In their briefs and oral arguments before the Supreme Court earlier this month, counsel in Jesner v. Arab Bank met some astronomical expectations. But questioning from Justices Kagan and Sotomayor, drawing on the amicus brief of comparative law scholars, suggests that one argument may have particular salience in the resolution of Jesner and in future Alien Tort Statute (ATS) litigation as well. That brief, which – full disclosure – I helped to draft, argues that Jesner should be resolved by reference to “the general principles of law accepted by civilized nations.”

If there is such a thing as hornbook law anymore, the role of general principles as a source of international law qualifies. Article 38(1)(c) of the International Court of Justice Statute couldn’t be clearer, and the U.S. Supreme Court’s use of general principles as a source of international law, though rare, is uniform and principled. There can be no argument that general principles drop like rain out of Holmes’ “brooding omnipresence in the sky” so as to trigger the Sosa v. AlavarezMachain court’s concern with natural law constructs or the unaccountable federal common law that the revisionists railed against in their heyday. To the contrary, general principles traditionally reside in the common doctrinal elements in legal systems worldwide, and are elevated as appropriate to the international plane. Only a systematic comparative study can illuminate these general principles, but, once that demanding evidentiary standard is met, they can qualify as a source of international law for purposes of finding a Sosa-qualified norm. That is, a specific, universal, and obligatory norm, like “the eighteenth-century paradigms” from which the federal courts may infer a cause of action under the ATS.

In the U.S Second Circuit Court of Appeals’ 2010 ruling on Kiobel v. Royal Dutch Petroleum, (known as Kiobel I), the court whiffed badly on this particular pitch, and it perpetuated the mistake by incorporation in Jesner. Judge Cabranes erroneously treated general principles as depending on proof of opinio juris; indeed, while acknowledging that corporate liability has been accepted by foreign legal systems, he dismissed this evidence because, “although interesting as a matter of comparative law,” it “does not demonstrate that corporate liability has attained the status of customary international law,” because it was not universally accepted as obligatory to the extent required for opinio juris (see footnote 43 here). That now-repeated error is rookie-level stuff: general principles are a distinct source of international law, proved not through the universal practice of states among one another combined with opinio juris, as customary international law is. General principles are proven by seeking the common doctrines among domestic legal systems.

That empirical standard is fully satisfied with respect to the civil liability of corporations for harm they cause to others. There is no country on the planet that immunizes corporations from civil liability for their torts or delicts. Nine years ago, the International Commission of Jurists’ Expert Panel on Corporate Complicity in International Crimes (of which I was a member) commissioned a variety of comparative law studies and concluded that in “every jurisdiction, despite differences in terminology and approach, [a corporate actor] can be held liable under the law of civil remedies if through negligent or intentional conduct it causes harm to someone else.” And elsewhere: “Across all jurisdictions, civil liability can arise for both companies as legal entities and for company officials, as natural persons.”

The analytical consequences of this uniformity regarding corporate civil liability seem to me profound. First, it establishes the utter irrelevance of Arab Bank’s truism that corporations are generally immune from the criminal jurisdiction of international criminal tribunals. There is no “general principle” establishing corporate criminality, and the jurisdiction of the international criminal tribunals has not been extended to juridical entities, but all of that taken together says precisely nothing about the civil liability issue in Jesner.

Even more significant, general principles offer authoritative guidance for finding Sosa-qualified norms, despite pointed disagreement about what exactly Sosa requires or what a putative norm must do or address. In the thirteen years since Sosa was decided, litigators and judges have suggested that what matters is whether international law prohibits the underlying conduct: genocide, yes; violations of First Amendment-like standards of free speech, no. At oral argument in Jesner, Justices Kagan, Sotomayor, and Ginsburg seemed to embrace this approach, stressing that international law identifies the wrong, and domestic legal systems provide a variety of remedies when that norm is violated. Applying that rubric, anyone (or anything) that engages in human trafficking or the financing of terrorism will have violated a Sosa-qualified norm.

Another possibility is that the Sosa-qualified norm must identify who or what can be responsible for a violation. This goes to the distinction between wrongs that require state action and those that do not. Sosa’s footnote 20 requires us to distinguish between torture under the Convention Against Torture, which does require state action, and genocide, which does not. That leaves open the question of when an individual – natural or juristic – might be so enmeshed with public authority as to bear state-like responsibility, an issue that brings the proper aiding and abetting standard front and center.

But Respondents (and Judge Cabranes) insist on a different approach to Sosa-qualified norms, requiring international consensus on the remedy, and it is here that general principles are in my mind decisive. Every nation imposes the obligation on corporations to remedy their torts (or in the civil law context, delicts) and provides the remedy of civil damages. That being true, the burden of persuasion ultimately shifts to those who would immunize the subset of corporate torts involving the most egregious conduct.