Why People with Intellectual Disability Are Exempt from the Death Penalty

In 2002, the Supreme Court held in Atkins v. Virginia that it would be cru­el and unusu­al pun­ish­ment to sen­tence peo­ple with intel­lec­tu­al dis­abil­i­ty to death. (The Court used the cor­rect ter­mi­nol­o­gy at the time, refer­ring to indi­vid­u­als with ​“men­tal retar­da­tion.”) At the time, 18 states exempt­ed this group from cap­i­tal pun­ish­ment, and the Court deter­mined that the ​“leg­isla­tive judg­ment reflects a much broad­er social and pro­fes­sion­al con­sen­sus” that exe­cut­ing indi­vid­u­als with intel­lec­tu­al dis­abil­i­ty was an exces­sive pun­ish­ment not in accord with our stan­dards of decen­cy. Justice Stevens, deliv­er­ing the opin­ion of the Court, wrote:

Mentally retard­ed per­sons fre­quent­ly know the dif­fer­ence between right and wrong and are com­pe­tent to stand tri­al, but, by def­i­n­i­tion, they 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 oth­ers’ reac­tions. Their defi­cien­cies do not war­rant an exemp­tion from crim­i­nal sanc­tions, but dimin­ish their personal culpability.

The Court doubt­ed that the jus­ti­fi­ca­tions under­pin­ning the death penal­ty – ret­ri­bu­tion and deter­rence – applied to intel­lec­tu­al­ly dis­abled offend­ers. Justice Stevens wrote:

As to ret­ri­bu­tion, the sever­i­ty of the appro­pri­ate pun­ish­ment nec­es­sar­i­ly depends on the offend­er’s cul­pa­bil­i­ty. If the cul­pa­bil­i­ty of the aver­age mur­der­er [that is, a mur­der­er whose crime involves no spe­cial aggra­vat­ing cir­cum­stances] is insuf­fi­cient to jus­ti­fy impo­si­tion of death, the less­er cul­pa­bil­i­ty of the men­tal­ly retard­ed offend­er sure­ly does not mer­it that form of ret­ri­bu­tion. As to deter­rence, the same cog­ni­tive and behav­ioral impair­ments that make men­tal­ly retard­ed defen­dants less moral­ly cul­pa­ble 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.

The Court cit­ed the high­er prob­a­bil­i­ty of inac­cu­rate fac­tu­al deter­mi­na­tions of guilt and indi­vid­ual cul­pa­bil­i­ty due to the increased poten­tial that defen­dants with intel­lec­tu­al dis­abil­i­ty would ​“unwit­ting­ly con­fess to crimes they did not com­mit.” For exam­ple, Earl Washington, who had an IQ of 69, faced exe­cu­tion after con­fess­ing to a crime he did not com­mit. In 1983, police con­vinced Washington to make a state­ment con­cern­ing the 1982 rape and mur­der of a woman in Culpepper, VA. The state­ments were used against him, and in 1984 he was con­vict­ed and sen­tenced to death. Sixteen years lat­er, DNA tests con­firmed that Washington was inno­cent and he received an absolute pardon.

The Atkins opin­ion also sug­gest­ed that “[m]entally retard­ed defen­dants may be less able to give mean­ing­ful assis­tance to their coun­sel and are typ­i­cal­ly poor wit­ness­es, and their demeanor may cre­ate an unwar­rant­ed impres­sion of lack of remorse for their crimes.”