Texas Attorney General Ken Paxton defeated incumbent U.S. Senator John Cornyn in the Republican primary runoff on Tuesday night, March 5, 2026.
The victory marks a significant shift in the state's political landscape by replacing a long-term incumbent with a candidate backed by Donald Trump. This outcome reflects the growing influence of the former president over the Republican nomination process in Texas.
Paxton secured the party's nomination after Cornyn failed to win a majority during the initial March primary. This failure forced the runoff election that ultimately led to the incumbent's defeat. The result makes Cornyn the first Texas Republican senator to lose renomination [2].
Cornyn had served four terms as U.S. Senator [1]. His tenure ended after Paxton leveraged a decisive boost from an endorsement by Donald Trump to win over the primary electorate. The campaign focused on the party's direction, and alignment with the Trump wing of the GOP.
The runoff occurred across Texas, finalizing the Republican ticket for the U.S. Senate seat. Paxton now moves forward as the official nominee for the general election, having successfully challenged the established party leadership in the state.
“Ken Paxton defeated incumbent U.S. Senator John Cornyn in the Republican primary runoff”
The defeat of a four-term incumbent by a Trump-endorsed challenger signals a consolidation of the populist wing within the Texas Republican Party. By removing an established figure like Cornyn, the party is moving toward a more aggressive alignment with Donald Trump's political priorities, potentially altering the legislative approach of the Texas delegation in Washington.
