After attacking the Texas attorney general, who won the G.O.P. nomination, Senate Republicans are pivoting sharply to support him in what is now a competitive race.
The breadth of Mr. Cornyn’s loss showed the enduring unpopularity of Republican elected officials in Washington among the most ardent Republican voters.
Senators are angry President Trump turned on a respected former leader whom they consider a loyal Republican. Now Mr. Trump faces resistance from his own embittered ranks.