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Page Number: 36

30 

TWITTER, INC. v. TAAMNEH 

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 as-
sistance.  Without more, plaintiffs thus have not plausibly
alleged that Google knowingly provided substantial assis-
tance to the Reina attack, let alone (as their theory of lia-
bility 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 plain-
tiff ’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,  de-
fendants  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 world-
wide  and  an  immense  ocean  of  content—from  their  plat-
forms.  Yet, plaintiffs have failed to allege that defendants
intentionally provided any substantial aid to the Reina at-
tack or otherwise consciously participated in the Reina at-