Choosing between insanity and guilt

How did the insanity defense originate?

The seeds were planted by the Romans, who took into account a defendant’s mens rea—i.e., state of mind—when a crime was committed. By the fourth century, St. Augustine was referring to “suddenly unbalanced” people who “were not found guilty because of the fact that they had done these things unknowingly and not freely.” In the 13th century, England’s highest jurist, Henri de Bracton, said that some people did not grasp their actions because they were “not far removed from the brute.” This notion became law with the 1724 murder trial of Edward Arnold, who shot one Lord Onslow because he thought Onslow was “in his belly and Bosom.” The judge ruled that to be acquitted, the accused must “not know what he is doing, no more than an infant, than a brute, or a wild beast.” The “wild beast rule” held sway in England for more than a century.

Who set the modern legal standard?

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In 1843, a Scottish woodcutter named Daniel M’Naghten shot and killed the secretary of British Prime Minister Sir Robert Peel. Witnesses testified to M’Naghten’s bizarre behavior, which included plunging himself in the river “to obtain relief from the burning pain” in his head. He was found not guilty by reason of insanity. Public uproar was so great that Parliament soon passed a strict burden of proof: Acquittal was allowed only if the defendant was so deranged “as not to know the nature and quality of the act he was doing, or if he did know it, that he did not know that what he was doing was wrong.” The M’Naghten Rule, popularly known as the “right-wrong test,” seemed so clear and simple that it was rapidly adopted throughout the United States.

Why is the defense so controversial?

Because today it takes the black-and-white question of guilt or innocence into the ambiguous province of psychiatry. To determine whether a defendant is insane, juries must make nuanced calls about their internal mental states and motives. Prosecutors and defense lawyers inevitably summon psychiatrists as “expert witnesses” to help them with that task, even though psychiatry does not recognize the term “insane” and is uncomfortable with questions of right and wrong. In nearly every case, the prosecution can produce a psychiatrist to testify that the defendant understood his or her actions. Just as surely, the defense can produce a psychiatrist to assure the jury that the defendant did not. The result, many psychiatrists and legal experts say, is a farce that damages both psychiatry and the law.

What are the objections to the insanity defense?

The primary grievance against it is that it produces wildly inconsistent verdicts. In 1981, John Hinckley tried to kill President Reagan in the deluded belief that he could win the heart of actress Jodie Foster. He was found legally insane and was confined to a Washington, D.C., mental hospital, where he remains today. But the year before, John Wayne Gacy pleaded insanity in the murders of 33 young men, most of whom he buried beneath the crawl space of his Illinois home. Deliberating for just two hours, the jury rejected his defense, and Gacy was executed. In 1991, Jeffrey Dahmer admitted killing 17 young men, storing some of their body parts in his refrigerator, and eating them. Dahmer was declared legally sane and sentenced to 15 consecutive life terms, primarily because he told police, “It’s hard for me to believe that a human being could have done what I’ve done, but I know that I did.”

How often is the defense invoked?

Very infrequently—in just one-quarter of 1 percent of felonies. And it fails in two-thirds of those cases. Insanity cases garner headlines simply because they’re often associated with sensational murder trials. Defense lawyers are actually wary of hauling out the plea, fearing that juries will see it as an act of desperation or deceit. Also, there is an inherent dilemma. By depicting his client as so disturbed he could not understand that it was wrong to kill, a lawyer makes it more likely that a judge or jury will lock him away forever.

Do state laws vary?

Each of the 50 states, and the District of Columbia, has its own insanity statutes. About half use a test set by the American Law Institute in the 1950s. This absolves a defendant from criminal responsibility if “he lacks substantial capacity” to appreciate the wrongfulness of his conduct or to follow the law. Roughly a third of the states use the stricter M’Naghten Rule. Another six use a version of M’Naghten that allows the defense of “irresistible impulse.” This essentially means the accused could not control his actions. Three states—Montana, Idaho, and Utah—have abolished the insanity defense altogether.

Is there an alternative?

Yes. Today, 14 states have embraced the verdict of “guilty but mentally ill,” and the concept is gaining ground elsewhere. Under this finding, the insane are not absolved of all responsibility for their crimes, and must do some jail time in addition to receiving psychiatric treatment.

The sins of the mother

At least 29 nations, including Canada, Italy, and the United Kingdom, have specific laws that put murders committed by emotionally disturbed mothers in a special category. “These countries realize that there is something unique and different about these crimes,” says Michelle Oberman, a law professor at Chicago’s DePaul University who has studied infanticide. But in the U.S. there are no such laws, and prosecutors must exercise their own judgment in how to handle murders committed by mothers. In most cases, prosecutors have sought the maximum penalty—including death in the states that have that option. But Oberman and other experts say juries often shy away from the death penalty in these cases, reasoning that any mother who kills her children must be insane. The most famous example was Susan Smith’s 1994 murder of her two sons, ages 14 months and 3 years; she strapped them into her Mazda and let it roll into a South Carolina lake. Prosecutors sought the death penalty, but Smith was sentenced to life imprisonment, after her lawyer showed that she’d been psychologically abused by her mother and stepfather. Men who murder their own offspring rarely get similar sympathy, legal experts say. “It’s harder to make allowance for a father who kills,” said Lita Linzer Schwartz, co-author of a book on women who kill their children. “It’s not due to hormonal changes, that’s for sure.”