump, a stance that isolated them from much of the Republican base.
Cassidy addressed the outcome in his concession remarks. He stated that power should not focus on one individual. The comment underscored his long-standing argument for institutional checks within the party.
The New York Times detailed how Trump's repeated criticisms of Cassidy shaped the primary contest and boosted the two challengers. NPR examined the broader fallout for Republicans who broke with Trump on impeachment. Those reports placed Cassidy's defeat in the context of ongoing party tensions that began years earlier.
Voters in Louisiana delivered a clear verdict. Letlow's strong showing reflected her alignment with Trump on key issues including immigration and judicial appointments. Fleming positioned himself as a fiscal conservative with deep roots in state government.
Cassidy had represented Louisiana in the Senate since 2015. His willingness to cross Trump on the impeachment trial proved costly in a state where the former president maintains strong support among Republican primary voters.
The June 27 runoff will test whether Letlow can consolidate the anti-Cassidy vote or whether Fleming can expand his base. Both candidates have received Trump endorsements in recent weeks, intensifying the focus on loyalty to the former president.
Results from the primary showed strong turnout in rural parishes where Trump performed well in 2024. Urban areas delivered fewer votes for Cassidy than in previous cycles, signaling a shift in the state's Republican electorate.
