Justice Anthony Kennedy (majority): “Respondent and his amici have submitted, and petitioner does not contest, that only seven countries other than the United States have executed juvenile offenders since 1990: Iran, Pakistan, Saudi Arabia, Yemen, Nigeria, the Democratic Republic of Congo, and China. Since then each of these countries has either abolished capital punishment for juveniles or made public disavowal of the practice. Brief for Respondent 49 to 50. In sum, it is fair to say that the United States now stands alone in a world that has turned its face against the juvenile death penalty….

“It is proper that we acknowledge the overwhelming weight of international opinion against the juvenile death penalty, resting in large part on the understanding that the instability and emotional imbalance of young people may often be a factor in the crime…. The opinion of the world community, while not controlling our outcome, does provide respected and significant confirmation for our own conclusions.

“Over time, from one generation to the next, the Constitution has come to earn the high respect and even, as Madison dared to hope, the veneration of the American people. See The Federalist No. 49, p. 314 (C. Rossiter ed. 1961). The document sets forth, and rests upon, innovative principles original to the American experience, such as federalism; a proven balance in political mechanisms through separation of powers; specific guarantees for the accused in criminal cases; and broad provisions to secure individual freedom and preserve human dignity. These doctrines and guarantees are central to the American experience and remain essential to our present-day self-definition and national identity. Not the least of the reasons we honor the Constitution, then, is because we know it to be our own. It does not lessen our fidelity to the Constitution or our pride in its origins to acknowledge that the express affirmation of certain fundamental rights by other nations and peoples simply underscores the centrality of those same rights within our own heritage of freedom.”

Justice Antonin Scalia (dissent): “The Court thus proclaims itself sole arbiter of our Nation’s moral standards—and in the course of discharging that awesome responsibility purports to take guidance from the views of foreign courts and legislatures. Because I do not believe that the meaning of our Eighth Amendment, any more than the meaning of other provisions of our Constitution, should be determined by the subjective views of five Members of this Court and like-minded foreigners, I dissent….

More fundamentally, however, the basic premise of the Court’s argument—that American law should conform to the laws of the rest of the world—ought to be rejected out of hand. In fact the Court itself does not believe it. In many significant respects the laws of most other countries differ from our law—including not only such explicit provisions of our Constitution as the right to jury trial and grand jury indictment, but even many interpretations of the Constitution prescribed by this Court itself. The Court-pronounced exclusionary rule, for example, is distinctively American.”