Facts of the Case

Provided by Oyez

This case arises from the same set of facts as Gonzalez v. Google.


Nohemi Gonzalez, a U.S. citizen, was killed by a terrorist attack in Paris, France, in 2015—one of several terrorist attacks that same day. The day afterwards, the foreign terrorist organization ISIS claimed responsibility by issuing a written statement and releasing a YouTube video. Gonzalez’s father filed an action against Google, Twitter, and Facebook, claiming, among other things, all three platforms were liable for aiding and abetting international terrorism by failing to take meaningful or aggressive action to prevent terrorists from using its services, even though they did not play an active role in the specific act of international terrorism that actually injured Gonzalez.


The district court dismissed the claims based on aiding-and-abetting liability under the Anti-Terrorism Act, and the U.S. Court of Appeals for the Ninth Circuit reversed.


  1. Does an internet platform “knowingly” provide substantial assistance under 18 U.S.C. § 2333 merely because it allegedly could have taken more “meaningful” or “aggressive” action to prevent such use?

  2. May an internet platform whose services were not used in connection with the specific “act of international terrorism” that injured the plaintiff still be liable for aiding and abetting under Section 2333?


  1. Twitter did not “knowingly” provide substantial assistance under 18 U.S.C. § 2333, and thus cannot be said to have aided and abetted ISIS in its terrorist attack on a nightclub in Istanbul, Turkey. Justice Clarence Thomas authored the unanimous opinion of the Court.

    Section 2333 establishes liability for anyone “who aids and abets, by knowingly providing substantial assistance, or who conspires with the person who committed such an act of international terrorism.” To “aid and abet” requires three elements: (1) the party whom the defendant aids must perform a wrongful act that causes an injury, (2) the defendant must be generally aware of his role as part of an illegal activity at the time he provides assistance, and (3) the defendant must knowingly and substantially assist the principal violation.”

    The plaintiffs (respondents) in this case satisfied the first two elements by alleging both that ISIS committed a wrong and that the defendants knew they were playing some sort of role in ISIS’s enterprise. They failed to show, however, that the defendants gave such knowing and substantial assistance to ISIS that they culpably participated in the Reina attack. 

    Courts use six flexible factors to assess the third element, whether a defendant knowingly and substantially assisted the principal violation: (1) “the nature of the act assisted,” (2) the “amount of assistance” provided, (3) whether the defendant was “present at the time” of the principal tort, (4) the defendant’s “relation to the tortious actor,” (5) the “defendant’s state of mind,” and (6) the “duration of the assistance” given.

    Applying these factors, the Court found that the plaintiffs failed to allege that Twitter did more than transmit information by billions of people—most of whom use the platform for interactions that once took place via mail, on the phone, or in public areas. Without more, their claim that Twitter aided and abetted ISIS in its terrorist attack on a nightclub in Istanbul must fail.

    Justice Ketanji Brown Jackson authored a concurring opinion to point out the narrowness of the decision due to the stage of litigation (the motion to dismiss stage).