Louisiana two-term U.S. Senator Bill Cassidy (R) lost the Republican primary on May 16, 2026, finishing third with about 24% to 25% of the vote and not advancing to the June 27 runoff. The primary set up a runoff between Trump-backed U.S. Representative Julia Letlow, who won about 45%, and state Treasurer John Fleming, who earned about 28%.
Politico reports Cassidy’s defeat is historically notable, as he is the first previously elected, sitting senator from either political party to lose a primary reelection bid since 2012. Media and analysts point to the backlash over Cassidy’s 2021 decision to vote to convict Donald Trump during the second impeachment trial after January 6, with Trump targeting Cassidy during the 2026 cycle.