Texas GOP voters oust Cornyn in Paxton upset

Republican primary voters on Tuesday rejected U.S. Sen. John Cornyn, one of the Senate's most senior GOP members, in favor of Trump-backed Texas Attorney General Ken Paxton.

Why it matters: Cornyn's loss marks one of the most significant defeats for a Republican senator in years and underscores how loyalty to President Trump continues to reshape GOP primaries nationwide.

• Trump gave Paxton a last-minute endorsement in the runoff.

What they're saying: "Tonight is the beginning of the fight to preserve every value we hold dear," Paxton told supporters, referring to his upcoming general election campaign against Democrat James Talarico.

• "Tonight we've come up short in this primary runoff," Cornyn told supporters in Austin. "I trust the voters of Texas, and they made their decision. I must respect it."

By the numbers: With 53% of the votes counted at 8:25pm, Paxton had 62.7% of the vote compared to Cornyn's 37.2%.

• The AP called the election in favor of Paxton an hour after polls closed Tuesday.

Zoom in: Paxton successfully cast the race as a referendum on the party establishment, energizing grassroots conservatives while dodging concerns about the legal scandals and impeachment fight that dogged much of his tenure as attorney general.

• The race became one of the country's most closely watched Senate primaries, fueling millions in fundraising and outside spending.

What we're watching: Cornyn and his supporters warned that the outcome could complicate Republicans' efforts to hold the seat in November against Talarico, a state representative from Austin.

• Paxton's win gives Democrats a potentially more polarizing Republican opponent than Cornyn.

Reality check: A Democrat hasn't won a statewide office in Texas in more than three decades.