For nearly two centuries in the United States, the punishment of crime was largely aimed, in theory and in practice, at prevention, rehabilitation or incapacitation, and deterrence. In the mid-1970s, a sharp-and some argued permanent-shift occurred. Punishment in the criminal justice system became first and foremost about retribution. Retribution trumped rehabilitation; proportionality outweighed prevention. The retributivist sea change was short-lived,...