Amicus Curiae Brief — Twitter, Inc., Petitioner v. Mehier Taamneh, et al.

Supreme Court briefDec 6, 2022

Ask Donna

What actually matters in this document.

Text

No. 21-1496

In the Supreme Court of the United States

TWITTER, INC., PETITIONER

MEHIER TAAMNEH, ET AL.

ON WRIT OF CERTIORARI

TO THE UNITED STATES COURT OF APPEALS

FOR THE NINTH CIRCUIT

BRIEF FOR THE UNITED STATES AS AMICUS CURIAE

IN SUPPORT OF REVERSAL

BRIAN H. FLETCHER

Acting Solicitor General

Counsel of Record

MICHAEL D. GRANSTON

Deputy Assistant Attorney

General

EDWIN S. KNEEDLER

Deputy Solicitor General

ERICA L. ROSS

Assistant to the Solicitor

General

SHARON SWINGLE

JENNIFER L. UTRECHT

Attorneys

Department of Justice

Washington, D.C. 20530-0001

SupremeCtBriefs@usdoj.gov

(202) 514-2217

QUESTIONS PRESENTED

The Antiterrorism Act of 1990 (ATA), 18 U.S.C. 2331

et seq., authorizes United States nationals “injured

* * * by reason of an act of international terrorism” to

recover treble damages for their injuries. 18 U.S.C.

2333(a). The Justice Against Sponsors of Terrorism

Act, Pub. L. No. 114-222, 130 Stat. 852, amended the

ATA to provide that in an action under the ATA for “injury arising from an act of international terrorism committed, planned, or authorized by” a foreign terrorist

organization, “liability may be asserted as to any person

who aids and abets, by knowingly providing substantial

assistance, or who conspires with the person who committed such an act of international terrorism.” 18 U.S.C.

2333(d)(2). The questions presented are:

1. Whether plaintiffs plausibly allege that defendants aided and abetted an act of international terrorism

through the knowing provision of substantial assistance, in violation of 18 U.S.C. 2333(d)(2), based on defendants’ provision of widely available social media services and their failure to actively screen for use of those

services by terrorist organizations and individuals affiliated with them.

2. Whether plaintiffs plausibly allege aiding-andabetting liability in the absence of allegations that defendants’ widely available social media services were

used in connection with the act of international terrorism that caused plaintiffs’ injuries.

(I)

TABLE OF CONTENTS

Page

Interest of the United States....................................................... 1

Statement:

A. Legal framework ............................................................. 2

B. Factual and procedural background .............................. 4

Summary of argument ............................................................... 11

Argument..................................................................................... 13

I. Plaintiffs do not plausibly allege the knowledge

and substantial assistance required for aiding-andabetting liability:

A. JASTA and Halberstam require knowing and

substantial assistance ............................................. 14

B. The knowing-and-substantial assistance

requirement takes on particular importance

where the theory of liability rests on the

defendant’s routine business activities or

inaction ..................................................................... 17

C. Plaintiffs do not plausibly allege that

defendants knowingly provided substantial

assistance to the Reina attack ............................... 23

II. JASTA’s aiding-and-abetting standard focuses on

the act that injured the plaintiff, but does not

necessarily require that the defendant knew about

or specifically aided that act:

A. Aiding-and-abetting liability under the ATA

focuses on the “act of international terrorism”

itself .......................................................................... 31

B. A plaintiff need not necessarily show that the

defendant knew about or provided aid specific

to the particular terrorist attack that injured

the victim .................................................................. 33

Conclusion ................................................................................... 35

(III)

TABLE OF AUTHORITIES

Cases:

Page

Abbott v. Equity Grp., Inc., 2 F.3d 613 (5th Cir.

1993), cert. denied, 510 U.S. 1177 (1994) .......................... 20

Aetna Cas. & Sur. Co. v. Leahey Const. Co.,

219 F.3d 519 (6th Cir. 2000) ............................................. 28

Atchley v. AstraZeneca UK Limited,

22 F.4th 204 (D.C. Cir. 2022) ....................................... 22, 34

Boim v. Holy Land Found. for Relief & Dev.,

549 F.3d 685 (7th Cir. 2008), cert. denied,

558 U.S. 981 (2009)................................................................ 2

Camp v. Dema, 948 F.2d 455 (8th Cir. 1991) ...................... 20

Central Bank, N. A. v. First Interstate Bank, N. A.,

511 U.S. 164 (1994).............................................................. 19

Crosby v. Twitter, Inc., 921 F.3d 617 (6th Cir. 2019) ......... 23

Fields v. Twitter, Inc., 881 F.3d 739 (9th Cir. 2018) ............ 7

Gonzalez v. Google, 2 F.4th 871 (9th Cir. 2021),

cert. granted, No. 21-1333 (Oct. 3, 2022) ............................ 8

Halberstam v. Welch, 705 F.2d 472

(D.C. Cir. 1983) .......................................................... passim

