THE SUPREME COURT ended its term with an important, if somewhat indecisive, ruling on a 1789 law that has become an unlikely lightning rod for political controversy. The battle over whether the Alien Tort Statute authorizes foreigners to sue other foreigners in U.S. courts over human rights abuses that occurred abroad has become strangely vicious, pitting human rights groups, law professors and others against the Bush administration. The groups accuse the administration, which argued for a narrow understanding of the statute, of eviscerating a critical tool of accountability for gross abuses of human rights. But, as all of the court's justices recognized, the administration is right to worry about the litigation that has proliferated in the lower courts under this law in recent decades. Having recognized the danger, however, the court did not end litigation under the statute but instead sought to rein it in. Whether it succeeded isn't yet known.

Until 1980, the Alien Tort Statute lay dormant in the federal code. Nobody knows exactly why it was passed, but it probably was intended to give the federal courts jurisdiction over piracy suits and litigation stemming from attacks on ambassadors. Nearly two centuries after its passage, however, lower federal courts discovered in its seemingly broad language the authority to hear claims concerning human rights violations wherever they happen. You don't have to be indifferent to human rights abuses to have misgivings about this reading, because it creates troubling problems for democratic government and permits the courts to interfere excessively in the conduct of foreign policy. The result has been a flood of litigation -- including suits as varied as Bosnian women suing former Bosnian Serb leader Radovan Karadzic over rape and Korean "comfort women" suing the Japanese -- over conduct that, however horrible, is not obviously the province of America's courts to redress. The law has also formed the basis for litigation against U.S. companies involved with nefarious regimes abroad. And while horrid conduct by an American company ought to be, where proven, grounds for action in American courts, the parameters of such litigation are surely a legislative question, not one for the freewheeling discretion of judges. Yet with the exception of suits over torture, Congress has never authorized this type of action.

The court, in an opinion by Justice David H. Souter, seemed genuinely concerned about all of these problems. Indeed, the justices emphasized that judges should allow suits under the Alien Tort Statute only when international law is as clear about the matters being raised today as it was in the 18th century about piracy and attacks on ambassadors. Moreover, the court rightly restricted the use of nonbinding international legal instruments in assessing what norms of conduct are clearly established as international law. But the court left open the possibility that at least some of these suits can proceed in the absence of further congressional action. So it remains to be seen whether what Justice Souter clearly envisions as a narrow opening will stay narrow as the lower courts chew it over. One has to worry, with Justice Antonin Scalia, about an opinion that "wags a finger at the lower courts for going too far, and then . . . invites them to try again."