It’s a well known story: When Ted Cruz went to work for the George W. Bush presidential campaign in 2000, he had a lot going for him. He was in his 20s, a Texan, and smart, boasting a Harvard Law degree and a Supreme Court clerkship. It didn’t hurt to be young Hispanic man in a campaign looking for Latino votes. But Cruz was so self-aggrandizing and irksome that he managed to annoy folks at the headquarters in Austin so much that he never won a coveted slot at the White House. When Bush took office, Cruz was relegated to...