The Alien Tort Statute (ATS) was enacted by the Congress in 1789 and then virtually was unused through 1979. In 1980 that changed when the U.S. Court of Appeals for the Second Circuit decided that the ATS permitted a lawsuit for money damages by two Paraguayans against another Paraguayan for the torture and killing of a member of their family. For the next 25 years without guidance from the U.S. Supreme Court the lower federal courts upheld many similar cases under the ATS.
In 2004 the Supreme Court finally entered the discussion.
In Sosa v. Alvarez-Machain, 542 U.S. 692 (2004), the U.S. Supreme Court, 9-0, held that a single illegal detention of less than a day, followed by a transfer of custody to lawful authorities and a prompt arraignment did not violate any treaty or norm of customary international law, and, thus, the plaintiff did not have a valid claim for damages under the ATS.
In reaching this holding, the Court, 9-0, in an opinion by Justice Souter, made the following conclusions regarding the ATS:
- The ATS is a jurisdictional statute and does not create a cause of action (id. at 713-14, 729).
- Torts in violation of the law of nations were recognized as being within the common law in 1789, when the ATS was adopted (id. at 714-15, 729).
- Although it is difficult to be certain about congressional intent in adopting the ATS in 1789, Congress did not intend the ATS to be a dead letter until a future Congress or state legislature adopted a statute creating causes of action for torts against the law of nations and instead intended the ATS to be a jurisdictional basis for a “relatively modest set” of such causes of action (id. at 716-24).
The opinion for the Court, 6 to 3, went on to hold that customary international law was part of federal common law, that such international law constituted the customs and usages of civilized nations, as evidenced by the works of well qualified jurists and commentators, and that such international law to give rise to a cause of action for damages under the ATS must have the definite content and acceptance among civilized nations equivalent to the late 18th century’s ban on piracy, infringements on the rights of ambassadors and violation of safe conducts. (Id. at 724-25, 731-32.)
The Court also noted, 6-3, these reasons for “judicial caution” in creating or recognizing such claims in the common law: (1) the concept of common law had radically changed from 1789 to one acknowledging that such law is created or made; (2) common law (since Eire R. Co. v. Tompkins in 1938) is now generally a matter of state law, leaving federal common law to “havens of specialty;” (3) the Supreme Court recently and repeatedly has said that creation of private causes of action generally is better left to legislative judgment; (4) creation of common law causes of action for torts against the law of nations can affect foreign relations which is the responsibility of other branches of government; and (5) Congress has not specifically authorized or encouraged the courts to create such causes of action (id. at 725-30).
In this regard, the opinion, 6-3, said that the lower federal courts since 1980 generally had taken this approach to recognizing such causes of action. It cited the Second Circuit’s opinion in Filartigav. Pena-Irala, 630 F.2d 876 (2d Cir. 1980), that the torturer was like the pirate and slave trader (542 U.S. at 732). The Court also suggested that what was sufficiently definite to be recognized as such a tort as a matter of common law could change over time, citing conflicting lower court opinions, separated by 11 years, on the issue of whether a private actor like a corporation or individual could be liable for such a tort (id. at 732, n.20). In addition, the Court suggested that exhaustion of domestic remedies and case-specific deference to the political branches could be additional limitations on creation or recognition of such torts. (Id. at 733, n.21).
In resolving the specific issue before them, the Court also evaluated the relevance of certain international human rights instruments. The Universal Declaration of Human Rights, the Court said, “does not of its own force impose obligations as a matter of international law” (id. at 734-35). The International Covenant on Civil and Political Rights, on the other hand, did impose obligations on the United States because of its ratification of same, but that ratification was “on the express understanding that it was not self-executing and so did not itself create obligations enforceable in the federal courts” (id. at 735). Indeed, the more general use of such understandings or declarations that certain treaties were not self-executing was recognized by the Court earlier in its opinion (id. at 728).
 See Post: The U.S. Alien Tort Statute, 1789-1979 (Oct. 21, 2011); Post: U.S. Court of Appeals’ 1980 Decision Validates Use of Alien Tort Statute To Hold Foreign Human Rights Violators Accountable (Oct. 23, 2011); Post: The U.S. Alien Tort Statute, 1980-2004 (Oct. 25, 2011).
 Sosa v. Alvarez-Machain, 542 U.S. 692 (2004). The Court also held, 9-0, that the United States Government was immune from liability on the plaintiff’s claim under the Federal Tort Claims Act (id. at 699-712). Justice Ginsburg, concurring, reached the same result on different grounds (id. at 751-60).
 Justice Scalia, joined by Chief Justice Rehnquist and Justice Thomas, dissented on the issue of the federal courts’ ability to recognize or create new causes of action for such torts as a matter of federal common law (id. at 738-51.)
 See: Post: U.S. Court of Appeals’ 1980 Decision Validates Use of Alien Tort Statute To Hold Foreign Human Rights Violators Accountable (Oct. 23, 2011). The concurring opinion of Justice Breyer in Sosa suggested that torture, genocide, crimes against humanity and war crimes constituted matters that were appropriate for damages claims under international law as incorporated into federal common law. (Id. at 760-63.) Justice Breyer also suggested that recognition of such causes of action as a matter of federal common law was consistent with notions of international comity and that the concept of universal jurisdiction for criminal prosecutions was the way to take into account this comity consideration (id.).
 The Court did not consider any treaties that were not ratified by the U.S., but the opinion for the Court strongly suggests that they would not be given any weight.