美國從七○年代末期起與西方世界廢止死刑潮流背道而馳，加重使用死刑以對付美國日趨嚴重之暴力犯罪，並且是世界上處決最多少年犯的國家。至二十一世紀以後，更成為世界僅存的判處少年犯死刑的國家。顯然迫於國際輿論，美國最高法院終於在二○○五年以5-4票決廢除了少年犯死刑。芮恩奎斯特法庭 (一九八六~二○○五) 判決對十八歲以下少年犯執行死刑是殘酷的刑罰，為美國憲法增修條文第8條與第14條所禁止。本文依序論述傳統英美法對少年犯之定義、少年犯之特別處遇理論、美國處理少年犯罪之對策、美國歷年判處少年犯死刑的狀況。最後詳述廢除少年犯死刑之Roper案的事實與法律問題，並探討該判決之意義及對美國廢止死刑之路的可能影響。

This paper probes differences between the United States and other civilized countries in the use of the death penalty. During the later half of the 20th Century, western European countries started down their path of abolishing the death penalty for all crimes, while the United States, in the late 1970s, began using the death penalty more heavily to combat increasingly violent crime. At the turn of the 21st Century, the US was unique in that it remained not only outside of the two-thirds of countries having abolished the death penalty, but also in executing juveniles in the greatest numbers: The U.S. remains the only country to execute juveniles at the turn of the 21th Century. In 2005, evidently compelled by international indignation, the U.S. Supreme Court struck down the juvenile death penalty in Roper v. Simmons. The Court held that the imposition of the death penalty on juvenile offenders under 18 years of age was “cruel and unusual pun-ishment” and hence forbidden by the Eighth and Fourteenth Amend-ments. This paper examines the definition of juvenile under tradi-tional common law, the theory of special treatment for juvenile de-linquents, the U.S.’s strategy for dealing with juvenile delinquency, and then focuses on the facts and legal issues of Roper, and discusses the significance and the possible impact of this judgment on the prac-tice of the death penalty in the U.S.