The Supreme Court's 2006 decision in Clark v Arizona¹ was one of the most unexpected defeats the American Psychiatric Association (APA) has had since it began regularly submitting amicus briefs to the Court 35 years ago. Justice Souter, who wrote for the majority, ruled that Arizona's vanishingly narrow insanity defense was not unconstitutional and, more troubling to forensic psychiatrists, he decided that on the issues of intent or premeditation (the mental elements of the crime), Arizona could prohibit expert psychiatric testimony on the grounds that it was unreliable and confusing to jurors.

Leading forensic practitioners read the opinion as hostile to the insanity defense, dismissive of psychiatric expertise in the courtroom, and "skeptical about the evidence of mental disorders."^2,3 And let it be said that legal scholars agreed with the forensic psychiatrists and thought that Justice Souter's decision was wrongly decided and poorly reasoned.⁴ Paul Appelbaum, now chair of the committee that prepared the APA briefs and an expert on law and psychiatry, worried that the legacy of the Clark opinion might be "to exert unfortunate influences involving mental health issues far removed from criminal law."

Justice Souter's decision was certainly a kick in the stomach to the drafters of this amicus brief, which was submitted to the Court on behalf of the APA, together with the American Academy of Psychiatry and Law and the American Psychological Association. A great deal of careful thought and collaborative effort had gone into an impressive brief in which forensic psychiatrists and psychologists had been able to work out a professional consensus with their lawyers on the difficult legal, constitutional, and scientific issues.

Justice Souter rejected all of the carefully crafted arguments; therefore, a certain amount of disappointment and disgruntlement was to be expected. However, I think it would be a mistake to conclude that Justice Souter is somehow biased against psychiatry, or that this disappointing decision constituted a major setback for psychiatry.

This was the first time in the history of the Supreme Court that the Justices have dealt directly with both the insanity defense and the admissibility of psychiatric testimony on criminal intent. Both issues are complicated, but they are basic to the understanding of the role of modern psychiatry in determining criminal responsibility and deserve the attention of every psychiatrist. In what follows, I shall try to present the Clark case in a historical context, explain in somewhat oversimplified terms the complex legal issues surrounding it, and suggest what I believe Justice Souter was attempting to accomplish by his decision.

Biased ruling?

There have been numerous other cases in the Supreme Court during the years of Justice Souter's tenure that to a significant extent turned on our psychiatric diagnoses and scientific expertise. In almost all these cases, Souter joined the Justices who took positions closest to those supported by the APA. For example, he joined Justice Stephens' majority in striking down capital punishment for persons with mental retardation in Atkins v Virginia.⁵ In reaching this result, Justice Stephens cited the APA's assurances about the reliability and validity of the DSM diagnosis of mental retardation and the objectivity of qualified mental health profession- als who make the diagnosis. Justice Souter also joined a controversial majority opinion by Justice Kennedy that cited a variety of psychiatric and psychological scientific evidence about adolescent development to prohibit capital punishment for 16- and 17-year-old offenders.⁶ And most important to psychiatric clinicians, he joined the majority in the landmark Jaffee v Redmond case that supported psychotherapist-patient privilege.⁷ This record does not suggest Justice Souter is biased against psychiatry.

If Justice Souter is not biased, then what accounts for the Clark decision? There can be no definitive answer, but it does appear that Souter's opinion started out tracking the brief submitted to the Supreme Court by the Solicitor General of the United States, who intervened in the case and strongly supported the state of Arizona.⁸ The Solicitor General is appointed by the President. His support of the state of Arizona probably had more to do with the conservative constitutional emphasis of the new "federalism" (the old states' rights) than it had to do with hostility toward psychiatry.

Seen from this "federalist" perspective, Justice Souter's decision in the Clark case protects the traditional lawmaking authority of the legislature of Arizona. And that conservative legal tradition gives the states wide leeway in formulating their criminal law and test of insanity. Take a step back from our professional psychiatric point of view and look at Justice Souter's decision through a wide lens; what one sees is that the Supreme Court cautiously and conservatively left the law pretty much where they found it. The Constitution sets no specific standard for the insanity defense. Arizona is not required to change its laws and neither is any other state. But, on the issue of psychiatric testimony, Justice Souter did unfortunately reject the Solicitor General's approach, which reached the same result without criticizing the expertise of psychiatry.

Background
Before discussing those more complicated legal issues about criminal intent in Clark v Arizona, the psychiatric aspects of the case need to be explained. Clinicians will recognize Eric Clark's story as another American tragedy that testifies to the inadequacies of the current mental health system and the lack of proactive psychiatric services. Clark was 17 years old and had adolescent-onset schizophrenia. His symptoms were typical of classic Capgras syndrome; he was delusionally convinced that the people around him, including his parents, were being replaced by aliens who were dangerous to him. He believed that aliens had taken over the police force in his hometown of Flagstaff. His parents realized that something was wrong, but they were unable to obtain treatment for him even in the presence of this flagrant psychotic ideation. Only when he became violent and shot a Flagstaff policeman (apparently believing that he was killing an alien) did he obtain the inpatient care he needed. After 2 years of treatment for "paranoid schizophrenia," he was declared competent to stand trial and the state of Arizona then prosecuted him for the capital offense of killing a police officer.