Throwback Thursday: Sosa v. Alvarez-Machain

On June 29, 2004, two decades ago, the Supreme Court decided Sosa v. Alvarez-Machain, recognizing an implied cause of action under the Alien Tort Statute (ATS) for violations of human rights norms that are generally accepted and specifically defined. In this post, I look back at Sosa and discuss what has happened in ATS litigation during the past twenty years.

A Kidnapping in Mexico

In 1990, the U.S. Drug Enforcement Administration (DEA) hired a group of Mexican nationals to kidnap Dr. Humberto Alvarez-Machain from Mexico and bring him to the United States for trial. Alvarez allegedly participated in the 1985 torture and murder of a DEA agent. Alvarez argued that his abduction violated the U.S. extradition treaty with Mexico, but the Supreme Court held that these circumstances did not affect the jurisdiction of U.S. courts to try him.

At the close of the prosecution’s case, the district court granted Alvarez’s motion for a judgment of acquittal. After returning to Mexico, he sued the United States under the Federal Tort Claims Act (FTCA) and his kidnappers—including Sosa, a Mexican national—under the ATS.

The Alien Tort Statute

The ATS was part of the Judiciary Act of 1789, which established the federal courts. As currently codified, it provides: “The 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.” In 1980, the Second Circuit held, in Filartiga v. Pena-Irala, that non-U.S. citizen plaintiffs may sue under this provision for torture committed abroad. The plaintiffs in Filartiga were aliens, torture is a tort, and torture under color of state authority is a violation of customary international law, which is part of the modern “law of nations.”

Four years later, in Tel-Oren v. Libyan Arab Republic (1984), the D.C. Circuit held that terrorism victims could not use the ATS to sue the Palestine Liberation Organization. The three judges could not agree on a single rationale, however. Judge Robert Bork reasoned that the ATS was purely jurisdictional and did not create a cause of action, whereas Judge Harry Edwards thought that the ATS did create a cause of action but did not reach terrorism claims. (Judge Roger Robb thought the political question doctrine barred these claims.) Congress responded by passing the Torture Victim Protection Act (TVPA) in 1992, which grants an express cause of action for torture and extrajudicial killing. The TVPA’s legislative history reflects Congress’s intent that the ATS should remain intact for other violations of customary international law.

Other circuits endorsed Judge Edwards’s position that the ATS provides both jurisdiction and a cause of action. Meanwhile, starting in the mid-1990s, plaintiffs began suing U.S. and foreign corporations under the ATS. Though all this, the Supreme Court remained silent, declining to grant review of an ATS case until Sosa.

The Supreme Court’s Decision

The question before the Court in Sosa was whether an express cause of action was required for suits under the ATS. (With respect to Alverez’s claim against the United States, the Court held that the FTCA’s exception for claims “arising in a foreign country” barred the claim.)

Alvarez argued that an express cause of action was not required because the ATS implicitly created a cause of action in addition to conferring jurisdiction. Sosa, supported by the U.S. government, argued that an express cause of action was required. Writing for the majority, Justice Souter rejected both positions. He agreed instead with the argument of amici professors of federal jurisdiction and legal history that the first Congress expected torts in violation of the law of nations to be cognizable at common law without further congressional action. (Disclosure: I wrote this amicus brief.)

Citing Blackstone’s Commentaries, Justice Souter noted that there were violations of the law of nations in 1789 that were cognizable at common law, including violations of safe conducts, infringement of the rights of ambassadors, and piracy. Souter also detailed the Framers’ concern with observing the law of nations before ratification of the Constitution and passage of the First Judiciary Act. “The jurisdictional grant is best read,” he concluded, “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.”

Turning to claims under the “present-day law of nations,” Justice Souter explained that “[a] series of reasons argue for judicial caution.” First, the understanding of common law had changed since 1789 from something that judges find to something that they make. Second, Erie Railroad v. Tompkins (1938) limited the federal courts’ authority to create federal common law. Third, the modern Supreme Court had repeatedly said that the decision to create a cause of action is, in most cases, best left to Congress. Fourth, “the potential implications for the foreign relations of the United States of recognizing such causes should make courts particularly wary of impinging on the discretion of the Legislative and Executive Branches in managing foreign affairs.” Fifth and finally, he wrote, “[w]e have no congressional mandate to seek out and define new and debatable violations of the law of nations.”

Justice Souter therefore concluded “that federal courts should not recognize private claims under federal common law for violations of any international law norm with less definite content and acceptance among civilized nations than the historical paradigms familiar when § 1350 was enacted”—that is, violations of safe conducts, infringement of the rights of ambassadors, and piracy. He described this standard as “generally consistent” with Filartiga and other lower court decisions.

