The immediate outcome of the Supreme Court’s 5-to-4 decision in Roper v. Simmons is reason enough to celebrate: With one stroke it set aside seventy-two death sentences imposed for crimes committed by teenagers and categorically banned capital punishment for offenders under 18. The Court’s powerful majority opinion–all the more notable because it was written by Reagan appointee Anthony Kennedy–adds momentum to the narrowing of capital sentences and diminishing number of executions in the United States. Justice Kennedy’s opinion explicitly acknowledges teenagers’ universal “vulnerability and comparative lack of control over their immediate surroundings,” elaborated with a humane and scientific recognition of developmental psychology, too long absent from the death penalty debate.

But the significance of Roper v. Simmons goes far beyond those seventy-two cases, thanks to Justice Kennedy’s unapologetic embrace of international human rights standards. Noting that the United States was the only nation left routinely imposing capital punishment on teens, Kennedy invoked “the overwhelming weight of international public opinion”: a judicial glove smacked across the faces of Antonin Scalia and the whole original-intent crowd, so full of disdain for the Court’s recent embrace of evolving global standards in other death penalty cases and in gay rights cases. Considering the international context of human rights, Kennedy wrote pointedly, “does not lessen our fidelity to the Constitution or our pride in its origins.”

Since only a handful of nations still maintain capital punishment under any circumstances, the implication of Kennedy’s remark for future death penalty cases should not be underestimated. The Court’s growing willingness to listen to briefs from the EU and retired American diplomats should cause the Bush Administration particular uneasiness as more and more cases from the “war on terror” make their way up the docket: “The overwhelming weight of international public opinion” applies as thoroughly to torture and imprisonment without charge.

Does Roper v. Simmons presage abolition of capital punishment? It certainly adds momentum, as does the recent reversal of death penalty sentiment in New York’s legislature. But capital punishment’s shrewdest defenders–among them, perhaps, Justice Kennedy himself–now consciously seek to narrow the death penalty in order to save it. Justice Sandra Day O’Connor frets aloud about the poor quality of capital representation, and no less an execution-friendly President than George W. Bush now promotes increased spending for death-row lawyers. This isn’t because of some new love of civil rights. The right needs the public clamor stirred by executions. So the smarter defenders of state killing have a strategy to dampen public doubt: join in sweeping from the table those cases most likely to make the public uneasy–children, the retarded, the provably innocent, defendants whose lawyers are drunk or asleep in court. Then shift the focus to defendants less likely to rouse sympathy: serial killers, sexual sadists, “the worst of the worst.” At the same time, the Justice Department continues to use federal capital charges to introduce execution in non-death penalty states.

Roper v. Simmons is a much-deserved vindication for those lawyers who since 1989 have watched, sickened, as their teenage clients were executed. The ruling leaves an end to the American death penalty more clearly in sight. But as the goal draws closer, death penalty abolitionists must be prepared for a debate newly stripped to emotional essentials: the value of vengeance as social policy. We are still far from the moment when a majority of Supreme Court Justices, echoing their late colleague Harry Blackmun, say they will no longer “tinker with the machinery of death” and rule the death penalty, in any form, unconstitutional.