Trump’s Pick Paxton Defeats Cornyn in Texas Primary: A Turning Point for the GOP

Ken Paxton’s decisive win over four‑term Senator John Cornyn underscores Trump’s sway—and raises high‑stakes questions for November

Texas Attorney General Ken Paxton, buoyed by a last‑minute endorsement from former President Trump, soundly defeated incumbent Senator John Cornyn in the Republican primary runoff on May 26, 2026. Paxton’s 28‑point margin—the largest primary loss for a sitting senator in nearly half a century—signals Trump’s continued dominance within the GOP while heightening concerns about general election viability and party unity.

A Historic Upset and Trump’s Final Word

On May 26, 2026, Texas Attorney General Ken Paxton routed four‑term Senator John Cornyn in the Republican U.S. Senate primary runoff, capturing approximately 62.5% of the vote to Cornyn’s 37.5%, according to early returns . The Associated Press called the race shortly after 8 p.m. Central Time, marking the first defeat of a sitting U.S. senator in a primary since 1970 in Texas . Trump’s endorsement, issued just a week before the runoff, proved decisive. He hailed Paxton as “a true MAGA Warrior” and criticized Cornyn for his delayed support in 2024, delivering a powerful late boost that reverberated across the state and Washington alike .

Money, Momentum, and Runoff Dynamics

Despite being heavily outraised—Cornyn’s campaign and allies outspent Paxton by nearly nine‑to‑one overall and over three‑to‑one in the runoff—the runoff’s low‑turnout, highly partisan electorate favored Paxton’s base support and Trump’s surge . Early polling had shown a tight race: a May 2–5 survey had Cornyn leading 47% to 46%, with a 3% margin of error . Meanwhile, a Forbes‑cited result showed Paxton at 62.5% post‑call, highlighting the volatility of runoff contests .