In 1989, the United States Supreme Court decided in Penry v Lynaugh, 492 U.S. 302 (1989), that the execution of a mentally disabled offender was not 'cruel and unusual punishment' under the Eighth Amendment to the U.S. Constitution.In 1996, eighteen year old Daryl Renard Atkins and an accomplice kidnapped a convenience store customer, drove him to his ATM machine demanding he withdraw money for them, and then drove him to an isolated location where they shot him eight times, killing him. At the criminal murder trial of Atkins, expert testimony established Atkins' IQ was 59.Atkins was sentenced to death despite this evidence of his mental disability. Appeals made their way eventually to the United States Supreme Court. By that time, 21 States had outlawed the death penalty under any circumstance, and additional States outlawed the death penalty of an intellectually disabled individual. In its opinion published in 2002, the Supreme Court held that executing people with intellectual disabilities did violate the Eighth Amendment. (Atkins v Virginia, 536 U.S. 304 (2002).) The Court stated: "...[T]he Eighth Amendment should be interpreted in light of the 'evolving standards of decency that mark the progress of a mature society." It further stated: "...[U]nless it can be shown that executing the mentally retarded 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 mentally retarded 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."

QUERY:Explain how these two cases present an example of 'constitutional relativity' (also referred to in your textbook as 'Legal Realism')