Republican leaders rushed to throw their weight behind Ken Paxton following his big primary victory in Texas over the four-term US senator, John Cornyn, amid anxiety within the party over his prospects in November’s general election.

Hours after the race was called, Donald Trump – who backed Paxton, despite intense concern among establishment Republicans – took to Truth Social to attack his Democratic rival in the midterm elections.

James Talarico “may be the worst Texas candidate I have ever seen”, said the US president, claiming the Austin state representative and Democratic nominee for Texas senator was weak on crime and an advocate for open borders.

Reaching for a favored Republican attack line against Talarico, Trump claimed he was a vegan who “dislikes meat, not exactly a good way to be if you’re wanting to win an Election in Texas”.

The Democrat has denied being vegan. “I’ve been eating barbecue since before Ken Paxton’s first indictment,” he told a podcast earlier this week.

While Texas has not elected a Democrat to the Senate since 1988, Republican operatives have privately worried that Paxton’s long trail of legal troubles would make him a riskier standard-bearer than the incumbent.

Of the outgoing Cornyn, a veteran US senator who enjoyed the support of many of his Republican colleagues on Capitol Hill, Trump was more measured. “John will remain my friend for a long time to come,” he said.

Paxton’s victory sets up one of the most closely watched US Senate races of the 2026 cycle, as Democrats push to flip the seat for the first time in decades.

“A vote for Ken Paxton in November is a vote for a safer, stronger, and more prosperous America,” the Senate majority whip, John Barrasso, wrote on social media, calling Talarico “a far-left extremist” who was “too radical” for Texas. Bernie Moreno, a senator of Ohio, the likely incoming chair of the National Republican Senatorial Committee, called Talarico a “far-left freak” and added: “The voters have spoken, now Republicans must unite and win.”

Ted Cruz, who had not previously endorsed in the race, put out a statement. “Ken is a fearless conservative who spent years taking on Texas’s toughest battles as Attorney General,” he said. Tim Sheehy, a senator of Montana, called Talarico a “commie”, while the Texas governor, Greg Abbott, predicted Paxton would “destroy Talarico” and win the contest.

On the trail, Republican surrogates have zeroed in on a 2023 interview in which Talarico was asked what he loved beyond family and friends. “I love the trans children who showed up yesterday at the state capitol to advocate for their humanity,” he replied.

Brandon Gill, a representative, told a recent rally crowd: “What kind of grown man daydreams about trans kids?” Sarah Gonzales, a representative, told the same crowd to “check his hard drive”.

Talarico is running in part on a contrast of personal character against Paxton, who was impeached by the Republican-controlled Texas house in 2023 – on allegations that he abused his office to help a political donor who employed a woman with whom Paxton had acknowledged having an extramarital affair – before being acquitted by the state senate.

The US Department of Justice reportedly declined to prosecute Paxton in the final weeks of the Biden administration, despite federal prosecutors in Texas having believed there was sufficient evidence for an indictment. He also separately paid nearly $300,000 in restitution to resolve long-running securities fraud charges.

On social media, Talarico thanked Cornyn for his years of public service and sent a message to his supporters: “You have a place in our campaign.”

Democrats did not hide their preference for this outcome. The Texas Democratic party chair, Kendall Scudder, said Paxton “has spent decades in office abusing his power to serve special interests and enrich himself at Texans’ expense”.

The Senate minority leader, Chuck Schumer, and Kirsten Gillibrand, a senator of New York, who chairs the Democratic Senatorial Campaign Committee, put out a joint statement saying Paxton’s win put their party “one step closer to winning a Senate majority”.

“While Republicans are facing their nightmare scenario, tonight Democrats are one step closer to winning a Senate majority, and in November, Texas will send James Talarico to the Senate,” they wrote.

“Ken Paxton is so corrupt that even his own party tried to remove him from office, and during his tenure as Attorney General, criminals have walked free while Paxton and his wealthy donors have profited at the expense of Texas families.”