John Cornyn’s loss in the May 2026 Republican primary runoff to Ken Paxton, sealed by a late Donald Trump endorsement, has left the former incumbent publicly critical of his successor. Recent statements in September 2026, including refusals to fundraise or campaign for Paxton and descriptions of him as flawed, have reinforced trader views that Cornyn will withhold a formal endorsement in the general election matchup against Democrat James Talarico. Talarico has signaled openness to Cornyn’s support, yet no such move has occurred. The combination of primary bitterness, Cornyn’s establishment positioning, and absence of any announcement sustains the dominant market probability on no endorsement, with limited upside priced for either major-party nominee.