Trump-backed Paxton defeats Cornyn in costly Texas Senate runoff

Ken Paxton’s defeat of John Cornyn in the Texas Republican Senate runoff marked another hard-edged demonstration of Donald Trump’s control over the GOP, and a punishing warning for senators who believe loyalty alone can shield them from a primary challenge. Trump endorsed Paxton last week, and the race was projected the same night on Tuesday, May 26, 2026.

Cornyn’s loss carried historic weight in Texas. He became the first Republican senator from the state to lose the party’s nomination for reelection, ending a four-term Senate tenure that had been defined in part by an extended effort to prove himself to Trump and to the party’s activist base. Cornyn spent months telling voters he backed Trump 99% of the time, but Trump ultimately sided with Paxton, calling him a “true MAGA Warrior” and saying Cornyn was “VERY disloyal to me.”

The runoff was the product of a fractured March 3 primary in which no candidate secured an outright majority, forcing Texas Republicans into a second round that deepened the party’s internal split. Paxton’s victory also sharpened a long-running Texas feud that has included years of controversy around the attorney general, impeachment battles, and a broader clash between the state party’s old guard and its insurgent MAGA wing.

The financial scale underscored how much was at stake. Reporting put advertising spending at nearly $100 million by mid-February and more than $120 million across both rounds of the race, including about $21 million in the runoff alone. That made the contest one of the most expensive Senate primaries in American history, a sign that the fight over Texas Republican identity had moved far beyond a routine intraparty contest.

Paxton will now face Democratic state Rep. James Talarico in November. The general election still begins with Texas’ deep Republican advantage: Democrats have not won statewide in the state since 1994 and have not won a U.S. Senate race there since 1988. Even so, the runoff raised a larger question for the party’s next Senate map: whether Republican incumbents in red states now fear a primary electorate, and Trump’s approval, more than the general election itself.