Document ID: ./input/supremecourt_opinions/opinions/22pdf/21-1496_d18f.pdf
Page Number: 34.0

28 

TWITTER, INC. v. TAAMNEH 

Opinion of the Court 

id.,  at  908.    But,  as  discussed  above,  “the  knowledge  and 
substantial  assistance”  components  “should  be  considered 
relative to one another” as part of a single inquiry designed 
to  capture  conscious  and  culpable  conduct.  Camp,  948 
F. 2d,  at  459  (internal  quotation  marks  omitted).    The 
“knowing” part of that inquiry is therefore designed to cap-
ture the defendants’ state of mind with respect to their ac-
tions and the tortious conduct (even if not always the par-
ticular terrorist act), not the same general awareness that 
defines Halberstam’s second element. 

Finally,  when  applying  Halberstam’s  six  substantiality 
factors, the Ninth Circuit appears to have regarded the fac-
tors  as  a  sequence  of  disparate,  unrelated  considerations
without a common conceptual core.  See 2 F. 4th, at 909– 
910.  That is incorrect.  The point of those factors is to help
courts capture the essence of aiding and abetting: partici-
pation in another’s wrongdoing that is both significant and 
culpable enough to justify attributing the principal wrong-
doing  to  the  aider  and  abettor.  The  Ninth  Circuit  thus 
erred in focusing (as it did) primarily on the value of defend-
ants’  platforms  to  ISIS,  rather  than  whether  defendants 
culpably associated themselves with ISIS’ actions.  For ex-
ample,  when  applying  the  second  factor  (the  amount  and 
kind of assistance), the Ninth Circuit should have consid-
ered  that  defendants’  platforms  and  content-sorting  algo-
rithms were generally available to the internet-using pub-
lic.  That  focus  reveals  that  ISIS’  ability  to  benefit  from 
these  platforms  was  merely  incidental  to  defendants’  ser-
vices and general business models; it was not attributable 
to any culpable conduct of defendants directed toward ISIS.
And, when considering the fourth and fifth factors (the de-
fendants’ relationship to ISIS and the defendants’ state of 
mind),  the Ninth  Circuit  should have  given  much  greater 
weight to defendants’ arm’s-length relationship with ISIS—
which was essentially no different from their relationship