Trump Backs Ken Paxton Over Incumbent John Cornyn in Texas Senate Runoff

CNBC reported Tuesday that President Donald Trump delivered a last-minute Ken Paxton endorsement in the Texas Republican Senate primary runoff. The move blindsided four-term incumbent Sen. John Cornyn and landed just seven days before the May 26 vote.

Trump Throws Weight Behind a Hard-Line Ally

Trump made the announcement via Truth Social, calling Paxton a “true MAGA Warrior” who consistently delivered for Texas. He framed the incumbent as a fair-weather ally who fell short during politically difficult moments. Cornyn fired back on X, noting he voted with Trump more than 99% of the time. He urged Texas Republicans to consider which candidate gives the party the stronger path in November.

Also Read: What the 2026 Midterms Could Mean for Senate Control

Texas Attorney General Ken Paxton welcomed the backing enthusiastically, calling it Trump’s “complete and total endorsement” on social media. Early voting in the runoff opened Monday and closes Friday ahead of next Tuesday’s election.

A Pattern of Primary Interventions

This endorsement follows a clear and recent pattern. Trump’s support helped force out Sen. Bill Cassidy of Louisiana last weekend. Cassidy had voted to convict Trump during his second impeachment trial. Trump is also backing a primary challenger against Rep. Thomas Massie of Kentucky, who has repeatedly broken with House Republican leadership.

Also Read: Trump’s Endorsement Track Record in 2026 Primaries

Together these races are functioning as loyalty tests ahead of the 2026 midterms. Trump’s broader approval numbers have softened nationally, but he retains commanding strength among Republican primary voters. That gap gives his endorsements disproportionate force within the party.

What November Could Look Like

The runoff winner faces Democratic nominee James Talarico in the general election. A bruising primary fight raises questions about GOP unity heading into the fall campaign. Democrats are watching carefully, viewing a weakened or controversial Republican nominee as a potential opening in a state that has trended more competitive in recent cycles.

Cornyn warned voters directly that a weaker nominee could jeopardize down-ballot Republican candidates across Texas. Whether that argument cuts through against a Trump stamp of approval remains to be seen after May 26.

Read Next: US Political Uncertainty and Market Volatility in 2026