Diminished capacity
Diminished capacity is a legal defense that asserts a defendant should not be held fully criminally accountable for their actions due to impaired mental functions, often related to developmental disabilities. Unlike the insanity defense, which involves a diagnosis of mental illness that affects a person's ability to understand right from wrong, diminished capacity involves conditions that may not meet the criteria for insanity but still affect cognitive functioning. This defense is primarily used to argue for reduced culpability rather than a complete acquittal, typically resulting in lesser charges.
The legal landscape surrounding diminished capacity has evolved, particularly with landmark rulings such as the U.S. Supreme Court's decision in Atkins v. Virginia, which prohibits the execution of individuals with mental retardation, recognizing their diminished capacity for understanding. Additionally, the concept of diminished capacity intersects with discussions about juvenile offenders, as developmental psychologists highlight that younger individuals may lack the cognitive maturity to grasp the implications of their actions, influencing their prosecution.
However, the application of diminished capacity can be complex, with varying legal interpretations and restrictions, particularly concerning the role of substance abuse as a mitigating factor. Some states have even moved to abolish both the insanity and diminished capacity defenses altogether, reflecting ongoing debates about accountability and mental health in the legal system.
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Diminished capacity
SIGNIFICANCE: Diminished capacity is a significant legal defense in crimes involving developmentally disabled persons.
Diminished capacity is a defense tactic wherein defendants argue that although they did break the law, they should not be held criminally accountable for doing so because of their impaired, or diminished, mental functions. This defense is invoked in attempt to reduce a defendant’s culpability.
The diminished capacity defense is somewhat similar to that of insanity, but in diminished capacity cases defendants have not been diagnosed with mental illnesses that restrict their abilities to know right from wrong. The insanity defense was first recognized in 1843 in Great Britain when the delusional Daniel McNaghten killed the secretary to Prime Minister Robert Peel because McNaghten believed that the government was plotting against him. He was acquitted on the grounds of insanity.
In 2001, the Michigan Supreme Court ruled, in People v. Carpenter , that “evidence of mental incapacity less than insanity cannot avoid or reduce criminal responsibility by negating specific intent. Rather, only mental illness constituting insanity can negate intent, and mental illness or mental retardation not rising to insanity can result in entitlement to psychiatric treatment during incarceration.”
The best-known examples of diminished mental capacity include the developmentally delayed condition sometimes called mental retardation. Pleading diminished capacity is not likely to result in a finding of not guilty but rather would be considered as a mitigating circumstance, resulting in the defendant being charged with a lesser offense. In some cases the diminished capacity is taken into consideration at sentencing.
In 1989, the American Bar Association promulgated a policy position recommending that the practice of execution of developmentally delayed persons be abolished. On June 20, 2002, the U.S. Supreme Court, in Atkins v. Virginia , held that “it is a violation of the Eighth Amendment ban on cruel and unusual punishment to execute death-row inmates with mental retardation.” This landmark decision resulted in a moratorium on the execution of mentally disabled inmates.
The issue of chronological age as diminished capacity is controversial. In response to increasing violent criminal behavior by adolescents, most states have increased the number of juvenile offenders waived to adult court for prosecution. States have reduced the age for waiver of jurisdiction and established policies pertaining to mandatory waiver for specific crimes.
Developmental psychologists agree that preadolescent children lack the cognitive ability of abstract thinking and, consequently, cannot truly appreciate the seriousness of their conduct. The situation is exacerbated with adolescents who have lower than average intelligence. Chronologically, their age may qualify them for waiver; however, their mental age is below their chronological age due to limited intelligence.
Defense attorneys have attempted to extend the legal concept of diminished capacity to include the influence of alcohol and drugs as mitigating circumstances. These defenses to crime are not successful and are commonly restricted by law. Some states have passed legislation that abolishes both the insanity defense and the defense of diminished capacity.
Bibliography
Conley, R, R. Luckasson, and G. N. Bouthilet. The Criminal Justice System and Mental Retardation: Defendants and Victims. Baltimore: Brookes, 1992.
Felthous, Alan R. "Rational Capacity and Criminal Responsibility in the USA." International Journal of Law Psychiatry, vol. 83, July-Aug. 2022, doi.org/10.1016/j.ijlp.2022.101809. Accessed 25 June 2024.
Ferguson, Danielle. "Mich. Chief Justice Pushed for Diminished Capacity Defense." Law360, 17 July 2024,
www.law360.com/articles/1699898/mich-chief-justice-pushes-for-diminished-capacity-defense. Accessed 25 June 2024.
Reed, E. F. The Penry Penalty: Capital Punishment and Offenders with Mental Retardation. Lanham, Md.: University Press of America, 1993.