Bill Cassidy, Louisiana's two-term Republican senator who voted to convict Donald Trump in the February 2021 impeachment trial, finished third in the 16 May primary with 24.8%, behind Trump-endorsed Julia Letlow at 44.8% and state treasurer John Fleming at 28.3%1. Cassidy became the first elected incumbent senator to lose renomination since Richard Lugar of Indiana in 2012. Letlow and Fleming advance to a 27 June runoff2.
The seat shifts further right regardless of which candidate wins. Letlow, whom Trump endorsed in January, leads; Fleming is a former congressman whose positions align closely with the MAGA flank. Neither resembles Cassidy, who had sustained a working relationship with Democratic colleagues on infrastructure and Medicaid policy. The outcome of the runoff determines the degree of rightward shift, not its direction. Louisiana is a solidly Republican state in federal contests, so the general election is not a competitive concern for Republicans; the NRSC will not need to defend it the way it must now defend Texas.
Cassidy's elimination forms a clear pattern with the Cornyn result, both within a cycle in which Cook moved four Senate races toward Democrats in a single week: two sitting Republican senators who maintained institutional independence or broke with Trump on specific votes lost renomination to challengers backed by the MAGA base. Lugar's 2012 loss to Richard Mourdock remains the most instructive historical parallel; Mourdock then made a controversial remark on pregnancy and rape and lost a winnable Indiana seat in November, showing that primary-driven candidate selection in a wave environment carries its own general-election risk. Louisiana's structural Republican tilt reduces that risk considerably; Texas does not offer the same insulation.
