This Article explores the rise of “machines” in criminal adjudication. Human witnesses now often give way to gadgets and interpretive software, juries’ complex judgments about moral blameworthiness give way to mechanical proxies for criminality, and judges’ complex judgments give way to sentencing guidelines and actuarial instruments. Although mechanization holds much promise for enhancing objectivity and accuracy in criminal justice, that promise remains unrealized because of the uneven, unsystematic manner in which mechanized justice has been developed and deployed.