Welcome to a special edition of At the Races! Throughout the 2026 primary season, watch for these updates from the CQ Roll Call campaign team on what you need to know for election day. Know someone who’d like to get this newsletter? They can subscribe here.

By Daniela Altimari and Mary Ellen McIntire

Texas Sen. John Cornyn’s bid for renomination in the Republican primary was a challenge from the start, but it grew exponentially tougher last week, when President Donald Trump endorsed state Attorney General Ken Paxton.

Less than two days before Tuesday’s Republican runoff, Trump reiterated his support for Paxton in a social media post, calling him a “GREAT Attorney General” who was “very loyal to your favorite President, ME.”

The contest between Cornyn and Paxton has been among the cycle’s nastiest, with the senator running ads accusing his opponent of financial impropriety, ethical lapses and moral failings. Paxton, a Trump-style political disrupter, has portrayed Cornyn as insufficiently loyal to the president, out of step with the party’s MAGA base and too willing to compromise with Democrats.