Customary international law as federal law after Sosa v. Alvarez-Machain.

Position:Proceedings of the 101st Annual Meeting of the American Society of International Law: The Future of International Law - Discussion

The panel was convened at 9:00 a.m., Friday, March 30, by its moderator, Martin Flaherty of Fordham University School of Law, who introduced the panelists: Julian Ku of Hofstra University School of Law; David Moore of the University of Kentucky College of Law; Ralph Steinhardt of George Washington University School of International Affairs; and Beth Stephens of Rutgers University.


By Martin S. Flaherty *

With Sosa v. Alvarez-Machain, (1) the Supreme Court broke nearly twenty-five years of silence concerning modern human rights litigation under what is now commonly known as the Alien Tort Statute (ATS). (2) Justice Souter's majority opinion answered settled several important questions, not least by confirming the ongoing legitimacy of suits under the ATS. Yet as is true of most of the Court's increasingly frequent forays into foreign relations law, Sosa raised as many questions as it settled.


The ATS was enacted by the First Congress in 1789. In slightly modified modern form, it states in its entirety that "The federal district courts shall have original jurisdiction of any civil action by an alien for a tort only, committed in violation of the law of nations or a treaty of the United States." Famously termed by Judge Henry Friendly a "legal Lohengrin," (3) the statute lay more or less unused until the Second Circuit revived it in Filartiga v. Pena-Irala. (4) In this case the family of a "disappeared" person under a dictatorship in Paraguay brought suit against a former Paraguayan colonel who happened to have immigrated to Brooklyn. Writing for the court, Judge Irving Kaufman reasoned that the family had validly alleged that their son had suffered torture, that torture had evolved into a violation of customary international law, and that the suit could go forward.

Filartiga spurred over 20 years of litigation in which various victims of human fights abuses, aided by groups such as the Center for Constitutional Rights, transformed the statute into a uniquely American mechanism for human rights advocacy. ATS defendants would comprise an international rogues' galley, running from unknown torturers to the president of the Republika Srpska, Radovan Karadzic. (5) In recent years, ATS suits have become ever more innovative. Plaintiffs have brought actions against defendants within the United States, such as private companies to whom the United States has franchised out the job of maintaining detention centers for aliens. Still others have filed suit against corporations such as Unocal Corp. for aiding and abetting human rights violations by repressive host regimes like Myanmar. (6)

At just this point opposition to ATS suits began in earnest. Some skepticism had always existed. Judge Robert Bork, for example, wrote a noted opinion arguing that at best the ATS authorized only suits for violations of the law of nations as it existed in 1789. (7) Every Circuit Court to have considered the statute nonetheless had approved the ATS in its modern human rights incarnation. Recent suits against corporations, however, raised the stakes and the resistance. Perhaps not coincidentally, the executive branch under the current administration switched sides. Previously, the United States under the Reagan, (first) Bush, and Clinton White Houses filed amicus briefs in support of ATS claims. The present administration, however, took the position that since the statute by its terms speaks only about the federal courts having jurisdiction, it does not create a cause of action. In other words, the ATS was purely jurisdictional. Without more, the previous quarter century of human rights litigation was unauthorized.


The Supreme Court itself had held aloof from ATS litigation until it granted certiorari in Sosa. The facts could not have been worse from the point of view of the human rights movement. The case involved a doctor, Humberto Alvarez-Machain, who was making his second appearance before the Supreme Court. His case involved the accusation that he had kept alive a U.S. DEA agent in order for that agent to be tortured by drug lords in Mexico. The first time his case came before the Supreme Court was to challenge his abduction by DEA agents for the purpose of bringing him to trial. Then the Court considered whether the Extradition Treaty between the United States and Mexico provided the exclusive means for bringing Mexican suspects to the U.S. for trial, thus effectively prohibiting abduction by U.S. agents for that purpose. Alvarez-Machain lost on that issue, (8) was tried and acquitted nonetheless. Sosa arose when Alvarez-Machain filed suit against U.S. and Mexican officials seeking damages for his abduction under, among other things, the ATS.

