In Penry v. Lynaugh and Stanford v. Kentucky, the Supreme Court decided issues concerning the capital punishment of mentally retarded and 16- and 17-year-old murders and sentencing juries' consideration of mitigating evidence under Texas' death penalty statutes. The division among the justices in these cases reflects disagreements about fundamental principles of death penalty doctrine that have evolved since 1972, when Furman v. Georgia was decided. One wing of the Court (Scalia, Kennedy, White, and Rehnquist) advocates a positivist/deferential approach, which holds that the Court's determination of whether the death penalty is an excessive punishment for specific offenses and offenders is a function of the weight of enabling legislation and the implementation of that legislation by judges and juries. The other branch of the Court (with O'Connor as a swing vote) uses a normative approach in analyzing eighth amendment claims, maintaining that the judiciary has an active role in interpreting the cruel-and-unusual-punishments clause that goes beyond merely assessing popular public attitudes about the death penalty. The positivist/deferential approach would surrender to public opinion the Court's function of defining and protecting eighth amendment standards. 151 notes. (Author abstract modified)