The Republican Primary Senate fight between incumbent John Cornyn and Attorney General Ken Paxton is the most consequential GOP race since 2010, when then Sen.

John Cornyn and his newly announced challenger, Attorney General Ken Paxton, are trashing each other's records. Analysts have said the candidates must raise a lot of money to get their message out in this large state.

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.