In the Penry case, the Court rejected the argument that imposing the death penalty on mentally retarded defendants violates the eighth amendment's prohibition of cruel and unusual punishment. Similarly, the Stanford decision rejected the argument that the eighth amendment prohibited death sentences for the two minors convicted of murder. Thus, these decisions overturned almost 20 years of decisions requiring that the death penalty, because of its severity and finality, be used only when it serves a valid penal purpose that a lesser sentence could not. The court failed to give proper weight to evidence that mentally retarded offenders are unable to engage in the "cold calculus" required to deter criminals and that minors do not engage in the consideration of mortality that is central to the deterrent rationale. Footnotes