Thune endorses Cornyn as Paxton eyes Texas primary challenge

Senate Majority Leader John Thune (R-S.D.) has endorsed Texas Sen. John Cornyn’s (R) reelection bid as state Attorney General Ken Paxton (R) eyes challenging the longtime incumbent in next year’s primary.

“I’ve been honored to work alongside @JohnCornyn—one of the most effective and respected conservative leaders in the country. He was tireless and instrumental in building our majority,” Thune wrote on the social platform X in response to Cornyn’s reelection campaign launch. 

“We need to keep him in the Senate & in the fight to deliver on President Trump’s agenda.”

A handful of other GOP figures weighed in with support, including Sen. Steve Daines (Mont.), last cycle’s National Republican Senatorial Committee (NRSC) chair, who also argued that Republicans “need” Cornyn in the Senate.

Cornyn’s race is among several in the 2026 midterms where incumbent Republicans are bracing for potentially tough primary challenges from the MAGA faction of the party.

Paxton hasn’t formally launched a campaign, but speculation has long swirled that the conservative firebrand could make a jump for the Senate. He's recently hinted at a run, telling Punchbowl News this month that Cornyn, who is seeking his fifth term, has “had his chance.” 

If Paxton does jump in the race, it would spotlight the ongoing friction within the Texas Republican Party between the establishment wing, represented by Cornyn, and an ascendant far-right wing. 

Cornyn has held his Senate seat for more than two decades, but Paxton, who's served as state attorney general since 2015, has seen his national profile rise in recent years. In 2023, he was impeached by the Texas House on corruption allegations, but was later acquitted and reinstated by the state Senate.

Polls tracked by the Texas Politics Project at the University of Texas at Austin put Cornyn's job approval at around 49 percent, while Paxton boasts 62 percent approval.