Senator Bill Cassidy lost his Louisiana Republican primary on Saturday, another victim of President Donald Trump's campaign to punish party members who crossed him. Cassidy, who voted to convict Trump after the January 6, 2021 Capitol attack, finished behind Trump-endorsed Representative Julia Letlow and state Treasurer John Fleming. Trump celebrated the loss, calling Cassidy's vote "disloyalty" that would become "a part of legend."

The ouster of Cassidy follows a string of victories for Trump's retribution tour. Five Trump-backed challengers unseated Indiana state lawmakers who refused to redraw the state's congressional map. Now Trump is targeting Thomas Massie of Kentucky, a longtime critic who accused the president of violating campaign promises by launching the war with Iran. Trump has endorsed Ed Gallrein against Massie in a Tuesday primary.

The results reveal a party wrestling with midterm headwinds—high consumer prices, an unpopular Iran war, and Trump's underwater approval rating. Yet his grip on Republican primary voters remains ironclad. Strategist Scott Jennings put it bluntly: "Donald Trump's word and judgment in a Republican primary is the thing that matters the most." For vulnerable Republicans, dissent carries a steep political price.