By David Morgan
May 16 (Reuters) - Two-term Republican U.S. Senator Bill Cassidy lost his bid for re-election in Louisiana's primary on Saturday, as Trump-backed challenger Julia Letlow and state Treasurer John Fleming advanced to a June runoff to choose the party's nominee after a closely fought three-way battle.
Cassidy, a physician who first earned the president's ire by voting for his conviction in Trump's second Senate impeachment trial in 2021, was projected to finish in third place in a political victory for Trump's retribution campaign that recently unseated several Republican senators in Indiana who defied his push for state congressional re-districting.
He is the first elected U.S. senator to lose re-nomination since 2012.
Letlow, who won Trump's Senate endorsement before she had even announced her candidacy, led Fleming 45.2% to 28.3% with 98% of votes counted, the Associated Press reported.
The two candidates will now face each other in a June 27 run-off election to determine which candidate will confront Democrat Jamie Davis, who was projected to win his party's nomination, in the November general election.
The winner of the runoff is likely to fill the seat, according to independent analysts who rate Louisiana as solidly Republican.
"THANK YOU, LOUISIANA! Louisiana made it clear tonight: we are ready for strong conservative leadership that will stand with President Trump and never waver. Because of your support, your prayers, and your belief in this campaign, we are one step closer to sending that leadership to the United States Senate," Letlow said in a post on X.
Trump congratulated and praised Letlow on social media while gloating about Cassidy's loss. "His disloyalty to the man who got him elected is now a part of legend, and it’s nice to see that his political career is OVER!" Trump said in a lengthy post on Saturday night.
In his concession speech, Cassidy thanked his supporters for allowing him to represent Louisiana for 12 years.
"When you participate in democracy, sometimes it doesn't turn out the way you want it to. But you don't pout. You don't whine. You thank the voters for the privilege of representing the state or the country for as long as you've had that privilege," Cassidy said.
TRUMP RETRIBUTION CAMPAIGN
The Louisiana primary was the latest venue for an ongoing Trump retribution campaign that delivered primary defeats this month against at least five of seven Republican state legislators in Indiana, who opposed the president's push for a mid-decade congressional redistricting plan to protect the Republican majority in the U.S. House of Representatives.
Next week, Trump's campaign moves to Kentucky, where the president hopes to see his hand-picked primary challenger Ed Gallrein defeat Republican U.S. Representative Thomas Massie, a Trump critic and leading voice in the campaign to release government files on convicted sex offender Jeffrey Epstein, an erstwhile friend of the president.
Letlow, 45, entered Congress when her husband Luke died of a COVID infection after being elected to the House in 2020. She ran to replace him in a special election and succeeded with Trump's endorsement.
Cassidy had targeted her support for diversity, equity and inclusion initiatives when she worked for the University of Louisiana at Monroe. She responded with ads calling Cassidy and Fleming "Never Trumpers" and emphasizing her presidential endorsement.
Cassidy, a 68-year-old doctor who specialized in the treatment of liver disease and helped found a Baton Rouge clinic that serves low-income patients, served in the Louisiana Senate and the U.S. House before unseating former Democratic U.S. Senator Mary Landrieu in 2014 to become the first Republican to capture the seat since 1883.
He now chairs the Senate Health, Education, Labor and Pensions Committee. He was re-elected in 2020 with nearly 60% of the vote.
CASSIDY VOTED TO IMPEACH TRUMP
Cassidy had a series of conflicts with Trump beginning with his role in 2021 as one of seven Republicans who supported Trump's impeachment after the January 6 attack on the U.S. Capitol by Trump supporters. He is now one of only three still in office.
Cassidy later called on Trump to drop out of the 2024 presidential race after his indictment for allegedly mishandling classified documents and declined to endorse Trump after he won the Republican nomination.
Since Trump's return to the White House, Cassidy has tried to work his way back into the president's good graces by supporting Robert F. Kennedy Jr.'s nomination for U.S. health secretary.
But Cassidy's support for Trump health policy has been short-lived, with him expressing open skepticism for Kennedy's bid to overhaul U.S. vaccine policy and joining fellow Republican Senators Susan Collins and Lisa Murkowski to slow the health secretary's agenda in Congress.
The most recent break came last month when Trump accused Cassidy of blocking the nomination of Casey Means as U.S. surgeon general, forcing the president to name radiologist and Fox News contributor Nicole Saphier as his third pick for the job.
Former Republican Senator Richard Lugar was the last elected incumbent to lose his bid for re-nomination in 2012.
(Reporting by David Morgan. Additional reporting by Christian Martinez, Marcelo Teixeira, David Hood-Nuño and Blake Brittain. Editing by Michael Learmonth, Alistair Bell, Mark Potter and Raju Gopalakrishnan)




