Republican Bill Cassidy of Louisiana became the first incumbent senator since 2012 to lose a primary, falling to Trump-endorsed challenger Julia Letlow and John Fleming.
Neither Letlow nor Fleming received 50% of the vote and will move on to a runoff in June.
JUST IN: Two Republican challengers, Rep. Julia Letlow and state Treasurer John Fleming, will advance to a runoff election in Louisiana's closely watched GOP primary, the Associated Press projected. https://t.co/M6sW2qz11i pic.twitter.com/OS0NxsYWhN
— ABC News (@ABC) May 17, 2026
Cassidy had made himself a political enemy of President Trump when he voted to convict him in his impeachment trial in 2020. Siding with the Democrats came back to haunt him.
The President made clear, on a Truth Social post, that he did not forget, nor forgive, the RINO Senator's disloyal action.
𝗗𝗼𝗻𝗮𝗹𝗱 𝗝. 𝗧𝗿𝘂𝗺𝗽 𝗧𝗿𝘂𝘁𝗵 𝗦𝗼𝗰𝗶𝗮𝗹 𝟱.𝟭𝟲.𝟮𝟲 𝟭𝟬:𝟱𝟮 𝗣𝗠 𝗘𝗦𝗧
— Commentary Donald J. Trump Posts From Truth Social (@TrumpDailyPosts) May 17, 2026
Bill Cassidy, after falsely using his “relationship” with me during his political career, and winning Elections because of it, voted to impeach me on preposterous charges that were fake then,…
The President's entire post:
Bill Cassidy, after falsely using his “relationship” with me during his political career, and winning Elections because of it, voted to impeach me on preposterous charges that were fake then, and now, are criminally insane! 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! I’d like to thank the Great People of the State of Louisiana, and this Big Victory will only make me work even harder for your success, and all that comes with it. I LOVE YOU ALL. MAKE AMERICA GREAT AGAIN! President DONALD J. TRUMP
He also took time to congratulate and reaffirm his endorsement of Julia Letlow.
Congratulations to Congresswoman Julia Letlow on a fantastic race, beating an Incumbent Senator by Record Setting Numbers. This is the first time in History that a sitting Senator has lost by such large numbers in a Primary, unable to even go forward. Julia Letlow is a fantastic… pic.twitter.com/XdmsWwHdxs
— Donald J Trump Truth Social Posts On X (@TrumpTruthOnX) May 17, 2026
As for Cassidy, the primary defeat will end his political career, but not necessarily his career in politics.
LMAO at the “MAgA Is dEAd” crowd.
— Gunther Eagleman™ (@GuntherEagleman) May 17, 2026
Bill Cassidy thought it was and now his next stop is the unemployment line.
Don’t worry, Bill Cassidy will make a seamless transition into a Big Pharma lobbyist.
— Vadim Bichutskiy (@VadimBichutskiy) May 17, 2026
That's sadly true. There will be plenty of room in the swamp for him if he chooses to keep swimming after his term ends at the end of the year.
Bill Cassidy has been primaried in Louisiana.
— Andrew Alvarez (@theOGalv) May 17, 2026
Another Senate RINO feeling the heat from conservatives.
The Senate is cleaning itself out. Let’s keep this going.
IT’S OFFICIAL
— ThePersistence (@ScottPresler) May 17, 2026
Incumbent Senator Bill Cassidy has been DEFEATED after coming in 3rd place.
Cassidy voted to convict President Trump, voted for red flag laws, & voted for Senate Majority Leader Thune.
Louisiana will elect a new Senator this November. pic.twitter.com/bYzpzX2MaA
Hahaha! pic.twitter.com/n30ZGABua3
— MAGA QUEEN (@JoannaRN_) May 17, 2026
Back in 2020, Cassidy had said that he voted his conscience. Last night, Republicans in Louisiana voted theirs.