Psychiatric Testimony and the Insanity Defense

The academic and liberal practitioners who drafted the Model Penal Code declared, "evidence that the defendant suffered from a mental disease or defect is admissible when-ever it is relevant to prove that the defendant did not have a state of mind that is an element of the crime."¹⁰ A number of courts concluded this was a constitutional requirement. But the elected legislators and the citizenry were outraged when the media focused public attention on these practices.

The infamous "Twinkie" defense (in which Diamond did not testify) and subsequent verdict set off a night-long riot in San Francisco.¹¹ The defendant, who had killed the mayor and the first openly gay city supervisor, offered psychiatric testimony not that he was insane but that he lacked the "premeditation" requirement necessary for murder under the California statute. A jury of his peers believed his psychiatrists and reduced his crime to voluntary manslaughter.

Although misinterpreted in the media as the "Twinkies made him do it," the psychiatric testimony that convinced the jury was that the defendant was depressed and that his uncharacteristic binge of junk food eating and recent weight gain were symptoms of his depression. The defendant committed suicide after serving his lesser sentence, which suggests that the psychiatric diagnosis might have been correct. Whether the diagnosis was clinically correct or not, under any conventional commonsense account of the killings, the defendant had planned, premeditated, and intended the crimes. The people of California and their legislators felt betrayed by the verdict and wanted to eliminate diminished capacity defenses.

This is what Justice Souter was suggesting Arizona should be able to do during the oral arguments in Clark. However, given the basic conception of criminal law that there is a mental element to the crime often specified in the language of the statute and that the prosecution has to prove this mental element (intent, premeditation, etc) beyond a reasonable doubt, diminished capacity is not that easy to eradicate. After the Twinkie verdict, California voters took this matter up and attempted to eliminate diminished capacity by adopting Proposition 8. The proposition excluded testimony on capacity, but lawyers went on trying to proffer expert psychiatric evidence to prove that their clients lacked the "actual" mental state required by the statute.

Eventually, California's legislature tried to narrow Dr Diamond's loophole by rewriting the criminal statutes to eliminate the grounds for these psychiatric defenses. From this perspective, when Arizona legislators made the killing of a police officer a capital offense, they unwittingly included language that could be understood as requiring defendants such as Clark to know or believe he was killing a police officer and not an alien. To prohibit such diminished capacity defenses, the Arizona legislature simply passed a law that excludes expert psychiatric testimony as evidence on the mental element of the crime, and the Arizona courts upheld that law, as did Justice Souter.

It is my contention that after the attempted assassination of President Reagan and John Hinckley's successful insanity defense, the US Congress attempted to do just what California and Arizona tried to do—eradicate diminished capacity. I testified at congressional hearings at the time and followed the legislative process.¹² Federal legislators made it clear that these matters had for too many years been left in the hands of judges and academics; it was time for them to speak as the voice of the people. The Insanity Defense Reform Act of 1984 that was subsequently passed narrowed the Federal Insanity Defense and states that other than in presenting the insanity defense, "mental disease or defect does not... constitute a defense."¹³ But it has not been easy to put Dr Diamond's genie back in the bottle. Lower federal courts and the Justice Department have interpreted the 1984 act as not prohibiting expert testimony in diminished capacity defenses. And constitutional scholars have continued to argue that excluding relevant and probative expert psychiatric testimony that might be the only relevant evidence that can show the defendant lacked the necessary intent does violate the Constitution.¹³

It was these constitutional arguments that were made by the APA and other amici and that Justice Souter rejected. To do so, he accepted the Arizona legislature's judgment that psychiatric expertise is often misleading and confusing to jurors and not based on a solid scientific foundation. Therefore, under Arizona's laws of evidence it can be excluded from the courtroom. If Justice Souter's opinion ratified those biases, I do not think he shares them. He was, I believe, attempting the difficult constitutional task of stuffing Dr Diamond's genie of diminished capacity back into the bottle. First, he interpreted Arizona's Law of Evidence not as barring all psychiatric expertise, but rather as channeling it all into the defendant's insanity defense. Second, he indicated that testimony about intent was allowed, including testimony from a psychiatrist, but only if the psychiatrist, like any other witness, was reporting a conversation or an observation made at the time of the crime. What the psychiatrist cannot do is provide his or her professional opinion about the defendant's state of mind or diagnosis for the Court's consideration on intent.

For those who are concerned about the future implications of the Clark decision, it is worth reemphasizing that it made very little new law. Furthermore, Justice Kennedy, who is increasingly the bellwether of the Court in divisive cases, took a position much like that of the APA. And in the long run, it often happens that US law finds more wisdom and better precedents in the minority opinions of our Supreme Court than in the opinions of the majority.