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Law professors explain why insanity defense is difficult to prove

Law professors explain why insanity defense is difficult to prove

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SALT LAKE CITY -- The trial of Brian David Mitchell is scheduled to resume in federal court Monday. The focus is expected to shift to a battle of expert witnesses who will argue for and against the proposition that Mitchell cannot be found guilty because he was insane at the time of the alleged crime.

Cases using the insanity defense usually draw a great deal of news coverage. The increased coverage may give the impression that the defense is widely used, when in actuality it is seldom used and rarely successful.

Lawyers for John Hinckley, Jr. mounted one of the most famous insanity defenses. In 1981 he attempted to assassinate then-President Ronald Reagan to impress actress Jodi Foster. One year later, a jury found him not guilty by reason of insanity.

Public outcry over the verdict led to the Insanity Defense Reform Act of 1984 which made it significantly more difficult to obtain the not guilty verdict and shifted the burden to prove insanity onto the defense.

"Congress has said that has to be proved by a 'clear and convincing' standard," said Paul Cassell, a law professor at the University of Utah.

The Mitchell case has also drawn a lot of media attention. Like the Hinckley case, the defense does not contest the basic facts. But the jury faces the potentially-difficult task of determining whether Mitchell was insane when he kidnapped Elizabeth Smart.

"Whether he knew it was wrong, and that's essentially the $64,000 question here," said Daniel Medwed, also a professor at the University of Utah law school. "It will probably come down to a battle of expert witnesses."

The term "insanity" is a legal concept, not a psychiatric concept of mental illness. Whether a person has a diagnosed mental disorder is not sufficient reason, to relieve them from all responsibility for criminal acts.

"It's really hard to get inside the defendant at the time of the crime and figure out what they knew," said Teneille Brown, associate professor of law at the University of Utah.

Because it is so hard to prove insanity, that defense is only used in about one percent of criminal cases and successful in just a fraction of those.

"If the jury's on the fence about whether Mitchell was insane or not, they have to convict in this case," Cassell said.

After the Hinckley verdict, Idaho, Montana and Utah abolished the insanity defense. The Mitchell case is being tried in federal court, so Utah law does not apply.


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Candice Madsen


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