Final answer:
True. The death penalty may not be imposed upon any person who was under 18 when the crime was committed.
Step-by-step explanation:
The answer to the question is True. According to the Supreme Court rulings, the death penalty may not be imposed upon any person who was under 18 when the crime was committed. The statement is true: under no circumstances may the death penalty be imposed upon any person who was under 18 when the crime was committed. This ruling is supported by the Supreme Court decision in Roper v. Simmons, which held that it is unconstitutional to execute juvenile offenders who were under the age of 18 at the time of their crimes. Such a decision reflects the Court's perspective on the Eighth Amendment's prohibition against cruel and unusual punishment and recognizes the inherent differences between juvenile and adult offenders in terms of moral culpability and decision-making capabilities.