Bill Cassidy

Bill Cassidy is a physician by training who served as Louisiana's US Senator from 2015 until his defeat in the 2026 Republican primary. He sat on the Senate Finance Committee and the Health, Education, Labour and Pensions Committee, and was one of seven Republicans to vote to convict Donald Trump in the February 2021 impeachment trial, a vote that shaped his reputation as an occasional bipartisan dissenter.

That reputation carried into 2026. On 19 May Cassidy became the decisive fourth crossover vote when a Senate Foreign Relations Committee discharge motion cleared 50-47, placing the Kaine Iran war-powers resolution on the floor calendar; it was his first crossing on any Iran legislative instrument. The measure ultimately stalled roughly ten votes short of the 60 needed for cloture after the House passed its own version 215-208 on 3 June.

The independence cost him his seat. Cassidy finished third with 24.8% in Louisiana's 17 May primary, behind Trump-endorsed Julia Letlow (44.8%) and state treasurer John Fleming (28.3%), becoming the first elected incumbent senator to lose renomination since Richard Lugar in 2012. Letlow went on to beat Fleming 56.8% to 43.2% in the 27 June runoff, a wider margin than late polling suggested, ending Cassidy's Senate career and shifting the seat further right regardless of the outcome.