Alvarez’s claim of arbitrary detention, however, failed to meet this standard. Justice Souter rejected Alvarez’s reliance on the Universal Declaration of Human Rights because it is non-binding and his reliance on the International Covenant on Civil and Political Rights because it is non-self-executing. He also noted that the Restatement (Third) of Foreign Relations Law’s list of human rights norms under customary international law referred to prolonged arbitrary detention. “It is enough to hold,” Souter concluded, “that a single illegal detention of less than a day, followed by the transfer of custody to lawful authorities and a prompt arraignment, violates no norm of customary international law so well defined as to support the creation of a federal remedy.”

Justice Scalia (joined by Chief Justice Rehnquist and Justice Thomas) concurred in the result but would not have recognized an implied cause of action under the ATS for any human rights norms. He noted that in 1789 the law of nations was considered part of the general common law. Erie, however, put an end to this regime of general common law. “Post-Erie federal common lawmaking,” he continued, “is so far removed from that general-common-law adjudication which applied the ‘law of nations’ that it would be anachronistic to find authorization to do the former in a statutory grant of jurisdiction that was thought to enable the latter.”

Twenty years later, Justice Souter’s majority opinion still strikes me as a good faith effort to translate the original understanding of the ATS and the law of nations into modern terms. Certainly, the rise of positivism during the nineteen century changed understandings of common law and international law. And the international law of human rights as we know it today did not exist in 1789. But the Framers expected international law to change, and the First Congress did not limit the ATS by specifying only a few law of nations violations. Justice Scalia’s concurrence, ironically, seems fundamentally anti-originalist, allowing the judicial revolution wrought by Erie to effectively extinguish a provision of the First Judiciary Act. As Souter put it in response to Scalia, “[w]e think it would be unreasonable to assume that the First Congress would have expected federal courts to lose all capacity to recognize enforceable international norms simply because the common law might lose some metaphysical cachet on the road to modern realism.”

Still, the ATS lost something in translation. By founding the ATS cause of action on federal common law, Sosa gave the Supreme Court the authority to shape it. Sosa limited the cause of action to human rights norms that are generally accepted and specifically defined. Over the following two decades, the Supreme Court would whittle the cause of action down still further.

After Sosa

The Supreme Court has heard three more ATS cases since Sosa. In each, the Court initially granted cert to decide if corporations can be sued under the ATS. But again, and again, the Court avoided that question, disposing of each case by narrowing the ATS cause of action in a different way.

In Kiobel v. Royal Dutch Petroleum Co. (2013), the Court applied the presumption against extraterritoriality to the ATS cause of action, holding that the cause of action did not reach the conduct of a foreign corporation abroad. The Court held that ATS claims must “touch and concern the territory of the United States … with sufficient force to displace the presumption against extraterritorial application,” without specifying what this meant.

In Jesner v. Arab Bank, PLC (2018), the Court held that the ATS cause of action does not apply to foreign corporations. Justice Kennedy, joined by Chief Justice Roberts and Justice Thomas would have gone further and barred ATS suits against all corporations, but Justices Alito and Gorsuch demurred. On the other hand, Alito and Gorsuch suggested that it was a mistake for Sosa to recognize a cause of action for any modern human rights claims at all.

Finally, in Nestlé USA, Inc. v. Doe (2021), the Court again applied the presumption against extraterritoriality, abandoning Kiobel’s “touch and concern” test and holding that the ATS cause of action requires substantial conduct in the United States. This meant that claims against U.S. chocolate companies for aiding and abetting child slavery in Côte d’Ivoire had to be dismissed. The number of Justices who would limit the ATS cause of action to violations of the law of nations that existed in 1789 swelled to four with the addition of Justices Thomas and Kavanaugh. On the other hand, the position that the ATS applies to U.S. corporations won the support of five justices—Alito, Gorsuch, Sotomayor, Breyer, and Kagan—though in three different opinions.


For the moment at least, Sosa’s implied cause of action lives on. But it does not reach foreign corporations (Jesner) and requires substantial conduct in the United States (Nestlé), a holding that may doom traditional Filartiga-type ATS suits against individuals.

Some ATS claims still fit within the limits the Supreme Court has imposed. Last year, a Boston jury awarded $15 million against a Haitian defendant under the ATS. Also, the Ninth Circuit allowed claims against Cisco Systems for aiding and abetting torture in China to proceed, based on Cisco’s conduct in California designing and maintaining a surveillance system.

As the ATS cause of action has narrowed, human rights victims have increasingly turned to foreign courts. And in U.S. litigation they have sought to rely on express cause of actions such as the TVPA and the Trafficking Victims Protection Reauthorization Act (TVPRA), or on foreign law as in the recent verdict against Chiquita. Sosa was a landmark case in U.S. human rights litigation, but two decades on only a narrow cause of action remains.