The Court upheld human rights litigation under the ATS in a manner that was both clear and qualified. It rejected the claim that the statute was jurisdictional only, reasoning that Congress in the late eighteenth century would have had the expectation that the courts would have looked to the common law and have applied the common law derived from the law of nations to recognize and apply certain causes of action. As Justice Souter put it, "[t]he jurisdictional grant is best read as having been enacted on the understanding that the common law would provide a cause of action for the modest number of international law violations with a potential for personal liability at the time." (9)

There was, however, an apparent catch. The Court further held that any judicial recognition of a cause of action for a modern human rights violation would have to be comparable to those recognized in the late eighteenth century, specifically, piracy, assaults on ambassadors, and violations of safe conduct. In the Court's words: "We think that courts should require any claim based on the present-day law of nations to rest on a norm of international character accepted by the civilized world and defined with a specificity comparable to the features of the 18th-century paradigms we have recognized." (10) Modern violations such as torture, extrajudicial killing, or arbitrary and prolonged detention must in other words satisfy a requirement of: (1) generality, which itself echoes one of the principal bases for deriving customary international law rules; and (2) specificity comparable to the eighteenth-century prohibitions. Under these requirements, most of the last twenty years of ATS litigation would seem to be preserved.

But further prudential language may pose difficulty for more novel suits. Justice Souter went on to explain that a series of background "reasons argue for judicial caution" when considering the kinds of claim that might implement the jurisdiction conferred by the early statute. (11) These reasons drew fairly clearly from scholarship that has expressed skepticism about modern human rights litigation, most notably by Professors Curtis Bradley and Jack Goldsmith. (12) One reason for caution was the general shift from natural law to positivism that occurred from the eighteenth to the twentieth centuries. Second was a reflection of that shift in Erie v. Tompkins, and the shift away from federal courts making national common-law rules. Third, related separation-of-powers concerns counseled that the legislature, rather than the courts, is best suited to establish new causes of action. Fourth, judicial recognition of international law causes of action might have serious consequences for U.S. foreign policy. Fifth and finally, Congress has not authorized modern human rights causes of action beyond the Torture Victim Protection Act. (13)

For his part, Alvarez-Machain may have won the ATS war, but he lost his own battle. He had claimed that his arrest and overnight detention in Mexico violated customary international law. The Court disagreed. Relying mainly on its specificity criterion, the majority concluded that, "a single illegal detention of less than a day, followed by the transfer of custody to lawful authorities and prompt arraignment, violates no norm of customary international law so well defined as to support the creation of a federal remedy." (14) He might well have lost even in the absence of the added requirement for specific definition. Under straightforward international law analysis, a norm prohibiting unauthorized arrest and one-day detention likely does not meet either the requirement of generality nor opinio juris.

Precisely because of the ATS, Sosa does not deal directly with the domestic status of customary international law in the absence of a congressional authorization. But the Court did seemingly nod its approval here as well. It briefly noted its jurisprudence affirming judicial application of international law in appropriate instances, including the derivation of international law principles in a common-law fashion. It further noted that his tradition continued after Erie, as manifested in Banco Nacional de Cuba v. Sabbatino, (15) which "itself did not directly apply international law ... but neither did it question the application of that law in appropriate cases, and it further endorsed the reasoning of a noted commentator [Philip Jessup] who had argued that Erie did not preclude the continued application of international law in federal courts." (16)


Going forward, Sosa presents any number of issues. Two sets stand out. First, what is the future of human rights litigation? The case was a clear victory for international human rights advocacy, yet one with several yellow flags. What exactly will the clear definition rule mean in practice, especially since--unlike the generality requirement it has no clear parallel in customary international law? And what will either requirement mean for the current wave of litigation? In that context, the Court noted other potential limiting doctrines as well. May non-state actors such as corporations be held liable for aiding...

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