Texas Attorney General Republican Ken Paxton has his sights set on Washington.
On Tuesday, Paxton announced he's running for the U.S Senate. He's hoping to unseat Cornyn, who's represented Texas in the chamber since 2002.
"We have another great senator, Sen. Ted Cruz and it's time we have another great Senator that will actually stand up and fight for Republican values, fight for the values of the people of Texas, and also support Donald Trump in the areas he's focused on in a very significant way," Paxton said during his announcement on Fox News. "And that's what I plan on doing."
When will they face off?
Election day for the U.S. Senate seat is November 3, 2026.
While that seems a long way from now, the two will go up against each other earlier next year during the Republican primaries. Those will take place on March 3, 2026. Expect several campaign ads to be released between now and primary election day, along with a possible debate.
While it's still up in the air which Democrats will be in the race, it's likely whoever wins the Republican primary will also win the seat in November. Texas hasn't sent a Democratic U.S. Senator to Washington since the early '90s.
What are they fighting over?
So, with less than a year before Republican voters hit the polls, the pair is already facing off now on social media.
Paxton released an ad Wednesday morning painting Cornyn as a traitor to President Trump and the America First movement, and as soft on guns for helping to pass bipartisan gun legislation after the shooting in Uvalde.
"I can certainly point to many things like his gun restrictions, his lack of wanting to fund a border wall and disagreeing with Trump on that," said Paxton. "And even opposing President Trump's election in 2016 and his most recent election."
Cornyn also threw a jab himself, calling Ken Paxton a fraud on X and reminding voters that Paxton was impeached by members of his own party in 2023. Paxton, who was accused of abusing the power of his office to help a campaign donor, ultimately beat those charges.
During his two-decades in elected office, Paxton faced multiple allegations of bribery, self-dealing and other corrupt acts but he has never been convicted of a crime. Last year, Paxton cut a deal with state prosecutors to pay restitution and do community service in order to avoid standing trial on multiple felony fraud charges.
How long have they been in politics?
Cornyn, 73, has been in public office for more than 30 years. He served as an elected justice on the Texas Supreme Court from 1991 until 1997 and then as state attorney general from 1999 until 2002.
Since then, he's served in the U.S. Senate and is now on his fourth six-year term.
Ken Paxton, 64, entered politics in 2003 when he won the race to represent North Texas in the Texas House of Representatives. He served in that role until 2013, only leaving to move to the Texas Senate for one term.
He was elected Texas Attorney General in 2015 and has now held that position for a full decade.
What does this say about the Republican Party of Texas?
The announcement from Paxton points to the internecine war that's been brewing within the Republican Party in Texas.
The fight between Republicans has been brewing for years — something James Henson of UT Austin's Texas Politics Project calls the "conservative versus the very conservative."
Cornyn enjoys the support of the National Republican Senatorial Committee, a powerful body that helps get GOP members elected to the chamber, while Paxton is lauding support from far-right social media influencers.
What are Paxton's chances of winning?
While less than 24 hours have passed since Paxton's entrance, polls have already been conducted in the past that could preview how close the race will be.
A January statewide survey conducted by the University of Houston's Hobby School of Public Affairs showed that more Republican primary voters would definitely consider voting for Paxton than Cornyn, at 36% to 32% respectively. However, a higher percentage of that same demographic say they "would never" vote for Paxton than Cornyn, 19% and 15% respectively.
Mark Jones, political science fellow at Rice University's Baker Institute, believes it's still too early to predict who will win. But he shared with Houston Public Media how the race could play out, and a lot of it revolves around Trump.
"The optimal scenario for Paxton is that Trump retains his high level support among Republican primary voters, and then he endorses Paxton in the U.S. Senate Primary," said Jones. "In which case it would be virtually impossible for Cornyn to win."
A win for Cornyn, Jones said, would require basically the opposite.
"The most optimistic scenario for Cornyn is that due to his mismanagement of the economy Trump's popularity tanks, and at the same time he withholds an endorsement in the race and stays neutral," said Jones. "In which case Cornyn might have a fighting chance at defeating Paxton."
One thing is clear: This will likely be a very expensive battle. Nearly $200 million was raised between Sen. Ted Cruz and Colin Allred during their 2024 matchup. It's likely this race could see the same if not more financial support thrown behind the candidates.
Andrew Schneider contributed to this report.
The Texas Newsroom is a public radio journalism collaboration that includes NPR, KERA in North Texas, Houston Public Media, KUT in Austin, Texas Public Radio in San Antonio and other stations across the state.