Reasoning of the court

The two briefs argued that, because of their immature development and severe psychopathology, juvenile offenders should not be subject to the death penalty. The briefs pointed out that, relative to adults, teenagers are impulsive and lacking in judgment. They are thus unlikely to carefully consider the consequences of their behavior, and the death penalty has no value as a deterrent for them. According to the court, "the likelihood that the teenage offender has made the kind of coldblooded, cost-benefit analysis that attaches any weight to the possibility of execution is virtually nonexistent"; the court added, "It is fanciful to believe that a 15 year old would be deterred by the knowledge that a small number of persons his age have been executed during the 20th century". The second argument is that violent juvenile offenders are even more impaired than normal adolescents-having as a rule been the victims of abuse and other noxious influences. As a consequence, they suffer from neurologic and mental illnesses that impair their judgment and thinking even beyond the immature functioning of normal adolescents. As stated in the brief, "Adolescents who commit murder suffer from serious psychological and family disturbances which exacerbate the already existing vulnerabilities of youth"(http://caselaw.lp.findlaw.com/cgi-bin/getcase.pl?court=US&vol=487&invol=815)