Texas Attorney General Ken Paxton's entering the U.S. Senate race against incumbent John Cornyn could serve as a litmus test for a Republican party in flux.

Texas Attorney General Ken Paxton announced his bid to challenge current Sen. John Cornyn in the state's 2026 Republican primary election.

Texas Attorney General Ken Paxton’s decision to challenge Sen. John Cornyn sets up what’s likely to be a bitter and expensive Republican primary – and a battle for President Donald Trump’s endorsement.