2002 United States Supreme Court case
Atkins v. Virginia, 536 U.S. 304 (2002), is a case in which the Supreme Court of the United States ruled 6–3 that executing people with intellectual disabilities violates the Eighth Amendment's ban on cruel and unusual punishments, but that states can define who has an intellectual disability. At the time "Atkins" was decided, 18 of the 38 death penalty states exempted mentally disabled offenders from the death penalty.
Twelve years later in "Hall v. Florida" the U.S. Supreme Court narrowed the discretion under which U.S. states can designate an individual convicted of murder as too intellectually incapacitated to be executed.
Background.
The Eighth Amendment standard for cruel and unusual punishment, as stated by the Court in "Weems v United States", "may acquire meaning as public opinion becomes enlightened by a humane justice". The Court expanded this idea of "evolving standards of decency" to death penalty jurisprudence in "Coker v. Georgia" when they decided the death penalty was an unconstitutionally disproportionate punishment for the crime of raping an adult woman. Later, in "Penry v. Lynaugh" the Court found there was insufficient objective evidence of a national consensus against executing the intellectually disabled. 
In 1986, Georgia was the first state to outlaw the execution of intellectually disabled people. Congress followed two years later, and the next year Maryland joined those two jurisdictions. Thus, when the Court confronted the issue in "Penry" in 1989, the Court could not say that a national consensus against executing intellectually disabled people had emerged. Over the next 12 years, 16 more states exempted intellectually disabled people from capital punishment under their laws, bringing the total number of states to 18, plus the federal government.
Case history.
Around midnight on August 16, 1996, following a day spent together drinking alcohol and smoking marijuana, the 18-year-old Daryl Renard Atkins (born November 6, 1977) and his accomplice, William Jones, walked to a nearby convenience store, where they abducted Eric Nesbitt, an airman from nearby Langley Air Force Base. When they realized Nesbitt was only carrying $60, they drove him to a nearby ATM where footage from a surveillance camera showed them forcing Nesbitt to withdraw another $200. The two abductors then drove Nesbitt to an isolated location where Nesbitt was shot eight times and killed as he pleaded for his life.
Jones would not answer police questions without an attorney present. He later claimed that Atkins was the shooter. A deal of life imprisonment was negotiated with Jones in return for his testimony against Atkins. At trial, the jury decided that Jones's version of events was "more coherent and credible", and it convicted Atkins of capital murder. The state sought the death penalty under the statutory aggravating circumstances future dangerousness and vileness.
During the sentencing phase the state sought the death penalty under the statutory aggravating circumstances future dangerousness and vileness. Forensic psychologist Evan Nelson testified that Atkins had an IQ of 59. Nelson said this was "in the range of being mildly mentally retarded". The jury sentenced Atkins to death despite the testimony.
The Supreme Court of Virginia affirmed Atkins's conviction but reversed the death sentence on appeal finding that the sentencing judge had used a verdict form that did not include an option for the jury to impose a life sentence if they found that neither of the aggravating factors had been proven beyond a reasonable doubt.
At the second sentencing hearing psychologist Stanton Samenow testified for the prosecution that Atkins was of "average intelligence at least" based on an outdated test from 1972. Samenow assessed Atkins's vocabulary and knowledge of current affairs, and testified that he understood cause and effect, and could use relatively complex words like orchestra and decimal. Acknowledging that Atkins's academic performance was "by and large" terrible, Samenow said meeting academic requirements did not hold the defendant's attention. The prosecution also presented testimony about Atkins's criminal history which began in early adolescence and included over a dozen prior felony convictions for robbery, larceny and burglary.
Atkins was sentenced to death a second time. The sentence was affirmed by the Virginia Supreme Court based on a prior Supreme Court decision, "Penry v. Lynaugh". Justice Cynthia D. Kinser authored the five-member majority. Justices Leroy Rountree Hassell Sr. and Lawrence L. Koontz Jr. authored dissenting opinions.
The United States Supreme Court granted certiorari "because of the gravity of the concerns expressed by the dissenters" and "in light of the dramatic shift in the state legislative landscape that has occurred in the past 13 years." The Court heard oral arguments in the case on February 20, 2002.
Supreme Court.
Majority opinion.
When "Penry" was decided only two states exempted the intellectually disabled from death penalty eligibility. That number had increased to 18 by the time "Atkins" was decided. Although 18 was not a majority of the 38 death penalty states, the Court said the "consistency of direction of change" toward a prohibition on the execution of intellectually disabled people and the relative rarity of such executions, supported their finding that a "national consensus has developed against it." This determination was accompanied by a footnote stating that a "broader social and professional consensus" provides "additional evidence" of a national consensus. The dissenters objected to broadening the analysis to include this "additional evidence".
The Eighth Amendment requires that criminal punishments are proportionate. Concurring in "Penry v. Lynaugh", Justice William Brennan wrote that the proportionality of a punishment depended on the severity of the injury caused and the defendant's moral culpability. In "Coker v. Georgia" the Court explained that punishments are unconstitutionally disproportionate if they don't advance legitimate penological purposes or are disproportionate to the severity of the crime. 
The "relationship between mental retardation and the penological purposes served by the death penalty" justifies a conclusion that executing intellectually disabled people is cruel and unusual punishment that the Eighth Amendment should forbid. In other words, unless it can be shown that executing the intellectually disabled serves the recognized penological goals of retribution and deterrence, doing so is nothing more than "purposeless and needless imposition of pain and suffering", making the death penalty cruel and unusual in those cases. 
