A defense asserted by an accused in a criminal prosecution to avoid liability for the commission of a crime because, at the time of the crime, the person did not appreciate the nature or quality or wrongfulness of the acts.(Legal Dictionary)
Is it successful? Only about one-third of the cases are successful.
Is it overused?The defense has been inflamed by the media. There are a very low number of offenders that attempt it.
The M'Naghten rule
The M'Naghten rule is a test for criminal insanity. Under the M'Naghten rule, a criminal defendant is not guilty by reason of insanity if, at the time of the alleged criminal act, the defendant was so deranged that she did not know the nature or quality of her actions or, if she knew the nature and quality of her actions, she was so deranged that she did not know that what she was doing was wrong.
The M'Naghten rule on criminal insanity is named for Daniel M'Naghten, who, in 1843, tried to kill England's prime minister Sir Robert Peel. M'Naghten thought Peel wanted to kill him, so he tried to shoot Peel but instead shot and killed Peel's secretary, Edward Drummond. Medical experts testified that M'Naghten was psychotic, and M'Naghten was found not guilty by reason of insanity”(legal-dictionary).
The Durham Rule
The Durham Rule or "product test" was adopted by the United States Court of Appeals for the District of Columbia Circuit in 1954, in the case of Durham v. U.S. (214 F.2d 862), and states that "... an accused is not criminally responsible if his unlawful act was the product of mental disease or defect". Durham was later overturned in the case U.S. v. Brawner, 471 F.2d 969 (1972). After the 1970s, U.S. jurisdictions have tended to not recognize this argument as it places emphasis on "mental disease or defect" and thus on testimony by psychiatrists and is argued to be somewhat ambiguous.
The "Model Penal Code" Test for Legal Insanity
In response to the criticisms of the various tests for the insanity defense, the American Law Institute (ALI) designed a new test for its Model Penal Code in 1962. Under this test, "a person is not responsible for criminal conduct if at the time of such conduct as a result of mental disease or defect he lacks substantial capacity either to appreciate the criminality of his conduct or to conform his conduct to the requirements of the law."
The Model Penal Code test is much broader than the M'Naghten Rule and the Irresistible Impulse Test. It asks whether defendants have a substantial incapacity to appreciate the criminality of their conduct or to conform their conduct to the law rather than the absolute knowledge required by M'Naghten and the absolute inability to control conduct required by the Irresistible Impulse Test.
The ALI test also requires that the mental disease or defect be a mental diagnosis. In this way, it manages to incorporate elements of all three of its predecessors: the knowledge of right and wrong required by M'Naghten, the prerequisite of lack of control in the Irresistible Impulse Test, and the diagnosis of mental disease and defect required by Durham.
This broad based rule received wide acceptance, and by 1982 all federal courts and a majority of state courts had adopted the ALI test. While some states have since dropped the ALI test, and it no longer applies at the federal level, 18 states still use the ALI test in their definitions of insanity (Findlaw).
Current Application of the Insanity Defense
The question of who has the burden of proof with an insanity defense has been a source of controversy. Before the Hinckley verdict, a majority of states had the burden of proof rest with the state; that is, the prosecutor had to prove that the defendant was not insane. After the Hinckley verdict, the vast majority of states required the defense to prove that the defendant was indeed insane. In states where the burden is on the defense to prove insanity, the defense is required to show either by clear and convincing evidence or by a preponderance of the evidence that the defendant is insane. In states where the burden is still on prosecutors to prove sanity, they are required to prove it beyond a reasonable doubt.
Contrary to uninformed opinion, defendants found not guilty by reason of insanity are not simply released from custody. They are generally committed to mental hospitals where they can be confined for longer than their prison terms would have been. In the case of Jones v. United States, the Supreme Court in 1983 backed this proposition, ruling that the sentence that criminal defendants would have received had they been convicted should have no bearing on how long they could be committed to a mental hospital.
After Hinckley, many states changed their commitment policies to ensure that a defendant found not guilty by reason of insanity would be required to stay in a mental hospital for a certain period of time for evaluation following acquittal. Previously, no time was specified. Also, several states changed the burden of proof for release from the state to defendants.
The federal Insanity Defense Reform Act of 1984, codified at 18 U.S.C. § 17, provides: "It is an affirmative defense to a prosecution under any Federal statute that, at the time of the commission of the acts constituting the offense, the defendant, as a result of a severe mental disease or defect, was unable to appreciate the nature and quality of the wrongfulness of his acts. Mental disease or defect does not otherwise constitute a defense." The act provided that "the defendant has the burden of proving the defense of insanity by clear and convincing evidence." Previously under federal law, the government had the burden of proving sanity.
Guilty but Mentally Ill
Finally, the Hinckley verdict accelerated the adoption of "guilty but mentally ill" verdicts by states. The "guilty but mentally ill" verdict allows mentally ill defendants to be found criminally liable and requires them to receive psychiatric treatment while incarcerated, or, alternatively, to be placed in a mental hospital and then, when they are well enough, to be moved to a prison to serve their sentences. Laws allowing pleas and verdicts of guilty but mentally ill were first adopted in Michigan in 1975, and concurrent with or subsequent to the Hinckley trial were adopted by 12 more states.(Findlaw)
The Insanity Defense Among the States
Four states, including Kansas, Montana, Idaho, Utah, do not allow the insanity defense. In other states, the standards for proving this defense vary widely. The following provides the status of the insanity defense in each jurisdiction:
(facts from Findlaw inserted in graph by Ronlev)
Insanity: Myth or Fact?
Clever and wealthy defendants routinely fake insanity in order to get out of trouble
It is unlikely that many criminal defendants attempt to "fake" insanity because it is very riskyfor any criminal defendant; all chances to plea bargain and contest material facts of the case are lost
According to 1998 opinion polls, 90 % of Americans believe the insanity defense is overused and a ticket to freedom for murderers.
An eight state study funded by the National Institute of Health found 1/2 of those pleading insanity were charged with nonviolent crimes such as property damage and minor felonies
less than 15 % were charged with murder
Killers deemed "Not Guilty by Reason of Insanity" ultimately are turned loose to pose a threat to society at large
Persons successfully pleading insanity spend more time in a mental hospital than they would if found guilty and sentenced to jail
The typical defendant using insanity is a cold-blooded murderer who kills numerous individuals knowing that he can later plead insanity to go free
The typical "Not Guilty by Reason of Insanity" defendant is: (1) an abused wife driven to kill by years of physical abuse; or (2) a depressed individual who kills persons close to him (parents, child, lover)
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