The very wording of the ATS – “a tort only, committed in violation of the law of nations” – suggests that not only a court’s jurisdiction, but also the norms applicable to a civil liability suit must be considered in the light of international law. This point is controversial in U.S. jurisprudence and doctrine. In determining the applicable law, U.S. courts have three options available to them:

  • International law,
  • The law of the forum court (lex fori), including federal common law, 1 and
  • The law of the place where the damage occurs. 2

International law: jurisprudence selection

Most ATS cases refer to international law to decide which law is applicable to the case.

In Doe v. Unocal, the court ruled 3 that it was preferable to apply international law rather than the law of a particular country 4 in determining Unocal’s liability for violations committed by Burmese forces, due to the nature of the alleged violations (of jus cogens norms). 5 The court’s decision was based on jurisprudence from international criminal tribunals for Rwanda and the former Yugoslavia. 6

References to international law may

  • Be direct, or
  • Be based in federal common law. 7

Opinions are divided on choosing between these two options. In the Unocal case, the court did not address its selection of international law because the applicable norms of international law were similar to those of forum law. 8

Lex fori (federal common law): doctrine selection

Unlike international or foreign law, federal common law offers maximum flexibility in determining the applicable standards of liability and compensation. The application of federal common law does not preclude consideration of international law objectives, provided they are part of the case, and it has the additional advantage of being well-known by the court. In the eyes of federal common law, the application of international law is disadvantaged by its incomplete nature and, more particularly, by its lack of criteria for determining adequate compensation. 9

Law of the place where the damage occurs: an inadequate solution

With several exceptions, 10 jurisprudence indicates that turning to the law of the place where the damage occurs (lex loci damni) is inadequate . 11

The application of foreign law can be problematic, for example, when: –It is not sufficiently protective of victims,

  • It tolerates or even requires the non-observance of international human rights law,
  • It provides certain amnesties,
  • It does not provide for the awarding of damages, or
  • It provides a short statute of limitations.

Another option: Transitory Tort litigation in state courts

State courts can hear “transitory torts,” claims arising outside their territory, if the court has personal jurisdiction over the defendant, by virtue of the defendant’s transitory presence in the United States at the time of the suit. 12 The Supreme Court briefly mentioned the transitory tort doctrine in Kiobel without questioning it. 13

Litigating in state court implies a choice of law analysis. Different states have different choice of law rules. When a human rights case involves conduct outside the forum state’s territory, there are at least three potential sources of applicable law: the domestic law of the place where the conduct occurred (lex loci), the domestic law of the forum state (lex fori), and international law. 14 Many international human rights claims have parallels in state tort law, for example, wrongful death, assault, and battery. However, transitory tort cases involving foreign litigants and foreign events will generally apply the law of the place of injury. 15 Under almost every choice-of-law approach, concerns for international comity and foreign sovereign interests must be built into the analysis.

Possible advantages

  • May avoid heightened federal pleading standards;
  • Avoids the high threshold of definiteness and universality required by Sosa;
  • Forum non conveniens does not have the same importance as in federal courts;
  • Theories of corporate liability are likely to be more expansive and less contested than in ATS litigation. 16

Possible disadvantages

  • Procedural rules are different in each state, whereas federal rules are the same all over the U.S.;
  • each state has its own standards for personal jurisdiction;
  • each state has different pleading requirements;
  • Statutes of limitations will likely be shorter than in federal court;
  • State court judges are elected and therefore may be more vulnerable to pressure from corporations.


Cases against Union Carbide (Bhopal) and Occidental Petroleum , which involve environmental contamination in foreign countries, are proceeding under ordinary claims for “toxic torts” (negligence, trespass, nuisance, for example) under the “transitory tort” doctrine. 17

In Doe v. Unocal Corp .(see above), the plaintiffs refiled their pendent state claims in the state trial court after the ATS claims were dismissed in the federal trial court. While an appeal of the dismissal of the ATS claims was pending, plaintiffs completed discovery in state court and prepared for trial. The case settled several months before the state court trial was scheduled to begin and shortly before an oral argument before the Ninth Circuit. The Unocal plaintiffs were able to assert all of their ATS claims as state common law tort claims in the state court case. 18