President Donald Trump escalated his intervention in the Texas Republican Senate primary runoff on Sunday, posting a full-throated endorsement of Attorney General Ken Paxton and directly attacking incumbent Senator John Cornyn as disloyal. In a series of posts on his social media platform, Trump declared Paxton “WILL NEVER LET YOU DOWN!!!,” framing the race as a test of allegiance to his presidency and agenda.
“TEXAS, REMEMBER! Ken Paxton was a GREAT Attorney General, probably the best in the Country. He was also very loyal to your favorite President, ME, as the Dumocrats played their ultimate game of Weaponization, and failed, BADLY!” Trump wrote. He touted his own electoral track record in Texas, claiming he won the state “all three times” with record vote totals.
The former president specifically targeted Cornyn, accusing him of insufficient support for the “SAVE AMERICA ACT” — a legislative package focused on voter ID requirements, proof of citizenship, and restrictions on mail-in ballots. “Ken's opponent was VERY disloyal to me, as President, and didn't fight hard enough,” Trump said, urging voters to choose Paxton in Tuesday's runoff.
This latest broadside follows Trump’s formal endorsement of Paxton last week, a move that blindsided many Senate Republicans and deepened intraparty tensions. Trump described Paxton as “a true MAGA Warrior who has ALWAYS delivered for Texas,” while snubbing Cornyn, a three-term senator and former Senate GOP whip.
The runoff has become a proxy war between the party's establishment and its Trump-aligned wing. Cornyn, who has largely avoided direct confrontation with Trump, now faces an aggressive challenge from Paxton, who has leaned heavily on Trump’s backing and his own record as a conservative legal firebrand. Recent prediction markets, as reported by Kalshi, suggest Paxton holds a strong lead heading into Election Day.
Republican senators have not hidden their frustration with Trump’s decision. Senator Susan Collins of Maine called Paxton “an ethically challenged individual,” adding, “John Cornyn is an outstanding senator and deserved in my judgment the president's support. Obviously it's the president's call but I'm disappointed that he did it.” Collins’ comments reflect broader unease within the Senate GOP conference, where Cornyn is seen as a reliable institutionalist.
Paxton himself faces ongoing legal scrutiny, including a long-running securities fraud case and an FBI investigation into corruption allegations — issues that have not deterred Trump from embracing him. The attorney general has consistently denied wrongdoing and cast the investigations as politically motivated.
For his part, Cornyn has declined to endorse Paxton ahead of the runoff, as previously reported, signaling the depth of the rift between the two candidates. The Hill has reached out to Cornyn’s campaign for comment but has not yet received a response.
Tuesday’s outcome will have significant implications for the Senate’s balance of power and for Trump’s continued influence over the Republican Party. A Paxton victory would mark another triumph for Trump-backed insurgents, while a Cornyn win could signal limits to that pull — even in deep-red Texas.
