Texas Attorney General Ken Paxton’s attempt to topple Republican Sen. John Cornyn in a Senate primary next year kicks off one of the most intense contests of the 2026 elections — a GOP-versus-GOP battle between two men who have been sparring for years and vying for President Donald Trump’s attention.
Cornyn is a fixture of the Republican Party in Texas, serving in its highest offices for more than 30 years and becoming a key voice on Capitol Hill. Paxton, the third-term attorney general who survived a bipartisan impeachment last year in part thanks to support from Trump and conservative activist allies, believes there’s an opening to cut the incumbent down from the right.
Now, both sides are aligning themselves with Trump amid the possibility of an endorsement that could tip the primary.
Whether one comes or not, one thing is clear. “This is gonna be the nastiest race in the modern era of Texas politics, period,” former Travis County GOP chairman Matt Mackowiak said.
Paxton immediately attacked Cornyn for having “turned his back on President Trump,” pointing to comments Cornyn made in 2023 about Trump’s indictment over his handling of classified documents, as well as the senator’s comments that he didn’t think Trump “could win the presidency” after Trump was found liable for sexual abuse in a civil case that same year.
Paxton has also targeted Cornyn over his votes on issues including guns and immigration to try to argue that he is more aligned with conservative values.
“While John was criticizing Trump and suggesting he shouldn’t run, I was at Mar-a-Lago” for Trump’s presidential announcement speech, Paxton told “The Mark Davis Show” in Dallas.
"If he had the record of [Texas GOP Sen.] Ted Cruz, would I be here? Absolutely not," Paxton continued. "This isn’t about what he’s saying and the love he suddenly has for President Trump and the love he has for all of our issues now. This isn’t about that love. I don’t believe that love, I believe in action."
Cornyn, though, also made an appeal to Trump’s interests, telling reporters at the Capitol on Wednesday that Paxton’s Senate bid is a “con man’s vanity project.”
“The biggest potential loser is President Trump’s agenda,” Cornyn said of the primary challenge.
“Mr. Paxton has a checkered background, he is a con man and a fraud, and I think the people of Texas know that, but this is what will be litigated during the course of this campaign. I am not going to turn over the Senate seat that was once held by Sam Houston to someone like him,” he added, a reference to the 2023 impeachment trial of Paxton, after which he survived a conviction vote in the state Senate.
“It’s unclear to me exactly what is motivating Mr. Paxton other than vanity and personal ambition,” Cornyn continued.
In the months before Paxton jumped in — and in the hours since — Cornyn has made clear he’s hugging Trump as tight as he can. He posted on X a photo of him reading Trump’s “The Art of the Deal” and called it “recommended” reading; he took to the Senate floor to defend Trump aide and billionaire Elon Musk (whose businesses have a significant footprint in Texas) after protests at Tesla dealerships; and he has been framing himself as one of Trump’s top allies in the Senate.
A long-simmering feud
The roots of this clash between another establishment-insurgent pair of Republicans run deep, part of a decade-plus battle within the Texas GOP that has ousted legislative leaders, fueled Cruz's rise, fanned the flames of Paxton’s impeachment, and led to proxy wars up and down the ballot.
Paxton had been telegraphing a run against Cornyn from the right for more than a year. In early 2024, Paxton lambasted the senator as “anti-Trump [and] anti-gun” in a post on X, adding that “Texans deserve another conservative Senator.”
Cornyn reposted the message and replied: “Hard to run from prison, Ken,” a reference to the investigations that led to the impeachment trial. (The Associated Press reported this month that the Justice Department decided last year not to prosecute Paxton over corruption allegations.)
Brendan Steinhauser, a longtime GOP consultant who served as Cornyn’s campaign manager in the past but is unaffiliated in this race, told NBC News it’s no surprise to see Cornyn campaign with an eye on Trump.
“If you’re Senator Cornyn, you’re going to be campaigning on all the ways that you have supported and worked with the president, you’re going to talk about all the policies where you align, you’re going to talk about helping to get all of his judicial nominees through,” he said.
While a potential endorsement from Trump remains a major question, Cornyn does have support from Senate Republicans. Sen. Tim Scott, of South Carolina, who chairs the National Republican Senatorial Committee, has made his case for Cornyn to White House officials.
Scott also told Rep. Wesley Hunt, R-Texas, who has also been weighing a Senate run, that the NRSC is behind Cornyn, according to a source familiar with the discussions.
