Trump's Role in Texas GOP Senate Runoff Between Cornyn and Paxton

The only time Donald Trump and John Cornyn appeared on the same Texas general election ballot, Cornyn finished ahead by 72,417 votes.

That was in 2020, when Trump was seeking his second term in the White House and Cornyn was running for his fourth term in the U.S. Senate. Both men carried Texas. But Trump's 52% share of the statewide vote was the worst showing for a Republican presidential candidate in the Lone Star State since 1996, when Texas tycoon H. Ross Perot's independent bid siphoned votes from both major-party candidates.

As it turned out, 2020 was also an off-year for Cornyn. He won reelection with 53.5% of the vote — a comfortable margin but a sharp slide from his 61.5% share six years earlier. It was also less than the 55% he received in his first two Senate races.

All of this is background for what role Trump might play as Cornyn seeks to become the longest-serving U.S. senator in Texas history. Not long after Cornyn defied pre-election polls and edged Texas Attorney General Ken Paxton by just over 1 percentage point in the March 3 Republican primary, Trump signaled he would come off the sidelines and make an endorsement ahead of the May 26 runoff.

At the same time, the president said he expected the unendorsed candidate to fold his tent and concede. That was a bold ask, considering that about 60% of the GOP primary voters didn't want Cornyn to win and a different 60% didn't want Paxton leading the Texas ticket against Democrat James Talarico in the general election.

The near-universal assumption was that Trump would back Cornyn, given his status as the incumbent and his popularity among fellow Republicans in the U.S. Senate. But that didn't sit well with Paxton, one of Trump's top allies dating back to the president's first campaign in 2016. Paxton has said he has no plans to quit the race, though he hinted at conditions that appear unlikely to materialize.

Post-primary polling suggests Paxton is stronger with GOP voters, though his lead would shrink — but not disappear — if Trump endorses Cornyn. For now, Cornyn's best hope for survival in the runoff may be securing Trump's backing.

Meanwhile, Cornyn has launched a scorched-earth campaign against Paxton, highlighting his well-chronicled extramarital affairs and revisiting the legal and political controversies that dogged his tenure as attorney general, including his early indictment and his 2023 impeachment by the Texas House. Less often mentioned by the senator is that Paxton was acquitted by the Texas Senate and later resolved other legal challenges through a plea deal.

None of Cornyn's broadsides are likely to sway Paxton's most loyal supporters in the MAGA base, and the bitterness could linger even if Trump endorses Cornyn and helps him win the runoff.

That brings us back to the general election comparison at the start.

If Cornyn wins the nomination, he would likely lead a fractured Texas Republican Party into the general election. The same would likely be true if Paxton prevails. In either case, Trump would face pressure to help heal the divide.

The question is how helpful he would be in a midterm election that may favor Democrats — even in Texas.

Despite weaker showings in 2016 and 2020, Trump rebounded in 2024 with a solid 56% of the vote in Texas. But his standing in public opinion polls has slipped since then. A Texas Politics Project poll in February showed him underwater, with just 44% approving of his performance in the year since returning to the White House.

That poll was conducted before Trump decided to wage war on Iran, and before the price of gas went from around $2.70 a gallon last week to about $3.20 a gallon this week. Texas polling has yet to measure opinion on the conflict, but a national Quinnipiac poll last week found support for the war at just 40%.

If the Iran conflict grows less popular and gas prices approach $4 a gallon, Trump’s approval ratings may remain stuck in the mid-40s. That could make it harder for him to win back the swing voters who helped deliver his strong 2024 showing in Texas.

If Cornyn wins the nomination, he may once again need to prove that he’s more popular than Trump with general election voters to secure a fifth term.