Response: International law supplies the conduct rules and domestic law governs enforcement

The following response in our symposium on Kiobel v. Royal Dutch Petroleum comes from Oona A. Hathaway, Gerard C. and Bernice Latrobe Smith Professor of International Law at Yale Law School. Oona is the director of the Yale Law School Center for Global Legal Challenges, which filed an amicus brief and a supplemental amicus brief in this case. Oona served as a law clerk for Justice Sandra Day O’Connor.  [Lyle published an introduction to the issues in the case at the start of the symposium.]

In his post, Julian Ku argues that “defenders of the ATS” have shifted ground in Kiobel – using the ATS to enforce international law norms but then retreating to U.S. law for principles of corporate liability, in the process turning the ATS into “just another domestic tort mechanism.”  In fact, since Filartiga it has been clear that under the ATS, international law provides the substantive conduct rules and domestic law determines the means of enforcement of those rules.

The reason for this can be found in the text of the ATS itself.  The ATS provides jurisdiction in the U.S. federal courts for a “civil action” filed by an “alien,” “for a tort only, committed in violation of the law of nations.”   The ATS is a jurisdiction-granting statute.  It does not create new substantive law.  Rather, it expressly relies on “the law of nations” to supply the substantive conduct norms.   But it is domestic law that determines the remedy – in this case civil tort liability.  As the first brief of the United States in Kiobel emphasized, “international law . . . establishes the substantive standards of conduct and generally leaves the means of enforcing those substantive standards to each state.”

The ATS directs the courts to look to international law to determine whether a conduct norm has been violated – whether, in other words, a defendant has engaged in conduct that is prohibited by the “law of nations.”   The first brief filed by the Yale Law School Center for Global Legal Challenges’ therefore examined whether corporations are capable of violating the international law norms often at issue in ATS cases.  We conducted a norm-by-norm analysis of seven major prohibitory norms of international law: genocide, crimes against humanity, torture, extrajudicial killing, war crimes, slavery, and piracy. We examined the contours of these prohibitions, concluding that they are sufficiently specific, universal, and obligatory to meet the requirements set out in Sosa, and then showing that they can apply to corporations as a matter of international law.

But while international law supplies the scope of the conduct rule, it is domestic law that determines the means of enforcement.  As my last post explained, many countries have domestic statutes that provide for both criminal and civil penalties for violations of international law.  When a case is filed against a defendant in one of these countries, it is domestic law that supplies the means of enforcement – whether, for example, the particular actor can be subject to criminal or civil sanctions and what the content of those sanctions might be.

Similarly, in the United States, it is domestic law – the ATS and generally applicable domestic law tort principles – that determines the available sanctions when a conduct norm of international law is violated.  Thus in Filartiga, international law established the conduct norm (as the court put it, “an act of torture committed by a state official against one held in detention violates established norms of the international law of human rights, and hence the law of nations”), and domestic law established the penalty for violating that norm (tort liability).

To return for a moment to the extraterritoriality question that is before the Court on reargument, this understanding of the relationship between domestic and international law in ATS cases helps to explain why the case does not involve extraterritorial application of U.S. law.   The ATS is a jurisdiction-granting statute that does not create new substantive law. In enforcing specific, universal, and obligatory norms of international law through the ATS, U.S. courts are not giving U.S. law extraterritorial reach. They are instead enforcing international law. Nothing in international law prohibits such enforcement; quite the contrary. As we argue in our second brief, each nation-state has broad authority to exercise extraterritorial criminal and civil jurisdiction to enforce international law. This authority is inherent in state sovereignty and is subject only to specific and affirmative international law limitations that are not at issue in Kiobel.