years later, and the next year Maryland joined these 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 twelve years, nineteen more states exempted intellectually disabled people from capital punishment under their laws, bringing the total number of states to twenty-one, plus the federal government. While there are 50 states, 19 don't allow the death penalty under any circumstance, making 21 out of 31 a clear majority of the death penalty states. In light of the "consistency of direction of change" toward a prohibition on the execution of intellectually disabled people, and the relative rarity of such executions in states that still allow it, the Court proclaimed that a "national consensus has developed against it." The Court, however, left it to individual states to make the difficult decision regarding what determines intellectual disability. Also, 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 promotes the 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. Being intellectually disabled means that a person not only has substandard intellectual functioning but also significant limitations in adaptive skills such as communication, self-care, and self-direction. These deficiencies typically manifest before the age of eighteen. Although they can know the difference between right and wrong, these deficiencies mean they have a lesser ability to learn from experience, engage in logical reasoning, and understand the reactions of others. This means that inflicting the death penalty on one intellectually disabled individual is less likely to deter other intellectually disabled individuals from committing crimes. As for retribution, society's interest in seeing that a criminal get his "just desserts" means that the death penalty must be confined to the "most serious" of murders, not simply the average murder. The goal of retribution is not served by imposing the death penalty on a group of people who have a significantly lesser capacity to understand why they are being executed. Because intellectually disabled people are not able to communicate with the same