US President Donald Trump has endorsed Texas Attorney General Ken Paxton in his bid to unseat incumbent Senator John Cornyn in next Tuesday's Republican primary run-off race.
By siding with Paxton, Trump is supporting a Texas politician who has long been a close ally of the president – but also one who comes with considerable political baggage.
Many Democrats have viewed Paxton as the weaker of the two candidates and relish what they believe is an opportunity to flip a Senate seat in a state that has a long history of electing Republicans.
Trump's move dismayed Cornyn's fellow Senate Republicans, many of whom have served with the Texan for decades and view him as a friend and ally.
Maine Senator Susan Collins called Paxton "ethically challenged". Alaska Senator Lisa Murkowski said she was "supremely disappointed".
Trump, however, appears to have different preferences.
The president is supporting a Texas politician who has long been a close ally of the president.
As attorney general, he backed Trump's efforts to overturn the results of the 2020 presidential election.
Paxton also travelled to New York City to rally for Trump during his 2024 trial – and conviction – over hush-money payments to adult film actress Stormy Daniels.
Like Trump, Paxton has a political history marked by scandal and legal challenges – and has established a reputation as a survivor.
He recently settled a federal corruption indictment without admitting misconduct.
In 2023, he was impeached by the Republican-controlled Texas legislature for alleged fraud and obstruction of justice – but acquitted in a state Senate trial.
Last year, his wife filed for divorce amid allegations that Paxton had had multiple affairs.
"I know Ken well, have seen him tested at the highest and most difficult levels, and he is a winner!" Trump wrote on his Truth Social website.
"John Cornyn is a good man, and I worked well with him, but he was not supportive of me when times were tough."
On Tuesday, Cornyn posted on X that he had voted with Trump more than 99% of the time.
He said: "It is now time for Texas Republican voters to decide if they want a strong nominee to help our GOP candidates down ballot and defeat Talarico in November, or a weak nominee who jeopardizes everything we care about."
This is not the first recent example of Trump backing a challenger against an incumbent Republican.
On Saturday Senator Bill Cassidy lost to a Trump-endorsed opponent in Louisiana's Republican primary.
On Tuesday evening, voters in Kentucky are projected to have chosen Ed Gallrein over incumbent congressman Thomas Massie in that state primary. Trump recruited Gallrein to run against Massie.
Those Republicans, however, had made clear breaks with the president.
Cassidy voted to convict Trump on impeachment charges in his 2021 Senate impeachment trial.
Massie irked the president for voting against key parts of his legislative agenda, including military operations in Venezuela and Iran.
By contrast, the 74-year-old Cornyn served in the Senate Republican leadership from 2012-24 and is viewed as a party loyalist – albeit one more allied to the Republican establishment.
But he didn't endorse Trump's re-election bid until January 2024 – well over a year after the president entered the race – a delay that Trump also noted in his endorsement post.
During the campaign, Paxton had highlighted Cornyn's votes for new gun regulation and accused him of being insufficiently aggressive in supporting immigration enforcement along the Texas-Mexico border.
Cornyn's side focused on Paxton's past political and legal scandals and perceived personal shortcomings.
Early voting is already under way in Texas for what polls had indicated was a close run-off race.
In their original matchup in early March, Cornyn had finished narrowly ahead of Paxton, but short of the 50% necessary to secure the nomination - despite outspending Paxton by more than $65m.
A day after those results, Trump promised to endorse a candidate and urge the other to drop out.
Months passed, however, before the president finally weighed in.
By siding with Paxton, he may have delivered a fatal blow to Cornyn's electoral chances.
The winner of Tuesday's primary will go on to face Democrat James Talarico, a Texas state legislator who secured his party's nomination over congresswoman Jasmine Crockett without a run-off.
It has been 32 years since a Democratic candidate won a statewide election in Texas, although Beto O'Rourke's 2018 Senate campaign came within 215,000 votes of ousting Senator Ted Cruz with more than eight million ballots cast.
Trump won the state in 2024 by 14%, but public opinion polls suggest a close contest heading into November's general election vote.
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