Bill Cassidy loses Louisiana Republican Senate primary, ending long Senate run

Bill Cassidy’s loss in Louisiana underscored a hard truth for Republicans heading into 2026 and beyond: crossing Donald Trump can still carry a steep price in a primary built to reward loyalty and punish independence. Cassidy, one of the few Senate Republicans who voted to convict Trump after the Jan. 6, 2021, Capitol riot, was defeated in his bid for reelection as Trump-backed Rep. Julia Letlow and state Treasurer John Fleming moved ahead in the Republican field.

The result ended Cassidy’s two-decade career in public office and closed a Senate run that began when he ousted Democratic Sen. Mary Landrieu in 2014. He then won reelection in 2020 with more than 50 percent of the vote and avoided a runoff, but the political terrain in Louisiana changed after the state adopted closed party primaries in 2026, reshaping how voters selected nominees and adding confusion to several races.

Trump made the contest explicit. He endorsed Letlow in January and attacked Cassidy on Truth Social on election day, calling him a “disloyal disaster” and urging Republicans to back Letlow instead. Cassidy’s vote to convict Trump had already made him one of the most exposed Republicans in Washington, and the Associated Press identified him as one of only three remaining Republican senators who voted to impeach the former president.

The Louisiana race also showed how little room remains in the GOP for high-profile dissent on Trump’s terms. Cassidy had clashed with the Trump administration and Health and Human Services Secretary Robert F. Kennedy Jr. over vaccine policy and public-health issues over the past year-plus, deepening the split between the senator and the party’s dominant figure. In Louisiana’s ruby-red terrain, where the Republican nominee is expected to be the heavy favorite in November, the primary has become the decisive battlefield.

If no candidate won a majority, the top two Republicans were set to advance to a June 27 runoff. AP’s 2026 election calendar listed the Louisiana Senate primary on May 16 and the runoff on June 27, putting the contest squarely inside a year already shaped by redistricting fights and Trump’s intervening hand in Republican Senate races nationwide. Cassidy’s defeat sent a clear message to other GOP incumbents: in a party still organized around Trump, survival may depend less on independence than on obedience.