How Successful Is The Insanity Defense? A Statistical Analysis

The insanity defense is a legal strategy that allows defendants to avoid criminal liability by proving that they were not in a sound state of mind when they committed the crime.

The defense has been controversially applied over the years, with some arguing that it is too frequently used to exonerate criminals.

In this article, we will examine the success rate of the insanity defense in the United States.

Success Rate

According to various criminal studies, only about one percent of all felony cases in the United States involve the use of the insanity defense.

Moreover, even when the defense is asserted, it is successful in only about 30 cases every year.

This means that the insanity defense is rarely used and even more rarely successful.

Burden of Proof

Originally, most states required that, when a defendant asserted a defense of insanity, the prosecutor was required to prove beyond a reasonable doubt that the defendant was not insane.

However, in 1982, John W. Hinckley was acquitted of the attempted assassination of President Ronald Reagan on the basis of an insanity defense, and this result caused many states to reform their insanity laws.

Many states shifted the burden of proof from the prosecutor to the defense, requiring defense attorneys to show by clear and convincing evidence or by a preponderance of the evidence that the defendant was insane.

How often is the insanity defense?

According to various criminal studies, only about one percent of all felony cases in the United States involve the use of the insanity defense.

Moreover, even when the defense is asserted, it is successful in only about 30 cases every year.

This means that the insanity defense is rarely used and even more rarely successful.

What are some famous cases of the insanity defense?

Here are some of the most famous cases of the insanity defense in the United States:

John Hinckley Jr.
1.John Hinckley Jr.: Hinckley was found not guilty by reason of insanity for the attempted assassination of President Ronald Reagan in 1981.
Andrea Yates
2.Andrea Yates: Yates was found not guilty by reason of insanity for the drowning of her five children in 2001.
Jeffrey Dahmer
3.Jeffrey Dahmer: Dahmer was found sane and guilty of 15 counts of murder in 1992.

4.Ted Bundy: Bundy was found sane and guilty of murder in 1979.

John and Lorena Bobbitt

According to the Legal Information Institute, criminal insanity refers to a mental illness or disease that makes it impossible for a defendant to know they were committing a crime or to understand that their actions are wrong.

A defendant found to be criminally insane can assert an insanity defense.

Insanity functions as a failure of proof defense where the defendant admits to having committed the wrongful act, but claims but argues they are not culpable because of their mental defect prevented them from establishing the required mental state.

Tests to determine if a defendant is criminally insane vary from state to state.

For instance, any jurisdiction that follows the Model Penal Code (MPC) rule looks to see if the defendant lacked both substantial capacity to appreciate the wrongness of their actions and substantial capacity to conform their actions to the law.

Jurisdictions that follow common law tests are primarily split between the M’Naghten Rule and the irresistible impulse test.

Under the former, a party is criminally insane if they lacked the capacity to know they were committing a crime due to a mental defect. Under the latter, a defendant is criminally insane if they lacked total capacity to conform with the law.

In conclusion, the insanity defense is a legal strategy that is rarely used and even more rarely successful.

While it has been controversially applied over the years, various criminal studies have established that it is only used in about one percent of all felony cases in the United States and is successful in only about 30 cases every year.

The burden of proof has also shifted from the prosecutor to the defense in many states, making it more difficult for defendants to prove their insanity.

 

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