Why are individuals with intellectual disabilities not allowed to be sentenced to death?

The United States Supreme Court has ruled that it is unconstitutional to impose the death penalty on individuals with intellectual disabilities, based on the Eighth Amendment's prohibition against "cruel and unusual punishments." The court has recognized that people with intellectual disabilities may face limitations in intellectual functioning and adaptive behavior, which often results in significant impairments in their ability to understand and process information, make decisions, and engage in social interactions.

Executing individuals with intellectual disabilities was deemed cruel and unusual punishment because they may have diminished moral culpability for their actions due to these impairments. Additionally, they may be less capable of understanding the consequences of their behavior or participating effectively in their defense during the legal process. Therefore, the court has recognized the need to protect their rights and provide a different approach to criminal punishment.