Opinion of the Court
be taken as inflexible codes; rather, they should be understood in light of the common law and applied as a framework designed to hold defendants liable when they consciously and culpably “participate[d] in” a tortious act in such a way as to help “make it succeed.” Nye & Nissen, 336 U. S., at 619 (internal quotation marks omitted). And the text requires that defendants have aided and abetted the act of international terrorism that injured the plaintiffs—though that requirement does not always demand a strict nexus between the alleged assistance and the terrorist act.
IV
Under the appropriate framework, some aspects of today’s case become immediately clear: First, because they are trying to hold defendants liable for the Reina attack, plaintiffs must plausibly allege that defendants aided and abetted ISIS[1] in carrying out that attack. Next, plaintiffs have satisfied Halberstam’s first two elements by alleging both that ISIS committed a wrong and that defendants knew they were playing some sort of role in ISIS’ enterprise. The key question, therefore, is whether defendants gave such knowing and substantial assistance to ISIS that they culpably participated in the Reina attack. The allegations here fall short of that showing under Halberstam’s framework as properly understood by reference to the common-law principles it applied.
A
To start, recall the basic ways that defendants as a group allegedly helped ISIS. First, ISIS was active on defendants’
- ↑ For purposes of this case, we need not resolve whether defendants must have aided and abetted ISIS, Masharipov, or some subgroup of ISIS operatives in committing the Reina attack. In other words, we need not resolve whether “the person” referred to in §2333(d)(2) encompasses international terrorist syndicates or is somehow otherwise limited; either way, defendants need to have aided and abetted that “person” in carrying out the Reina attack.
