We call it justice--the assassination of Osama bin Laden, the incarceration of corrupt politicians or financiers like Rod Blagojevich and Bernard Madoff, and the climactic slaying of cinema-screen villains by superheroes. But could we not also call it revenge? We are told that revenge is uncivilized and immoral, an impulse that individuals and societies should actively repress and replace with the order and codes of courtroom justice. What, if anything,...