A group supporting Texas Attorney General Ken Paxton's bid for fellow Republican John Cornyn's Senate seat is planning to air an advert in Palm Beach, Florida, over the weekend attacking the incumbent congressman, according to Axios.Newsweek contacted Cornyn and Paxton for comment, via email and online inquiry form respectively, on Friday outside regular office hours.Why It MattersIn April, Paxton announced he was mounting a primary challenge against Cornyn, who has held the seat since 2002, setting up a high-stakes contest between two Texas Republican big hitters ahead of the 2026 midterm elections.Paxton has portrayed himself as the candidate aligned with Trump's Make America Great Again movement, vowing to "champion President Trump's legislative priorities."The contest offers a snapshot of grassroots Republican opinion in Texas, and a Paxton win could give the Democrats a shot at their first Texas Senate seat in 33 years, according to one poll.What To KnowOn Thursday, Axios reported that Preserving Texas, a pro-Paxton campaign group, was planning to air an attack ad over the weekend via Fox News, Newsmax and the Golf Channel.The advert is targeting Palm Beach, Florida, where Trump's Mar-a-Lago resort is located. The publication said the videos were being aimed at "an audience of one: President Trump."The attack ad allegedly criticizes Cornyn for backing a 2022 bipartisan gun safety bill that he helped negotiate, causing Trump to label the Senator a "RINO," which means Republican in name only. "As usual, President Trump was right," the ad says, per Axios.Citing "a person familiar with the buy," the publication said Preserving Texas was spending about $60,000 to air the video across the three networks.In 2022, as a response to Cornyn's support for a bipartisan gun safety bill, Trump wrote on Truth Social: "The deal on 'Gun Control' currently being structured and pushed in the Senate by the Radical Left Democrats, with the help of Mitch McConnell, RINO Senator John Cornyn of Texas, and others, will go down in history as the first step in the movement to TAKE YOUR GUNS AWAY."More recently, Cornyn has praised Trump over his efforts to achieve a ceasefire between Russia and Ukraine.The Texas Senate primary fight has already turned heated, with Cornyn calling Paxton "a con man and a fraud," while the attorney general previously said Cornyn was part of "the Bush wing of the GOP."In 2023, Paxton was acquitted by the Texas Senate of 16 articles of impeachment, including corruption, misusing official information and abusing his official capacity.What People Are SayingA spokesperson for Senator John Cornyn told Axios: "Corrupt Ken Paxton ordered up another mediocre campaign video that predictably lies about Senator Cornyn's long career of strongly supporting Second Amendment Rights. As an avid hunter himself, Senator Cornyn supports the constitutional right to carry and always has."While announcing his primary challenge in April, Texas Attorney General Ken Paxton told Laura Ingraham: "We have another great U.S. senator, 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 that he's focused on in a very significant way. And that's what I plan on doing."What Happens NextThe president has not endorsed Cornyn or Paxton in the primary battle. The general election for the Texas Senate seat is scheduled for November 3, 2026.