Trump backs Paxton as Texas GOP Senate runoff enters final week

President Donald Trump endorsed Texas Attorney General Ken Paxton May 19 in the Republican primary runoff for U.S. Senate, giving a major boost to Paxton’s effort to unseat incumbent Republican Sen. John Cornyn just days before voting concludes.

Trump announced the endorsement in a Truth Social post, calling Paxton “a true MAGA Warrior who has ALWAYS delivered for Texas” and praising his loyalty on issues including border security and battles over Senate rule changes to pass key legislation. 

He contrasted Paxton with Cornyn, describing the latter as “a good man” but one who was “very late” in endorsing Trump for the presidency and failed to be “supportive of me when times were tough.”

The endorsement came more than two months after Trump first said he would weigh in on the race and just days before the May 26 runoff. Tens of thousands of Texans had already cast ballots during early voting by the time Trump weighed in, according to the Texas Tribune. 

Trump praised Paxton’s support for ending the Senate filibuster and for backing the SAVE America Act, a Republican election-integrity proposal that has become a priority for Trump allies in Congress.

The runoff is one of the most costly Senate primary fights in U.S. history. Campaigns and outside groups have poured well over $100 million into television ads, mailers, and digital campaigns. Early voting is underway through May 22, with Election Day set for May 26. The winner will face Democrat James Talarico in the November general election.

Paxton and Cornyn advanced from the March 3 primary after neither won a majority of the vote. Cornyn led with about 42%, followed closely by Paxton at roughly 40%. 

Paxton has positioned himself as a hard-charging conservative fighter aligned with Trump’s agenda. Cornyn, a four-term senator, has emphasized his experience in Washington, strong overall alignment with Trump’s positions in recent years, and concerns that Paxton’s legal issues — including a 2023 impeachment trial and ethics investigations — could make him a weaker general-election candidate and hurt Republicans in the fall.

Trump’s endorsement also underscored lingering divisions in the aftermath of the 2020 election. Cornyn did not object to certifying Biden’s 2020 victory on January 6, 2021, arguing there was a lack of evidence of widespread fraud. He stated he would not challenge the result “based on unproven allegations.” Paxton, by contrast, led a major multi-state lawsuit supporting Trump’s challenges.

Prediction markets reacted sharply to Trump’s endorsement. Traders on Polymarket quickly moved to give Paxton roughly a 94% chance of winning the nomination, up significantly compared with his odds before the announcement.

Cornyn responded by highlighting his support for Trump’s agenda and arguing that Texas voters should nominate a candidate strong enough to win in November and help other Republicans on the ballot. 

Paxton called Trump’s endorsement one of the most significant of his career and urged supporters to vote early.