[Editor’s Note: This article is part of a Just Security series on the consolidated cases of Nestlé USA, Inc. v. Doe I and Cargill Inc. v. Doe I, which was argued before the Supreme Court on Dec. 1. The introduction to the series and all other articles can be found here.]

Slavery is among the oldest prohibitions under international law. In Nestlé USA, Inc. v. Doe I, slated for oral argument on Dec. 1st, however, the Supreme Court will consider whether to exempt domestic corporations from liability under the Alien Tort Statute (ATS) for their alleged roles in practices of slavery, child slavery, forced labor, and human trafficking, all prohibited under international law. In our amicus brief filed in support of respondents on behalf of the Yale Law School Center for Global Legal Challenges, we argue that the Supreme Court should not exempt corporations from such liability.

The ATS provides federal district courts with jurisdiction over a “civil action” filed by “an alien,” “for a tort only” that is “committed in violation of the law of nations.” In Sosa v. Alvarez-Machain (2004), the Supreme Court declared that “the door is still ajar” to recognizing a “narrow class of international norms today” as valid claims under the ATS, albeit “subject to vigilant doorkeeping.” The Court set a threshold that any such claims would need to rely on norms recognized as “specific, universal, and obligatory” under international law. In addition, the Court noted in a footnote that the norms must extend to the “perpetrator being sued, if the defendant is a private actor such as a corporation or individual.” While international law determines the scope of applicability of a specific norm, it leaves the enforcement of these obligations to individual States.

Our amicus brief argues that if any international law norms meet the Sosa threshold, they are the norms at issue in Nestlé. The respondents in Nestlé – former child slaves from Mali who were trafficked to work as slave labor on cocoa plantations in the Ivory Coast – allege that the two food giants Nestlé USA and Cargill knowingly aided and abetted these international law violations through technical assistance and financial contributions from their U.S. offices. The facts in Nestlé are particularly disturbing because they involve the exploitation of children. Unfortunately, these plaintiffs are far from alone: An estimated 4 million children are currently subjected to forced labor around the world. Children are also particularly vulnerable to human trafficking, making up around 30 percent of human trafficking victims worldwide. While child labor is more likely to be involved in production for the domestic economy, many children are employed in the supply chains of major international corporations.

The Prohibition on Slavery Meets the Sosa Test

In our brief, we trace the long history of prohibitions on the slave trade and slavery to show that they are among the oldest and most widely accepted international law prohibitions. If a norm of this pedigree does not meet the Sosa test, it is not clear what would.

In the early and mid-nineteenth century, many nations first abolished the slave trade and then the practice of slavery, freeing hundreds of thousands of men, women, and children from bondage. In a detailed historical review of the slave trade, Jenny Martinez writes that by “the early 1840s, more than twenty nations . . . had signed treaties committing to the abolition of the slave trade.” This made the slave trade prohibition one of the most widely accepted international law obligations of its era.

The customary international law prohibition against slavery was codified in the 1926 Slavery Convention, which defines slavery as “the status or condition of a person over whom any or all of the powers attaching to the right of ownership are exercised.” Freedom from slavery is an inviolable right and jus cogens norm of international law. The International Covenant on Civil and Political Rights (ICCPR) of 1966 confirms the non-derogable nature of the right, even “[i]n time of public emergency which threatens the life of the nation” (Article 4(2)).

From its inception, the prohibition on slavery implicated corporate activity, since mercantile and joint stock companies played a leading role in the transatlantic slave trade. Indeed, the Royal African Company, a private mercantile company established in 1660, shipped more enslaved Africans to the Americas than any other organization.

The first international human rights tribunals were created specifically to enforce the slave trade prohibition. These tribunals imposed penalties on private actors and directly against slave ships, the juridical entities carrying out the slave trade – including ships owned by mercantile companies. These early international human rights tribunals seized and condemned over 600 slave trading vessels by the mid-nineteenth century. The seizure and condemnation of slave ships mirrored the enforcement actions States had long undertaken against ships engaged in piracy. The United States, along with several other nations, even declared that anyone participating in the slave trade was guilty of piracy. Thus, enforcing the prohibition against the slave trade has for centuries entailed enforcement against private companies. Martinez aptly notes that companies “clearly believed that the treaties banning the slave trade applied to them; otherwise, an easy way to avoid the ban would have been simply to incorporate.”

The Prohibition on Forced Labor Meets the Sosa Test

The prohibition against forced labor can be traced back to the prohibition against slavery. The Forced Labour Convention of 1930 crystallized the prohibition and defined forced labor as “all work or service which is exacted from any person under the menace of any penalty and for which the said person has not offered himself voluntarily.” The right the be free from forced or compulsory labor is reflected in Article 8 of the ICCPR.

