"The court thus proclaims itself sole arbiter of our nation's moral standards."

So says Justice Scalia, dissenting from the Supreme Court's decision invalidating the death penalty for those who were under 18 years old when they committed their crimes. But the Court setting a minimal standard is not making itself the sole arbiter of morality, since a state could express stronger disapproval of the death penalty by, for example, outlawing it altogether.

UPDATE: Here's my separate post on the debate about the use of international opinion in the case.