AUSTIN (VINnews) – Texas Attorney General Ken Paxton defeated incumbent Sen. John Cornyn in the Republican primary runoff for U.S. Senate on Tuesday, a stunning upset powered by a late endorsement from President  Trump.

Paxton, a staunch Trump ally, overcame Cornyn’s early lead from the March 3 primary — where Cornyn edged him 42%-40.5% — to secure the GOP nomination. The victory highlights the significant sway of Trump’s backing in the state’s conservative electorate.

Fox News anchor Bill Hemmer underscored the endorsement’s impact during election coverage.

“Endorsements on behalf of Donald Trump matter,” Hemmer said. “30 point swing. The flip in these counties is extraordinary from 2.5 months! The only difference? Trump endorsed Paxton.”

Paxton received Trump’s endorsement just one week before the May 26 runoff, a move that dramatically shifted momentum in the high-stakes race. Trump praised Paxton as a “fighter” while criticizing Cornyn’s loyalty on key issues.

The contest, one of the most expensive Republican primaries in recent history, exposed deep divisions within the Texas GOP between establishment figures and the MAGA wing. Cornyn, a four-term senator, emphasized his legislative record and experience, but struggled against Paxton’s grassroots appeal and Trump alignment.

With the primary now decided, Paxton advances to the November general election against Democratic nominee state Rep. James Talarico. Texas remains a reliably Republican state in Senate races, making Paxton the strong favorite to succeed Cornyn.

Results continued to come in late Tuesday as polls closed across the state.