He knew that the world thought what he'd done was terrible. That's what makes him sane. The jury eventually disagreed with Dietz, finding that Hinckley had to have been crazy to shoot the U.S. president. But the case brought Dietz a notoriety that has never faded. To this day, he remains the lead consultant to the FBI on serial killers.
Mankind is essentially instinctual and riddled with bad impulses.
Dietz says his pessimistic outlook has been shaped by seeing the worst of the worst. And he is most adept at explaining what makes the criminal mind tick. His preparation for trial is legendary. Where other psychiatrists often testify in terms that confuse, Dietz instructs jurors with the simple details of a case. He insists on seeing every piece of evidence.