Recently, in Twitter, Inc. v. Taamneh (May 18, 2023), the U.S. Supreme Court cited Restatement of the Law Second, Torts, and Restatement of the Law Third, Torts: Intentional Torts to Persons, in holding that the victims of a terrorist attack failed to state a claim under § 2333(d)(2) of the Antiterrorism Act that certain social-media companies aided and abetted the terrorists in committing the attack.

This case arose from a 2017 terrorist attack on the Reina nightclub in Turkey that was carried out on behalf of the Islamic State of Iraq and Syria (ISIS). Family members of a victim killed in the attack brought a claim under 18 U.S.C. § 2333(d)(2) against three social-media companies—Facebook, Inc., Twitter, Inc., and Google, Inc. (owner of YouTube)—alleging that the defendants were liable for aiding and abetting ISIS, because they knowingly allowed ISIS to use their platforms to recruit terrorists, spread propaganda, and raise funds for terrorism. Under § 2333(d)(2), U.S. nationals who have been injured “by reason of an act of international terrorism” could sue for damages “any person who aids and abets, by knowingly providing substantial assistance, or who conspires with the person who committed such an act of international terrorism.” The plaintiffs alleged that ISIS benefited from the defendants’ “recommendation” algorithms, which automatically match advertisements and content with a user “based on a wide range of information about the user, the advertisement, and the content being viewed,” and that, while the defendants were aware that ISIS used their platforms, they failed to remove a substantial number of ISIS-related accounts, posts, and videos, and profited from advertisements on ISIS’s content.

The U.S. District Court for the Northern District of California dismissed the plaintiffs’ complaint for failure to state a claim. The U.S. Court of Appeals for the Ninth Circuit reversed, finding that the plaintiffs plausibly alleged that the defendants aided and abetted ISIS within the meaning of § 2333(d)(2).

The U.S. Supreme Court reversed the Ninth Circuit’s decision, holding that the defendants did not aid and abet by knowingly providing substantial assistance such that they could be liable for the Reina terrorist attack. Pointing out that the statute did not define the terms in the phrase “aids and abets, by knowingly providing substantial assistance,” the Court looked to the common law of aiding and abetting. The Court cited Halberstam v. Welch, 705 F.2d 472 (D.C. Cir. 1983), which, in enacting the statute, Congress referred to as “the proper legal framework” for “civil aiding and abetting and conspiracy liability,” in observing that Halberstam’s framework drew on “a series of state and federal cases, the Restatement (Second) of Torts, and prominent treatises that discussed secondary liability in tort.” The Court reasoned that, under the Halberstam framework and the common law it was based on, “aids and abets” in § 2333(d)(2) “refers to a conscious, voluntary, and culpable participation in another’s wrongdoing.”

Associate Justice Clarence Thomas, writing for a unanimous Court, explained that our legal system seeks to impose liability for aiding and abetting on those with “[s]ome level of blameworthiness,” and cited Restatement of the Law Second, Torts § 876, Illustration 9, in noting that, if liability were expanded too far, “those who merely deliver mail or transmit emails could be liable for the tortious messages contained therein.” The Court rejected the plaintiffs’ argument that the defendants could be liable if they aided and abetted ISIS generally, and explained, citing Restatement of the Law Second, Torts § 876(b) and Comment d thereto, that “a defendant must have aided and abetted (by knowingly providing substantial assistance) another person in the commission of the actionable wrong—here, an act of international terrorism.” The Court also determined that the defendants, who posited that they were liable only if they directly aided and abetted the attack, “overstate[d] the nexus that §2333(d)(2) requires between the alleged assistance and the wrongful act,” because “aiding and abetting does not require the defendant to have known ‘all particulars of the primary actor’s plan,’” according to Restatement of the Law Third, Torts: Intentional Torts to Persons § 10, Comment c (T.D. No. 3, 2018) and Restatement of the Law Second, Torts § 876, Illustration 10. The Court noted that, as was the case in Halberstam, a secondary defendant who aided and abetted a tort could be liable for torts that were a foreseeable risk of the intended tort, and the “secondary defendant’s role in an illicit enterprise can be so systemic that the secondary defendant is aiding and abetting every wrongful act committed by that enterprise.” Citing § 876, Comment a, the Court clarified that conspiracy liability “typically holds co-conspirators liable for all reasonably foreseeable acts taken to further the conspiracy,” but “aiding and abetting lacks the requisite agreement that justifies such extensive conspiracy liability.”

The Court concluded that, “[g]iven the lack of nexus between that assistance and the Reina attack, the lack of any defendant intending to assist ISIS, and the lack of any sort of affirmative and culpable misconduct that would aid ISIS, plaintiffs’ claims fall far short of plausibly alleging that defendants aided and abetted the Reina attack.”

Find the full opinion here.