In a seismic shake-up for Republican politics, Texas Attorney General Ken Paxton has defeated four-term incumbent Sen. John Cornyn in the GOP Senate primary runoff held on May 26, 2026. NBC News, CBS News, CNN, and the Associated Press all projected Paxton as the winner, making him the Republican nominee for the U.S. Senate seat from Texas heading into the November general election.
The Result: A Historic Upset
Paxton’s victory marks a historic moment in Texas politics. With results showing Paxton capturing approximately 62% of the vote to Cornyn’s 38%, the win was decisive — and it comes with enormous significance. Cornyn, who has served in the U.S. Senate since 2002, becomes the first Republican senator from Texas ever to lose his party’s nomination for reelection.
The runoff was triggered after neither candidate secured more than 50% of the vote in the initial multicandidate March 3, 2026 primary, where Cornyn led Paxton narrowly with 42% to Paxton’s 40.5%, with U.S. Rep. Wesley Hunt finishing third at 13.5%.
Trump’s Late Endorsement Was the Game-Changer
Perhaps no single factor loomed larger in the outcome than a last-minute endorsement from President Donald Trump. Trump backed Paxton just days before the runoff — a move that many analysts and Paxton himself credited as decisive.
“I’ve never seen an endorsement matter more since I’ve been paying attention to politics,” Paxton said on The Clay Travis & Buck Sexton Show on election day, calling Trump’s endorsement the “gold standard.”
Trump’s decision came after polling showed Paxton ahead in the runoff. While Trump had previously signaled that either candidate could defeat Democrat James Talarico in November, he ultimately chose Paxton, citing Cornyn’s insufficient loyalty at key moments. Trump pointed to the fact that Cornyn had stayed neutral in the 2016 GOP presidential primary and had said in 2023 that Trump’s “time has passed him by” — comments Cornyn later walked back when he endorsed Trump for his second term.
The Most Expensive Senate Primary in History
The road to this runoff was extraordinarily expensive. The 2026 Republican primary for the U.S. Senate in Texas was already the most expensive on record by the end of its first round, and the runoff pushed total advertising spending to just under $130 million — a staggering sum that drained Republican coffers nationwide.
Cornyn and his allies significantly outspent Paxton throughout the contest. In the runoff alone, pro-Cornyn advertising totaled approximately $23 million, compared to roughly $7 million on the Paxton side. Over the entire primary campaign, Cornyn and his backers spent more than $90 million combined, while Paxton and his supporters combined for about $15 million — making Paxton’s victory even more stunning given the financial disparity.
Paxton’s Path to the Nomination
Throughout the campaign, Ken Paxton positioned himself as the true MAGA candidate — a loyal ally of Trump and a fierce fighter for conservative Texas values. He relentlessly attacked Cornyn for his history of working across the aisle with Democrats, criticized him for past comments about Trump, and highlighted moments where he felt Cornyn had failed to fully back the former and current president.
Paxton notably led a lawsuit challenging the 2020 election results, a move he repeatedly invoked as proof of his loyalty to Trump. He emphasized his record as Texas Attorney General in pushing back against federal overreach, defending gun rights, securing the border, and fighting liberal policy initiatives.
Cornyn, for his part, tried to paint Paxton as a liability — “a flawed, self-centered, and shameless candidate” who would, in Cornyn’s words, be “a dead weight at the top of the ticket for Republicans.” Cornyn also had the backing of Senate Republican leadership and outspent Paxton by a massive margin.
In the end, it was not enough.
What Cornyn Said After His Loss
In remarks after his projected loss, Cornyn was gracious but reflective. “Serving others is a high purpose and while much about politics is ugly, we choose to serve through the good, the bad, and the ugly,” he told reporters. Cornyn said he respects the decision of Texas voters, ending one of the longest-serving Republican Senate tenures in the state’s history.
The Road Ahead: Paxton vs. Talarico in November
Ken Paxton will now face Democratic state Rep. James Talarico in the November 2026 general election — a race that could be pivotal in the broader fight for control of the U.S. Senate.
Talarico, an Austin state representative, former schoolteacher, and Presbyterian seminarian, won the Democratic Senate primary on March 3, 2026, defeating U.S. Rep. Jasmine Crockett with 53% of the vote. He is a progressive, energetic candidate who has energized the Texas Democratic base.
The general election matchup is shaping up to be one of the most closely watched Senate races of the 2026 midterm cycle. A Democrat has not won a statewide race in Texas since 1994, and has not won a U.S. Senate seat in the state since 1988. However, pre-election polling had shown Talarico performing slightly better in a hypothetical matchup against Paxton than against Cornyn, raising Democratic hopes.
Some Republican strategists have warned that nominating Paxton — a conservative firebrand who has faced multiple controversies over the years — could cost the party millions of additional dollars to defend what should be a safe red-state seat. Democrats need a net gain of four Senate seats to reclaim the majority, and Texas, while still a longshot, is now firmly on their target list.
Paxton and his allied super PAC, Lone Star Liberty PAC, are already gearing up for the general election fight, working to consolidate Cornyn’s former supporters, court conservative voters who sat out the primary, and win over independents.
A Pattern of Trump Reshaping the Republican Party
Paxton’s victory is part of a broader pattern in the 2026 midterm cycle of Trump successfully backing primary challengers against Republicans he views as insufficiently loyal. In the weeks around this race, Trump-backed opponents also defeated Rep. Thomas Massie of Kentucky, Sen. Bill Cassidy of Louisiana, and several Indiana state senators. The Texas result, however, is arguably the highest-profile scalp yet — the toppling of a four-term U.S. senator and a former Senate Republican Whip.
Key Takeaways
- Ken Paxton wins the Texas GOP Senate primary runoff with approximately 62% of the vote.
- John Cornyn becomes the first Republican Texas senator ever to lose a reelection primary.
- Trump’s late endorsement of Paxton is widely credited as the decisive factor.
- The race is the most expensive Senate primary in U.S. history, with nearly $130 million in total advertising spend.
- Paxton will face Democrat James Talarico in November in what could be a nationally significant Senate contest.
- A Democratic win in Texas would be the first U.S. Senate victory in the state for the party since 1988.
The biggest political story out of Texas in decades is just beginning — drop your thoughts in the comments below and stay tuned as the Paxton vs. Talarico Senate race heats up heading into November 2026.