Justice Stevens relied on clinical diagnostic criteria to conclude that people with mental retardation "have diminished capacities to understand and process information, to communicate, to abstract from mistakes and learn from experience, to engage in logical reasoning, to control impulses, and to understand the reactions of others". The "Atkins" Court said cognitive and behavioral impairments not only diminished moral culpability for impulsive conduct, they also made it less likely that defendants would be deterred by the death penalty:
Yet it is the same cognitive and behavioral impairments that make these defendants less morally culpable—for example, the diminished ability to understand and process information, to learn from experience, to engage in logical reasoning, or to control impulses—that also make it less likely that they can process the information of the possibility of execution as a penalty and, as a result, control their conduct based upon that information
As for retribution, society's interest in seeing that a criminal get his "just deserts" means that the death penalty must be confined to murders that reflect "a consciousness materially more 'depraved' than the average murderer. The goal of retribution is not served by imposing the death penalty on a group of people with a significantly lesser capacity to understand why they are being executed.
Because intellectually disabled people cannot communicate with the same sophistication as the average offender, there is a greater likelihood that their deficiency in communicative ability will be interpreted by juries as a lack of remorse for their crimes. They typically make poor witnesses and the presentation of mitigating evidence of intellectual disability can be a "two edged sword that may enhance the likelihood that the aggravating factor of future dangerousness will be found by the jury". Thus, there is a greater risk that the jury may impose the death penalty despite the existence of mitigating evidence. 
In light of the "evolving standards of decency" that the Eighth Amendment demands, the fact that the goals of retribution and deterrence are not served as well in the execution of intellectually disabled people, and the heightened risk that the death penalty will be imposed despite the mitigating circumstances, the Court concluded that the Eighth Amendment forbids the execution of intellectually disabled people, leaving implementation to the states.
Dissents.
Dissenting opinions were written by Justices Antonin Scalia, Clarence Thomas and Chief Justice William Rehnquist. The Chief Justice said that "foreign laws, the views of professional and religious organizations, and opinion polls" were not "objective indicia of contemporary values" under the Court's existing precedents.
Justice Antonin Scalia said there was no clear national consensus to exempt the intellectually disabled from death penalty eligibility and agreed with the Chief Justice that the "amici" cited to provide "additional evidence" of a national consensus were irrelevant. Scalia commented in his dissent that "seldom has an opinion of this court rested so obviously upon nothing but the personal views of its members."
Reaction.
Mental health professionals generally approved of the decision. The Executive Director of the American Association on Mental Retardation said it was "an important day for disability advocates and for our country." Many mental health organizations filed "amici" briefs in support of "Atkins". The American Psychiatric Association argued that mental health professionals can make an "objective determination" of mental retardation "using time-tested instruments and protocols with proven validity and reliability".
Douglas Mossman was critical of the implications of the clinical analysis underlying the "Atkins" decision. The Court's basic acceptance of the claim that moral capacity is causally related to psychiatric diagnoses stigmatizes mentally disabled persons, Mossman said, by implying that they are less morally resonsible than non-disabled persons. By creating culpability-based exemptions for death penalty eligibility the "Atkins" decision will force courts to decide whether other psychiatric disabilities similarly qualify.
Subsequent developments.
In the Supreme Court.
Twelve years after its "Atkins" decision the U.S. Supreme Court narrowed in "Hall v. Florida" (2014) the discretion of states to implement the "Atkins" ruling. "Hall" was the first case to consider a state-imposed limitation on "Atkins"-eligibility, holding that a state could not require an IQ score of 70 or below to make an "Atkins" claim presenting evidence of adaptive impairment.
In "Moore v. Texas" (2017) the Supreme Court found that "the lay perceptions" advanced by the "wholly non-clinical" "Briseno" factors that were implemented by the Texas Court of Criminal Appeals after "Atkins" "created an unacceptable risk that persons with intellectual disability wtill be executed". The seven "Briseno" factors included questions like "can the person hide facts or lie effectively in his own or others' interests" or if the crime required "forethought, planning, and complex execution of purpose".
On remand.
When Evan Nelson, who measured Atkins's IQ at 59 during the trial, retested Atkins after the case was remanded back to Virginia courts, Atkins scored above Virginia's cut-off score 70. Nelson told jurors that Atkins was "in much better intellectual shape...due to the stimulation he had received while in confinement" communicating with his attorneys.
Prosecutors maintained that the new scores confirmed that Atkins had never been intellectually disabled. They noted the circumstances of the crime including his ability to load and aim a gun, recognize an ATM card, direct the victim to withdraw cash and attempt to hide his involvement in the robbery from police were inconsistent with being "truly mentally retarded". 
The victim's mother was skeptical that Atkins was the right case to develop the law stating that "he's probably not the brightest bulb in the pack but I don't think he's mentally retarded." Defense attorneys described the case as "right on the edge".
In January 2008, Circuit Court Judge Prentis Smiley, who was revisiting the matter of whether Atkins was mentally disabled, received allegations of prosecutorial misconduct. Those allegations, if true, would have authorized a new trial for Atkins. After two days of testimony on the matter, Smiley determined that prosecutorial misconduct had occurred. At that juncture, Smiley could have vacated Atkins's conviction and ordered a new trial. Instead, Smiley determined the evidence was overwhelming that Atkins had participated in a felony murder and commuted Atkins's sentence to life in prison.
Prosecutors sought writs of mandamus and prohibition in the Virginia Supreme Court on the matter, claiming that Smiley had exceeded his judicial authority with his ruling. On June 4, 2009, the Virginia Supreme Court, in a 5-2 decision authored by Chief Justice Leroy R. Hassell Sr., ruled