Document ID: ./input/supremecourt_opinions/opinions/22pdf/21-1496_d18f.pdf
Page Number: 23.0

Cite as:  598 U. S. ____ (2023) 

17 

Opinion of the Court 

and  factors  as  a  way  to  synthesize  the  common-law  ap-
proach  to  aiding  and  abetting.    And  JASTA  employs  the 
common-law  terms  “aids  and  abets,”  pointing  to  Hal-
berstam’s common-law “framework” as the primary guide-
post for understanding the scope of §2333(d)(2). 

At bottom, both JASTA and Halberstam’s elements and 
factors rest on the same conceptual core that has animated 
aiding-and-abetting liability for centuries: that the defend-
ant consciously and culpably “participate[d]” in a wrongful
act so as to help “make it succeed.”  Nye & Nissen, 336 U. S., 
at 619.  To be sure, nuances may establish daylight between 
the rules for aiding and abetting in criminal and tort law;
we have described the doctrines as “rough[ly] simila[r],” not
identical.  Central Bank of Denver, 511 U. S., at 181.  But 
we need not resolve the extent of those differences today; it 
is enough for our purposes to recognize the framework that 
Halberstam set forth and the basis on which it rests.  The 
phrase “aids and abets” in §2333(d)(2), as elsewhere, refers 
to a conscious, voluntary, and culpable participation in an-
other’s wrongdoing. 

B 
The next question, however, is what precisely a defend-
ant must aid and abet.  As noted above, JASTA imposes li-
ability on anyone “who aids and abets, by knowingly provid-
ing substantial assistance, or who conspires with the person 
who  committed  such  an  act  of  international  terrorism.” 
§2333(d)(2).  The parties vigorously dispute the textual ob-
ject of the term “aids and abets”: Plaintiffs assert that it is
“the person,” and defendants insist that it is the “act of in-
ternational  terrorism.”    So,  plaintiffs  contend,  defendants 
can  be  liable  if  they  aided  and  abetted  ISIS  generally—
there is no need for defendants to have aided and abetted 
the specific Reina nightclub attack.  Conversely, defendants
posit  that  they  are  liable  only  if  they  directly  aided  and