Much like the prohibition on slavery, the prohibition on forced labor has historically extended to corporate conduct. Nearly a century after the slave trade tribunals condemned slave ships owned by joint stock companies, the Nuremberg trials denounced the corporate exploitation of forced labor during World War II. In the trial of corporate officers of the German petrochemical and pharmaceutical company Farben, the Tribunal concluded that the corporation itself had violated international law, although the Tribunal’s jurisdiction was limited to adjudicating the liability of natural persons. The Tribunal explained that “Farben . . . utilized involuntary foreign workers in many of its plants” and that “unless done under such circumstances as to relieve the employer of responsibility” this “constitute[d] a violation of [international law].” Since Nuremberg, several U.S. courts have likewise found that the prohibitions on forced labor extend to corporations, including in Flomo v. Firestone Nat. Rubber Co. (2011), Licea v. Curacao Drydock Co. (2008), and Iwanowa v. Ford Motor Co. (1999).

The Prohibition on Human Trafficking Meets the Sosa Test

The historical roots of the international law prohibition on human trafficking trace back to the prohibition on the slave trade as well. The prohibition on human trafficking is codified in the Palermo Protocol of 2000, which supplements the United Nations (U.N.) Convention against Transnational Organized Crime. The Protocol outlaws the “recruitment . . . of persons, by means of the threat or use of force or other forms of coercion . . . for the purpose of exploitation,” including “forced labor or services [and] slavery or practices similar to slavery.”

Like slavery and forced labor, human trafficking is often carried out by private actors motivated by financial incentives. In recognition of this fact, the U.N. Convention Against Transnational Organized Crimes requires liability for legal persons, including corporations. U.S. law has also recognized that the only way to effectively combat the global phenomenon of human trafficking is to hold corporations accountable for their involvement in these violations. Notably, through the Victims of Trafficking and Violence Protection Reauthorization Act (TVPRA), Congress has recognized both individual and corporate liability. The TVPRA is focused exclusively on U.S. victims, making the ATS an important complement to ensure corporate accountability for human trafficking with foreign victims.

Domestic Corporations are Not the Same as Foreign Corporations

The Nestlé case comes on the heels of the Court’s decision in Jesner v. Arab Bank (2018), in which the Supreme Court rejected foreign corporate liability under the ATS out of a sense that it would constitute undue judicial interference in foreign affairs and could risk American interests abroad. However, recognizing domestic corporate liability under the ATS does not raise the same concerns.

First, domestic corporate liability does not infringe upon a foreign sovereign’s judicial power, which was a contention that the Kingdom of Jordan raised in an amicus brief in Jesner and that other countries had raised in previous ATS cases involving foreign corporations. It is thus not surprising that no foreign sovereign has weighed in on Nestlé. After all, it is the U.S. prerogative to hold its subjects, including its corporations, accountable for their violations of international law.

Second, recognizing domestic corporate liability under the ATS does not carry the risk identified in Jesner of setting a precedent that other countries’ courts may hold U.S. corporations liable, since allowing this suit to proceed would not entail holding foreign corporations responsible. If anything, recognizing domestic corporate liability in this case would potentially reduce the risk of U.S. corporations being forced to defend themselves in foreign courts.

Finally, recognizing domestic corporate liability has the potential to reduce diplomatic strife with other countries, since United States’ failure to hold its subjects accountable for international law violations abroad has the potential to offend other States. In fact, countering the risk of reprisals is precisely one of the reasons behind the ATS’s enactment in the first place. A study of war manifestos issued by States from the mid-1400s through the early-1900s to explain their reasons for going to war shows that 42.5 percent cited violations of the law of nations as a reason for waging war. As David Golove recently explained, the whole point of the ATS was precisely to make relief available to aliens for extraterritorial tortious violations of the law of nations by U.S. citizens—and thus avoid reprisal or worse.

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The international law prohibitions on slavery, forced labor, and human trafficking are among the most longstanding, deeply rooted human rights norms. Our brief shows that these norms are all specific, universal, and obligatory, and their scope of application extends to both State and non-State actors, including corporations. Indeed, corporations have been bound by the norms at issue in Nestlé for centuries. They should not be exempted now.

Image: Workers who come from Burkina Faso carry sacks of cocoa to a truck June 28, 2001 in Petit Tieme, Ivory Coast. Cheap labor–including child workers–from Mali and Burkina Faso contribute to the cocoa industry in Ivory Coast. (Photo by Tyler Hicks/Getty Images)