In the past twelve months the national news has introduced us all to some remarkably loathsome people wielding considerable power from very high places. How does this come about? A complete list of these creatures would be long and unwieldy, but a short list, on the lines of the FBI’s Most Wanted, and treated as character studies, allows us to reach some conclusions, the most important one being that we are dealing here with is entrenched mediocrity—intellectual, moral, and spiritual. John Brennan, former head of the CIA under Obama, is an Irishman, born in New Jersey, 1955, whose...