John Cornyn’s (R-Tex.) primary loss to Ken Paxton (R) on May 26 is the first instance of a fourth-term senator losing re-election in the 21st century. Since 2000, only five senators who served three or more terms, including Cornyn, have lost their primary bids for re-election, including Joe Lieberman (I-Conn.), who went on to win a third-party campaign. Overall, 16 senators running for a fourth term or higher have lost re-election bids since 2000.
Of the sixteen senators, nine were Democratic senators, and seven were Republicans. Eleven lost bids for a fourth term, two lost bids for a sixth term, and one each lost bids for a fifth term and a seventh term. The longest-serving senator to be defeated at this time was Richard Lugar (R-Ind.), who lost his re-nomination bid for a seventh term. The longest-serving senator to lose a general election in this time was William Roth (R-Del.), who, in his campaign for a sixth term, was defeated by Tom Carper (D-Del.) in 2000. The year with the most defeated multi-term senators was 2010 and 2024, when three senators each lost re-election.
