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A Fresh Take

Insights on M&A, litigation, and corporate governance in the US.

| 4 minutes read

Supreme Court Resets Aiding and Abetting Liability Threshold in Anti-Terrorism Act Cases

Since 2016, plaintiffs have used increasingly aggressive “aiding and abetting” theories to make Anti-Terrorism Act claims against multinational companies. These claims have spanned multiple sectors: technology and social media, pharmaceuticals, telecommunications, construction, banking and others. There has been some ambiguity about what constitutes “aiding and abetting” terrorism in these cases, with different courts applying different tests. In a much-anticipated case involving social media platforms captioned Twitter v. Taamneh, the US Supreme Court took a big step towards clarifying that standard.

The question in Taamneh was whether social media platforms could be held liable under the Anti-Terrorism Act for allegedly aiding and abetting a terrorist attack that ISIS committed in Turkey. According to the complaint, the defendants aided and abetted the attack because members of ISIS used the social media platforms to spread their campaign, i.e., to post propaganda and recruit members; there was no allegation that ISIS used the platforms to plan or implement the attack itself.

In December, Freshfields submitted an amicus brief in this case on behalf of InterAction and Charity & Security Network, both of which are composed of nonprofits and humanitarian aid organizations. Consistent with the defendants’ position, the brief urged the Court to reject the Ninth Circuit’s expansive reading of aiding-and-abetting liability under the Anti-Terrorism Act because it risked crippling vital humanitarian and development work that non-governmental organizations (NGOs) perform in the world’s most fragile states.

The Supreme Court ruled in favor of the social media companies in a unanimous opinion, holding that the plaintiffs failed to allege that the social media companies aided and abetted the attack. The decision provided helpful guidance on the contours of secondary liability under the ATA.

By way of background, aiding-and-abetting claims under the Anti-Terrorism Act require a plaintiff to demonstrate (i) that there was a wrongful act causing an injury that was performed by the person whom the defendant aided; (ii) that the defendant was generally aware that it was assuming a role in terrorist activities; and (iii) that the defendant knowingly and substantially assisted the principal violation. In Taamneh, where Twitter challenged the Ninth Circuit’s interpretation of the third prong, the Supreme Court clarified the aiding-and-abetting standard in three major respects:

  • First, in parsing the ATA statute, §2333(d)(2), the Court held that the phrase "aids and abets, by knowingly providing substantial assistance," necessitates more than general awareness. When Congress added aiding-and-abetting liability to the ATA in 2016, it explained that an appeals court decision, Halberstam v. Welch, provided the proper legal framework for aiding-and-abetting liability. Accordingly, to date, courts have generally relied on the six-factor test set forth in Halberstam to determine whether a defendant has knowingly and substantially assisted a terrorist. But in Taamneh, the Court clarified that applying Halberstam’s legal framework means applying its “basic thrust,” rather than “rigidly focus[ing]” the cases “facts or its exact phraseology.” Op. 11, 16.
  • Second, and relatedly, the Court held that the basic thrust of Halberstam is that a defendant knowingly provides substantial assistance to an act of international terrorism only if “the defendant consciously and culpably participate[s] in [the] wrongful act so as to make it succeed.” Op. 17. In its survey of U.S. common law defining “culpable conduct,” the Court concluded that a culpable individual must be directly involved in the principal wrongdoing: examples include driving a getaway car or giving verbal encouragement to commit a crime. Mere passive involvement, on the other hand, is insufficient to constitute culpability.
  • Third, a plaintiff must also show that a defendant aided and abetted a particular attack, rather than a “transcendent [terrorist] ‘enterprise’ separate from and floating above all actionable wrongs that constitute it.” Op. 19. In other words, a defendant must participate in a terrorist act in a way that helps “it succeed.” Op. 17. That said, the Court clarified that a defendant can be liable even if it does not know all of the specifics of a particular attack, as long as the attack was a “foreseeable risk” of the defendant’s activities. Op. 20.

Applying all of this to the social media defendants, the Supreme Court ruled that the relationships between those companies and the attack that injured the plaintiffs’ family members were “highly attenuated.” Op. 24. Indeed, these social media platforms allow hundreds of millions, or even billions, of users to upload information on a daily basis, and there was no allegation that the defendants treated ISIS differently from any other user. Because the three platforms could not be shown to have encouraged, solicited, or advised the single alleged ISIS terrorist attack in Turkey in any way, the allegations were insufficient to allege aiding-and-abetting liability. Further illustrating the risks of overextending aiding-and-abetting liability, the Court explained that holding the social media platforms liable for the specific ISIS attack would be akin to holding the defendants liable for having aided and abetted each and every ISIS terrorist act committed anywhere in the world. Therefore, the Court held, a defendant can be held liable for aiding and abetting every terrorist attack perpetrated by a terrorist group only when that defendant is alleged to have  “systemically and pervasively“ assisted that terrorist group, or formed a “near-common enterprise” with that group. Op. 25-26. To rule otherwise would take aiding-and-abetting liability “far beyond its essential culpability moorings.” Op 24.

What does all of this mean for defendants facing aiding-and-abetting claims under the ATA? Ultimately, Taamneh makes it more difficult for plaintiffs to plead ATA aiding-and-abetting claims. For one, plaintiffs must allege that defendants have a culpable state of mind. Under Taamneh, it is not enough for a defendant to be generally aware that it is assuming a role in terrorist activities; instead, the ATA is designed to attribute liability only when a defendant “consciously and culpably” participates in an international terrorist act in a way that helps “it succeed.” Op. 21. And whether a defendant possesses that culpability will now be determined by a more flexible standard, rather than by the rigid six-factor test set forth in Halberstam. Second, a plaintiff must allege that a defendant aided and abetted a particular attack. If a plaintiff ’s theory would hold a defendant liable for all of the attacks of an enterprise, then the plaintiff must allege that the defendant’s aid was so “pervasive and systemic” that it effectively aided and abetted each tort of that enterprise. Op. 30. Highlighting that this is a high bar, the Court observed that this type of systemic role in aiding and abetting “begins to blur with conspiracy liability.” Op. 20.