Document ID: ./input/supremecourt_opinions/opinions/22pdf/21-1496_d18f.pdf
Page Number: 25

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

19 

Opinion of the Court 

as plaintiffs contend, that a defendant have given substan-
tial assistance to a transcendent “enterprise” separate from
and floating above all the actionable wrongs that constitute
it.  Rather,  a  defendant  must  have  aided  and  abetted  (by 
knowingly  providing  substantial  assistance)  another  per-
son in the commission of the actionable wrong—here, an act 
of international terrorism.  See, e.g., Restatement (Second) 
of Torts §876(b), and Comment d; Halberstam, 705 F. 2d, at 
488. 

Plaintiffs insist that Halberstam proves the contrary, but
their  argument  misses  the  gist  of  that  case.  To  be  sure, 
Linda  Hamilton  was  not  on  the  scene  for  the  burglary  of 
Halberstam’s house and did not lend any specific support to 
Halberstam’s murder.  Ibid.  But Hamilton’s assistance to 
Welch was so intentional and systematic that she assisted 
each and every burglary committed by Welch; any time that
Welch left the house to burglarize, he would have relied on 
Hamilton’s  assistance  in  laundering  the  stolen  goods  and 
transforming  them  into  usable  wealth.  See  ibid.    Thus,  
Hamilton  did  aid  and  abet  Welch  in  burglarizing  Hal-
berstam’s home—and, as noted above, killing Halberstam 
was a foreseeable consequence of that burglary.  See ibid. 

On the other hand, defendants overstate the nexus that 
§2333(d)(2) requires between the alleged assistance and the
wrongful act.  To start, aiding and abetting does not require
the defendant to have known “all particulars of the primary
actor’s  plan.”    Restatement  (Third)  of  Torts:  Intentional
Torts to Persons §10, Comment c, p. 104 (Tent. Draft No. 3, 
Apr. 6, 2018).  For example, a defendant might be held lia-
ble for aiding and abetting the burning of a building if he 
intentionally helped others break into the building at night 
and then, unknown to him, the others lit torches to guide 
them through the dark and accidentally started a fire.  See 
American  Family  Mutual  Ins.  Co.  v.  Grim,  201  Kan.  340, 
345–347, 440 P. 2d 621, 625–626 (1968); Restatement (Sec-
ond) of Torts §876, Comment d, Illus. 10, at 318.  That leads