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 on Tuesday night announced a primary challenge against longtime Sen. John Cornyn, setting the stage for a battle between two politicians representing different parts of the Republican Party.

Texas Attorney General Ken Paxton launched his long-anticipated campaign Tuesday for the 2026 Senate race to challenge Sen. John Cornyn, settling up what is expected to be a bitter and expensive primary that some fear could hurt Republicans in the general election.