Texas Attorney General Ken Paxton defeated Sen. John Cornyn (R-TX) in Tuesday’s Republican Senate primary runoff. The victory marked a major win for President Donald Trump-backed candidates ahead of the 2026 midterm elections.
Paxton defeated Cornyn by a wide margin after securing Trump’s endorsement just one week before the runoff. With nearly half the vote counted when the race was called, Paxton led 62.5% to 37.5%, according to the Associated Press.
The victory ends Cornyn’s bid for a fifth Senate term. It also marks one of the biggest Republican primary upsets of the 2026 cycle.
Cornyn had served in the Senate for more than two decades. He was backed by many GOP establishment figures, including Senate Majority Leader John Thune (R-SD) and the National Republican Senatorial Committee.
Paxton’s win came after Trump gave him his “Complete and Total Endorsement.” Trump called the Texas attorney general an “America First Patriot” and praised his support for border security, election integrity, oil and gas production, and Second Amendment rights.
Trump also criticized Cornyn for being “very late” in supporting his presidential campaign. He suggested Paxton would better advance the MAGA agenda in Washington.
After the race was called, Paxton praised Trump during his victory speech. He called the president’s endorsement “the most powerful force in politics.”
“When everyone in Washington told him to abandon me and abandon the people of Texas he didn’t listen,” Paxton said. “Instead, he gave his complete and total endorsement.”
Paxton will now face Democrat James Talarico in the November general election. Talarico is a state representative and former teacher who won the Democratic nomination earlier this year.
The Texas race is expected to play a major role in determining whether Republicans maintain control of the Senate. A recent Texas Southern University and YouGov poll showed Paxton and Talarico tied at 45% each.
During the primary battle, Cornyn argued that he had consistently supported Trump’s agenda in the Senate. He pointed to his role in confirming conservative judges and advancing Republican tax legislation.
Despite the heated campaign, Cornyn said in his concession speech that he would support Paxton in the general election.
“I’ve said throughout this race that I trust the voters of Texas, and they’ve made their decision, and I respect it,” Cornyn said.
Paxton has long been a controversial figure in Texas politics. He survived an impeachment trial in 2023 after facing allegations that included abuse of office and misuse of public resources. He was also previously indicted on securities fraud charges that were later dismissed.
The Texas Senate primary became the most expensive Senate primary race in U.S. history. More than $110 million was spent on advertising, according to AdImpact. More than $64 million of that total went toward ads supporting Cornyn.