More details on the Panetti case are available in this story by Linda Greenhouse in the NYT.
Despite, or perhaps because of, his mental disorders, Panetti chose to represent himself at his trial, and so long as he met the standard of competence to make that decision, the trial judge had no choice under the Supreme Court's 1975 decision in Faretta v. California, 422 U.S. 806. Justice Blackmun had warned in dissent that the Court was creating a constitutional right to be a fool. In some cases, that means being a crazy fool. When a marginally competent defendant makes a Faretta motion, the trial judge is caught between Scylla and Charybdis. If the judge denies the motion and a reviewing court determines that the defendant was, in fact, competent to make the foolish choice, the resulting Faretta error is reversible per se. If the judge grants the motion, the trial can become a farce. Although reexamining Faretta is not the question presented in the present posture of this case, we can hope that the Court will understand that but for its ill-advised decision, Panetti would have had a lawyer who could have made a good case in mitigation from his mental illness and quite possibly avoided the death sentence in the first place. In an appropriate case, the Court should provide trial judges some slack between the level of competence at which the judge must allow the defendant to represent himself at the level at which he must not.
Some opponents of the death penalty like to speak in sweeping terms that we should never execute anyone with a "mental illness," as if that were a well defined and understood term. It is not. At its broadest, it means anyone diagnosable with any condition listed in the American Psychiatric Association's Diagnostic and Statistical Manual of Mental Disorders. That would be quite wrong, as the DSM-IV itself says. The criteria for including a condition in the DSM do not match the concerns of the law regarding moral responsibility. "In most situations, the clinical diagnosis of a DSM-IV mental disorder is not sufficient to establish the existence for legal purposes of a 'mental disorder,' 'mental disability,' 'mental disease,' or 'mental defect.'" The primary criterion for Antisocial Personality Disorder is "a pervasive pattern of disregard for and violation of the rights of others...." Not only should persons qualifying for this "diagnosis" not be exempt from punishment, they should be moved to the head of the line.
Clarification of the criteria for competence for execution would be a welcome development, but there is danger that the Court will paint with too broad a brush. Panetti believes that his sentence is the result of religious persecution rather than actual punishment for the murders he committed. Such claims can be heard in prisons all the time. I would be interested in hearing from people knowledgeable in the field if there is a ready way to distinguish between the kind of conspiracy theories that lots of people believe in and an actual delusion. Also, is there a good way to detect malingering of delusions can be detected? But even assuming Panetti's belief is a delusion, should that exempt him from a punishment otherwise warranted?