In Atkins v. Virginia, the Supreme Court held that the execution of individuals with intellectual disability violated the Eighth Amendment to the United States Constitution. When creating the categorical exemption in Atkins the Court recognized that without the exemption juries might consider intellectual disability to be a two-edged sword: "it may diminish his blameworthiness for his crime even as it indicates that there is a probability that he will be dangerous in the future." The Supreme Court also held that the Eight Amendment limits the extent that states can impose the most serious punishments on juveniles, including certain forms of life without parole. This dissertation examines whether the two-edged nature of intellectual disability or young age may influence other decisions in the justice system that ultimately affect criminal sentences. The first Chapter examines whether parole board decisions in South Carolina cause some juvenile offenders to serve de facto life without parole sentences. Chapter Two explores whether mental health experts may be influenced by the facts of a heinous crime or their beliefs about the death penalty when they diagnose intellectual disability in death penalty cases. Chapter Three examines the post-conviction relief process for people appealing their death sentences because they are categorically exempt from the death penalty. It argues that the more-forgiving procedural exemptions applied in claims of innocence should be applied in claims of ineligibility for the death penalty.