Opinion of the Court
and shared only $50 with someone affiliated with ISIS; the complaint simply does not say, nor does it give any other reason to view Google’s revenue sharing as substantial assistance. Without more, plaintiffs thus have not plausibly alleged that Google knowingly provided substantial assistance to the Reina attack, let alone (as their theory of liability requires) every single terrorist act committed by ISIS.
V
By their very nature, the concepts of aiding and abetting and substantial assistance do not lend themselves to crisp, bright-line distinctions. However, both the common law and Halberstam provide some clear guideposts: The point of aiding and abetting is to impose liability on those who consciously and culpably participated in the tort at issue. The focus must remain on assistance to the tort for which plaintiffs seek to impose liability. When there is a direct nexus between the defendant’s acts and the tort, courts may more easily infer such culpable assistance. But, the more attenuated the nexus, the more courts should demand that plaintiffs show culpable participation through intentional aid that substantially furthered the tort. And, if a plaintiff’s theory would hold a defendant liable for all the torts of an enterprise, then a showing of pervasive and systemic aid is required to ensure that defendants actually aided and abetted each tort of that enterprise.
Here, however, the nexus between defendants and the Reina attack is far removed. As alleged by plaintiffs, defendants designed virtual platforms and knowingly failed to do “enough” to remove ISIS-affiliated users and ISIS-related content—out of hundreds of millions of users worldwide and an immense ocean of content—from their platforms. Yet, plaintiffs have failed to allege that defendants intentionally provided any substantial aid to the Reina attack or otherwise consciously participated in the Reina at-
