Since the US Supreme Court first addressed the death penalty the 1879 case Wilkerson v. Utah, the Court has struggled with determining the penalty's constitutional boundaries. In 1976 the court held in Gregg v. Georgia that the imposition of the death penalty does not always violate the Eighth Amendment's prohibition against cruel and unusual punishment. The Gregg opinion noted the court's seemingly less-than-consistent application of the Eighth Amendment in death penalty cases. This included the 1972 case of Furman v. Georiga, decided only a few terms prior to Gregg, where only a plurality of the Justices concluded that the penalty was constitutional. The court in Gregg sought to reconcile its position over time by emphasizing how the Eighth Amendment's protections are dynamic and demanded the recognition of evolving public attitude. In this context, the court provided a two-prong inquiry for determining the constitutionality of the death penalty: whether the penalty imposed will avoid causing unnecessary pain and suffering; and whether the penalty is proportional to the severity of the crime.
In Penry v. Lynaugh the court in 1989 decided the constitutionality of the death penalty when applied to a person with intellectual disabilities. The court sought guidance on the issue from state death penalty legislation pertaining to those persons, considering modern legislative efforts the best indicator of society's evolving standards. At the time of Penry, the court found no national consensus on prohibiting the execution of the mentally disabled. In part because of this survey, the court split 5-4 in holding that the execution of persons with intellectual disabilities did not violate the Eighth Amendment. Instead the majority held that a showing of intellectual disability served as a mitigating factor for the sentencing body to consider.
Public consensus on the execution of persons with intellectual disabilities continued to change in the years following the court's decision in Penry. When the issue came before the court again in Atkins v. Virginia in 2002. Justice Stevens, writing for the majority, channeled this consensus in finding the execution of persons with intellectual disabilities unconstitutional as it was cruel and unusual punishment. Justice Stevens addressed the actions by state legislatures to prohibit these executions post-Penry as support for stepping back from that decision. The Atkins decision left unanswered how to determine whether a person had an intellectual disability that precluded application of the death penalty.
On June 20, 2002 the Supreme Court decided Atkins v. Virginia where it ruled sentencing intellectually disabled individuals to death is unconstitutional. The Court held such executions are a form of "cruel and unusual punishment," which is categorically prohibited by the Eighth Amendment. The Atkins decision was silent regarding criteria by which prosecutors could show a defendant's mental capacity.
This set the stage for death row inmate Freddie Lee Hall's challenge to a relevant Florida law. The law allowed for the death penalty in cases where the defendant scored higher than 70 on an I.Q. test; Hall had scored a 71. Accordingly, Hall, who had been convicted of murder, did not qualify for an exception to capital punishment. Florida handed Hall the death sentence. Hall's lawyers contended that because his score of 71 was within the I.Q. test's margin of error, other factors should be permitted to legally establish his intellectual disability. Courts stood by the use of a cutoff I.Q. score and the sentence withstood a series of appeals.
On May 27, 2014 the Supreme Court ruled in Hall v. Florida that the Florida law was unconstitutional. The court reasoned that using the 70 I.Q. cutoff as a hard-and-fast metric of intellectual disability was arbitrary if other considerations were not considered in cases where the defendant scored close to 70. The decision comported with the American Psychological Association's position as stated in its amicus brief [PDF], "a valid diagnosis requires comprehensive assessment of adaptive behavior in conceptual, social, and practical contexts as well as general intellectual functioning."
The court noted that because Hall's score of 71 was within the test's margin of error, his lawyers should have been allowed to present additional evidence to refute the test's finding. Justice Kennedy authored the court's opinion which was joined by Justices Ginsburg, Breyer, Sotomayor and Kagan. Justice Alito filed a dissent which was joined by the Chief Justice, as well as Justices Scalia and Thomas.
Eighteen US states have abolished the death penalty. Three states - Maine, Michigan and Wisconsin - have completely banned the death penalty since the mid-nineteenth century. Fifteen states abolished the death penalty at various points throughout the twentieth and twenty-first centuries.
The remaining 32 states, however, allow the death penalty for certain crimes, but prohibit the punishment from being used on specific population subsets, such as children or persons with intellectual disabilities. When the US Supreme Court ruled that the execution of persons with intellectual disabilities did not violate the US Constitution's Eighth Amendment in the 1989 case, Penry v. Lynaugh, only two states that allowed the death penalty, Georgia and Maryland, had state laws specifically prohibiting the execution of person with mental disabilities.
Following the Penry decision, 16 states outlawed the death penalty for persons with intellectual disabilities. Of those states, six required that a qualified examiner, such as a court-appointed state-licensed psychiatrist or psychologist, evaluate the defendant for intellectual disability. As a result of the Penry decision, the US Congress passed the Violent Crime Control and Law Enforcement Act of 1994, known as the Federal Crime Bill. The law prohibits the federal government from executing a "mentally retarded" person.
After the Supreme Court ruled that executing persons with intellectual disabilities violated the Eighth Amendment in the 2002 decision, Atkins v. Virginia, eight additional states changed their statutes to comply with the decision, bringing the total number of states with statutory bans for death penalty altogether or for defendants with intellectual disabilities to 38.
Many states that amended their death penalty statutes following the Penryor Atkins decisions adopted the term "significantly subaverage general intellectual functioning" to define a determination of mental disability in a defendant. Arkansas code states that there is a rebuttable presumption of mental retardation when the defendant has an IQ of 65 or below. Delaware, Idaho, Kentucky, Nebraska, North Carolina, South Dakota, Tennessee and Washington all define the term as a person with an IQ of 70 or below. Colorado state law specifically declines to name a numerical IQ level to define intellectual disability. For perspective, the average IQ score in the US is 100.
In addition, 18 of the 32 states that allow the death penalty statutorily require that the intellectually disabled defendant have exhibited signs of the disability prior to age 18 or during the defendant's "developmental period." Two states require that the defendant exhibit signs of intellectual disability before age 22. Defendants that exhibit signs of intellectual disability after the age of 18 or 22, or after they have completed their developmental period, are not considered mentally disabled and can be subject to the death penalty if convicted. Nebraska is the only state that currently has the death penalty but does not have an age limit for when signs of intellectual disability must manifest themselves.
Four states that adopted either post-Penry or post-Atkins laws prohibiting the execution of a person with intellectual disability have subsequently abolished the death penalty altogether. New York has had a moratorium on the death penalty since 2007, when the New York State Court of Appeals declared the practice in violation of the state Constitution. New Mexico, Illinois and Connecticut abolished the practice by legislative action in 2009, 2011 and 2012, respectively. Moreover, Maryland - one of the first two states to prohibit the execution of persons with intellectual disabilities - abolished the death penalty by legislative action in 2013.
05/27/2014: Supreme Court found Florida IQ cutoff for executions unconstitutional.
03/03/2014: Supreme Court heard oral arguments on death penalty for intellectually disabled.
05/02/2014: Obama expressed desire to ask AG Holder to investigate death penalty issues.
05/02/2014: UN urged death penalty moratorium in US.
11/02/2010: Georgia rejected clemency for death row inmate who claimed intellectual disability.
06/20/2002: Supreme Court held the execution of mentally retarded persons unconstitutional.
06/26/1989: Supreme Court found that execution of mentally retarded persons did not violate Eighth Amendment prohibition against cruel and unusual punishment.
07/02/1976: Plurality of Supreme Court lifted temporary moratorium on the application of the death penalty in the US....[more]