Cornyn and Paxton go head-to-head in Texas Republican Senate primary after Trump endorsement

The winner of the Republican runoff will face off against Democratic state legislator James Talarico in the general election in November. The race is expected to be one of the most expensive in the nation as the GOP vies to keep control of the Senate and Democrats push to win a long-sought Senate seat in Texas.

Cornyn came out narrowly on top of Paxton in the March primary, but failed to garner enough votes to avoid a runoff.

Trump’s endorsement of Paxton last week sent shockwaves through the Republican-controlled Senate, which has poured significant resources into Cornyn’s reelection bid. Cornyn also took extensive steps to mend his relationship with Trump, which has been strained over the years.

The Republican primary in Texas has been among the messiest of the 2026 campaign cycle. Cornyn’s campaign has slammed Paxton, a close Trump ally, over a slew of ethical and legal scandals that have plagued him and his office throughout his tenure as the Lone Star State’s top law enforcement official.

Paxton was impeached by the Texas House of Representatives and acquitted by the Senate and has been indicted for securities fraud. He was recently divorced from his wife on what she described as “biblical grounds.”

Paxton’s campaign, meanwhile, has tried to frame Cornyn as a longtime Washington establishment figure.

Cornyn is a four-term incumbent with significant cachet in the Senate. He was the Senate Republican Whip, the no. 2 position in the upper chamber, from 2013-2019. He lost a 2024 bid to lead Republicans in the Senate to Senate Majority Leader John Thune, but is still popular with his colleagues. Senate Republicans believe Cornyn would be a more formidable —and less expensive — opponent to Talarico in the general election.

Paxton is the odds-on favorite to come out on top in the primary after the Trump endorsement. A Quantus Insights poll released on Monday found Paxton leading Cornyn by 9.3 percentage points heading into Election Day.

Trump has made vanquishing his political enemies in the GOP a priority in his second term. Sen. Bill Cassidy, R-La., failed to qualify for a runoff in Louisiana earlier in May after Trump endorsed his opponent in the primary. And Rep. Thomas Massie, R-Ky., a frequent Trump foil in his second term, fell in a primary to Trump-backed challenger Ed Gallrein.

In endorsing Paxton on Truth Social, Trump said Cornyn is “a good man, and I worked well with him, but he was not supportive of me when times were tough.”

“Ken Paxton has gone through a lot, in many cases, very unfairly, but he is a Fighter, and knows how to WIN,” the president said. “Our Country needs Fighters, and also Loyalty to the Cause of Greatness.”