“Seldom,” writes Justice Scalia, dissenting from the Supreme Court’s decision to rule unconstitutional all executions of the mentally retarded, “has an opinion of this Court rested so obviously upon nothing but the personal views of its members.” To see why, one need but cast one’s peepers over Justice Stevens’ majority opinion, which was joined by five of the other justices. Rarely have the principles of federalism and strict construction of the Constitution been more carfuffled. While we have sympathy with the notion that those too severely retarded to know right from wrong should be spared — New York already bans the execution of such persons — yesterday’s decision has all the marks of being not about how to mete justice to mentally retarded persons but about moving forward the cause of an outright ban on the death penalty in all cases.

The nub of Justice Stevens’ argument is that the execution of the mentally retarded must be considered “cruel and unusual punishment” under the Eight Amendment in our Bill of Rights. This is an old saw regarding the death penalty in general. It falls under the rubric of Court liberals’ concept of a “living Constitution” — one that changes and molds to the evolving mores of American society. Since executions were not only widely accepted during the founding of America, but also specifically contemplated in the text of the Bill of Rights, opponents of the death penalty have been forced to argue that “cruel and unusual” can be defined anew by each generation. If the Constitution is a living document, the argument goes, the Court can stand on the pedestal of public opinion to change the Constitution without the public ever having to soldier through the amendment process.

Justice Stevens managed, remarkably, to divine the opinion of the American people — more efficiently, apparently, than their elected state legislatures. How did he accomplish this feat? Partly, he relied on that revered constitutional tool, the opinion poll. He also pulled another remarkable trick from under his robe. Unable to claim that a majority of states bar the execution of the mentally retarded — since only 18 of the 38 states that have a death penalty exempt them — Justice Stevens asserts that, “It is not so much the number of these States that is significant, but the consistency of the direction of change.” Retorts the Great Scalia in a devastating riposte: “Given that 14 years ago all the death penalty statutes included the mentally retarded, any change … was bound to be in the one direction the Court finds significant enough to overcome the lack of real consensus.”

The issue of whether the mentally retarded should be executed is a complex one. Aside from the question of moral culpability, there is also the added complication that mental retardation is observed on a sliding scale. The determination of whether an impaired person should be put to death is necessarily one that must be made on a case by case basis. In Atkins v. Virginia, two juries made the same determination on separate occasions, once at trial and once on resentencing. The juries listened to witnesses, family members, and experts, and made, as was their duty, a decision about the fate of Daryl Atkins, a mildly retarded man who brutally murdered an airman from Langley Air Force Base. Now, juries in 20 states have had their decisions made for them. The people in those states have been overruled by six justices in Washington. We’ll see what the opponents of the death penalty say when the direction of change shifts.