Republican voters in Texas get their final say Tuesday in a drawn out, vitriolic and expensive primary campaign for a US Senate seat, a race that Democrats are watching closely in hopes that they could flip both houses of Congress in November.

President Donald Trump-backed U.S. Senate candidate Texas Attorney General Ken Paxton is running against incumbent Republican U.S. Sen. John Cornyn in the Texas GOP U.S. Senate primary runoff contest on Tuesday,

Ken Paxton was endorsed by President Trump in his campaign against John Cornyn, a four-term Republican senator. The winner will face James Talarico, a Democrat, in November.