U.S. Sen. John Cornyn is declining to endorse fellow Texas Republican Ted Cruz for re-election to the Senate in 2018, just as Cruz did not back Cornyn for another term two years ago... Cruz is facing the prospect of a serious challenger after he upset some Republicans by expressing no support for presidential nominee Donald Trump in July at the party's national convention. U.S. Rep. Michael McCaul of Austin, who has been urged to take on Cruz, has not ruled out a run...