ATLANTA -- The Supreme Court will be asked today to decide "whether the execution of mentally retarded individuals convicted of capital crimes violates the Eighth Amendment." The case involves Daryl Atkins, who was sentenced to die in Virginia for a murder and kidnapping in 1996. Mr. Atkins has an I.Q. score of 59, below the score of 70 that is commonly used to identify mental retardation.
The court will consider whether the intellectual limitations caused by mental retardation are so substantial that executing the retarded is punishment that is "cruel and unusual" and unconstitutionally disproportionate to the culpability of mentally retarded offenders. In 1988, the court ruled that imposing the death penalty upon defendants who were younger than 16 when they committed their crimes violated the Eighth Amendment. The court cited teenagers' "inexperience, less education, and less intelligence" as reasons "their irresponsible conduct is not as morally reprehensible as that of an adult."
In death penalty jurisprudence, the key questions often are not about guilt or innocence, but instead whether a person's culpability is great enough to warrant the extraordinary penalty of death. We recently completed a study that sheds light on the intellectual capacities of mentally retarded people to understand even the most common legal concepts. Our results support the idea that mentally retarded people as a class, like those younger than 16 as a class, lack sufficient culpability to permit the use of death penalty.
Researchers in the study tested some four dozen mentally retarded subjects to determine if they could understand the Miranda warnings, which advise suspects that they have a right to remain silent and that any statements they make may be used against them. The performance of the mentally impaired people was then compared with that of a control group of people of average or above average intelligence.
The results were both striking and discouraging. The great majority of the mentally retarded subjects failed to understand that the words "You have a right to remain silent" mean that a person does not have to speak. This was true even when the vocabulary of the Miranda warnings was simplified. They also failed to comprehend the consequences of confessing. Most of these subjects did not understand that the defense attorney is not the defendant's adversary. In contrast, the vast majority of the non-disabled control group understood the individual words, the warnings and their legal significance.
The impact of retardation on participation in the legal process is substantial. Mentally retarded people are more likely than people with average I.Q.'s to confess, and they are far more likely to confess to crimes they did not commit.
When mentally retarded suspects waive their Fifth Amendment rights and confess, their waivers are not, in all likelihood, "knowing and intelligent," as the Supreme Court's decisions long have required.
There is a growing national consensus that the death penalty — even if appropriate in some circumstances — may nonetheless be an excessive punishment that violates the Eighth Amendment when inflicted upon those who lack the capacity to evaluate the consequences of their conduct. Eighteen states of the 38 that allow capital punishment have enacted laws prohibiting the execution of the mentally retarded for this reason.
The Supreme Court has suggested that the death penalty could only be imposed on "a fully rational, choosing agent." A person intellectually incapable of understanding the meaning of the most basic warnings given to defendants in the criminal justice system does not meet this standard. Justice is not achieved by executing people who cannot comprehend the most rudimentary legal concepts.
Morgan Cloud and George Shepherd are professors at the Emory University School of Law.
