Texas voters will pick a Republican nominee for U.S. Senate in a primary runoff election on Tuesday. U.S. Sen. John Cornyn was the top vote-getter in the March 3 primary, but strong showings by two GOP challengers forced the four-term incumbent to a head-to-head matchup with state Attorney General Ken Paxton. Paxton placed second in the primary and received President Donald Trump’s endorsement. Also on the ballot are primary runoffs in more than a dozen congressional districts, plus state contests for lieutenant governor, attorney general and others.