If senators got report cards the way children do in school, Ted Cruz’s would say “does not play well with others†every time. He’s been called the Senate’s “most reviled member,†and that’s just among his fellow Republicans. But the junior senator from Texas seems to like it that way. His failures inside the Beltway are successes outside, where he points to them to show he is the only one standing up to what he likes to call the “Washington cartel.†The more Washington hates him the more those who hate Washington love him. That’s his operating assumption, and it’s...