“John Cornyn is a leader who delivers on President Trump’s agenda and for the people of Texas in the U.S. Senate,” Scott said in a statement to NBC News. “He’s a proven fighter, man of faith and essential part of the Republican Senate Majority.”
Senate Majority Leader John Thune, R-S.D., has also been publicly backing Cornyn and recently told CNN he was hopeful Trump would back Cornyn in the race.
Asked Wednesday if he has personally asked Trump to endorse Cornyn, Thune told reporters at the Capitol: “Well, we’re having conversations about all of the races on the map. When we have anything to report, we’ll let you know.”
Senate Leadership Fund, the main GOP super PAC involved in Senate races, which is aligned with Republican leadership, indicated it is also in Cornyn's corner.
"Leader John Thune, NRSC Chairman Tim Scott, and many of their colleagues have expressed great admiration and support for Senator John Cornyn and his years of service to the people of Texas," SLF Chairman Cory Gardner, a former senator from Colorado, said in a statement to NBC News. "The Senate Leadership Fund fully intends on seeing him reelected next November."
Mackowiak, a longtime Texas political consultant, told NBC News that he sees Paxton’s early announcement as an indication of two things: The attorney general sees an opening, but he knows he needs time to raise the money required to combat Cornyn and the power of incumbency.
“Paxton’s never run a race this complicated, this expensive against someone as accomplished and serious as John Cornyn," he said. "John Cornyn has never been challenged by someone that has the statewide profile and grassroots enthusiasm Paxton has."
But Mackowiak argued that while Paxton has sought to go on offense early, that dynamic may not stick, and that the events that led to Paxton’s impeachment trial (which divided Republicans in the state) will likely be relitigated.
“He is going to be playing a lot more defense than he even understands. I think because he got through impeachment, these issues are behind him. They’re not,” he said.
One potential wrinkle, particularly if Hunt or another Republican decides to jump in, is Texas’ runoff rules. If no candidate wins the majority of the vote in the primary, the top two move on to a one-on-one runoff election.
Cornyn has never lost an election in Texas, and he’s never been forced to a runoff by any of his opponents (who have largely challenged him from the right). But the prospect of a split field leading to a runoff is another complicating factor, with both Mackowiak and Steinhauser noting that runoff electorates typically favor the candidate with more grassroots conservative support.
Senate map
The Texas race could have broader implications for the fight for the Senate next year as Republicans look to defend their slim majority.
Democrats need to net three seats to take control of the Senate, but they face an uphill battle with a short list of targets. Just one Republican — Maine’s Susan Collins — is running in a state that former Vice President Kamala Harris carried in November. Republicans, meanwhile, are looking to grow their majority by targeting Democratic-held seats in battleground states.
But Cornyn said a competitive election in Texas could put a strain on Republicans nationally by diverting money away from other key battlegrounds.
“We’re going to end up spending hundreds of millions of dollars, potentially, on this race in Texas, because we can’t lose the seat in Texas,” said Cornyn, a former NRSC chairman. “And that is money that can’t be used in places like Michigan, New Hampshire and Georgia in the midterm elections.”
Democrats have long coveted the idea of flipping Texas, with former Rep. Beto O’Rourke coming close to defeating Cruz in the blue wave year of 2018. But Trump expanded his margin last year in Texas compared to 2020, carrying Texas by 14 percentage points as Cruz defeated former Democratic Rep. Colin Allred by 9 points.
Allred told The Dallas Morning News last month that he is “seriously considering” another run for Senate against Cornyn. Cruz, meanwhile, told reporters Wednesday that he is staying neutral in this year’s Senate primary, saying both Paxton and Cornyn are friends.
“I have worked closely with both of them. I respect them both,” Cruz said. “And I trust the voters of Texas to make that decision.”
A divisive GOP primary could play into Democrats’ hands — especially if Paxton is the nominee. In the meantime, Democrats are watching the GOP primary process play out in Texas and other states. Democratic Senatorial Campaign Committee spokesperson Maeve Coyle noted that former New Hampshire GOP Gov. Chris Sununu announced Tuesday that he would not be running for that state’s open Senate seat.
“As Republicans face a nasty primary in Texas and an embarrassing recruitment failure in New Hampshire — coupled with a building midterm backlash across the map driven by their threats to Social Security, Medicare, Medicaid and their push to spike costs for families — Democrats will look for every opportunity to put them on defense,” Coyle said.
