What are the scariest words in constitutional law these days? "Justice Kennedy delivered the opinion of the Court."

Earlier this term, Kennedy wrote the 5-4 opinion that extended habeas corpus rights to foreigners captured abroad and held on foreign soil. Such a right had never been granted in American history. This was a victory for the terrorists held at Camp Delta in Guant namo Bay, Cuba, who now can challenge their detention in federal courts.

For his next trick, Kennedy wrote last week another 5-4 opinion declaring the death penalty for child rapists unconstitutional. In so doing, the Court invalidated statutes in six states and quashed similar laws under consideration in five other states. Chalk this up as an emphatic defeat for constitutional self-government and a victory for petitioner Patrick Kennedy, the New Orleans man who in 1998 brutally raped his then-8-year-old stepdaughter. Kennedy (no relation to our justice) was sentenced to death in 2003. Now he'll live.

You don't have to support the death penalty in order to find the Court's decision appalling. The reasoning is terribly flawed. The intellectual backflips Justice Kennedy performed in his opinion would be impressive if they weren't so offensive to constitutionalist sensibilities.

First, the justice argued that "there is a national consensus against capital punishment for the crime of child rape." How did he determine this? By observing that only six states have statutes allowing the death penalty in such cases. "By contrast, 44 States have not made child rape a capital offense." But this judicial beancounting

Kennedy acknowledged that "in the last 13 years there has been change towards making child rape a capital offense." He noted that "this is evidenced by six new death penalty statutes, three enacted in the last two years." At the time of the ruling, five additional states were considering allowing the death penalty in cases of child rape. Some might see here evidence of a shift in public opinion. Not Kennedy. "That five States may have had pending legislation authorizing death for child rape is not dispositive," he wrote, "because it is not this Court's practice...to find contemporary norms based on legislation proposed but not yet enacted." Better to just make up the norms instead.

Next, Kennedy concluded that the "death penalty is not a proportional punishment for the crime of child rape." Why not? Here the justice broke out his well-worn "evolving standards of decency." "There is a distinction," he wrote, "between intentional first-degree murder on the one hand and nonhomicide crimes against individuals, even including child rape, on the other." Of course there is. Every type of crime is distinct. That is why we elect legislatures to write statutes that determine which punishments fit which crimes. Is it really so indecent of some legislatures to think the rape of an 8-year-old merits the same sanction as homicide?

Kennedy admits that "rape has a permanent psychological, emotional, and sometimes physical impact on the child....We cannot dismiss the years of long anguish that must be endured by the victim of child rape." But dismiss them is exactly what the majority did when it decided by fiat that there is an "incongruity between the crime of child rape and the harshness of the death penalty."