Investors Research Corp. v. SEC,

628 F.2d 168 (D.C. Cir.), cert. denied,

449 U.S. 919 (1980).............................................................. 18

Kaplan v. Lebanese Canadian Bank, SAL,

999 F.3d 842 (2d Cir. 2021) .......................................... 21, 22

Metge v. Baehler, 762 F.2d 621 (8th Cir. 1985) ............... 28

Monsen v. Consolidated Dressed Beef Co.,

579 F.2d 793 (3d Cir.), cert. denied,

439 U.S. 930 (1978).............................................................. 20

Rothstein v. UBS AG, 708 F.3d 82 (2d Cir. 2013) ................ 2

Weiss v. National Westminster Bank PLC:

381 F. Supp. 223 (E.D.N.Y. 2019) .................................. 21

Cases—Continued:

Page

993 F.3d 144 (2d Cir. 2021), cert. denied,

142 S. Ct. 2866 (2022) .......................................... 18, 21

Woodward v. Metro Bank of Dallas,

522 F.2d 84 (5th Cir. 1975) ........................................... 19, 20

Statutes:

Antiterrorism Act of 1990, 18 U.S.C. 2331 et seq. ................ 1

18 U.S.C. 2331(1) ............................................................... 2

18 U.S.C. 2333(a) ............................................... 2, 3, 11, 31

18 U.S.C. 2333(d) ............................................................. 18

18 U.S.C. 2333(d)(2) ............................................... passim

Communications Decency Act of 1996, 47 U.S.C. 230 ......... 8

Justice Against Sponsors of Terrorism Act,

Pub. L. No. 114-222, 130 Stat. 852 ...................................... 2

§2(a)(5), 130 Stat. 852 .................................................. 4, 11

18 U.S.C. 2333 note ......................................... 4, 11, 15, 33

Securities Exchange Act of 1934, 15 U.S.C. 78j(b) ........ 19

18 U.S.C. 2339B .................................................... 3, 18, 21, 32

28 U.S.C. 1605B .................................................................... 26

28 U.S.C. 1605B(b) ............................................................... 26

28 U.S.C. 1605B(c) ............................................................... 26

28 U.S.C. 1605B(d) ............................................................... 26

Miscellaneous:

Black’s Law Dictionary (10th ed. 2014) .................... 16, 32

Restatement (Second) of Torts (1979) ........................... 16, 28

In the Supreme Court of the United States

TWITTER, INC., PETITIONER

MEHIER TAAMNEH, ET AL.

ON WRIT OF CERTIORARI

TO THE UNITED STATES COURT OF APPEALS

FOR THE NINTH CIRCUIT

BRIEF FOR THE UNITED STATES AS AMICUS CURIAE

IN SUPPORT OF REVERSAL

INTEREST OF THE UNITED STATES

This case concerns the scope of aiding-and-abetting

liability under the Antiterrorism Act of 1990 (ATA), 18

U.S.C. 2331 et seq., as amended by the Justice Against

Sponsors of Terrorism Act (JASTA), Pub. L. No. 114222, 130 Stat. 852. The ATA authorizes a United States

national injured or killed by reason of a terrorist attack

to seek compensation from those who aided and abetted

the attack. The United States has an interest in recognizing appropriate invocations of that cause of action,

which can afford a measure of justice to victims and

their families and encourage private actors to be diligent in guarding against actions that support terrorism.

At the same time, the United States has an interest in

ensuring that the scope of ATA liability is consistent

with Congress’s incorporation of common-law tort principles that limit secondary liability to culpable actors.

(1)

STATEMENT

A. Legal Framework

1. The ATA authorizes United States nationals “injured * * * by reason of an act of international terrorism” to bring a civil action for treble damages in federal

court. 18 U.S.C. 2333(a). The ATA defines “international terrorism” to mean criminal activities that occur

primarily abroad or transcend national boundaries and

that “appear to be intended” to “intimidate or coerce a

civilian population,” to “influence the policy of a government by intimidation or coercion,” or to “affect the conduct of a government by mass destruction, assassination, or kidnapping.” 18 U.S.C. 2331(1).

2. Following the ATA’s enactment, courts considered whether the statute made persons who provided

substantial assistance to terrorists civilly liable. Compare Rothstein v. UBS AG, 708 F.3d 82, 97 (2d Cir.

2013), with Boim v. Holy Land Found. for Relief &

Dev., 549 F.3d 685, 688-690 (7th Cir. 2008) (en banc),

cert. denied, 558 U.S. 981 (2009). The United States expressed the view that the ATA imposes secondary liability on defendants who “knowingly provide[] substantial assistance to a terrorist organization,” if the plaintiff “also show[s] that the act of international terrorism

that actually injured the victim was reasonably foreseeable by the defendant.” Gov’t C.A. Amicus Br. at 26-27,

Boim, supra (No. 05-1815) (Boim Br.); see U.S. Amicus

Br. at 7-8, 15 n.6, O’Neill v. Al Rajhi Bank, 573 U.S. 954

(2014) (No. 13-318) (O’Neill Br.). The United States further stated that ATA aiding-and-abetting claims should

be evaluated under tort-law principles, as “summarized

in the seminal D.C. Circuit opinion” in Halberstam v.

Welch, 705 F.2d 472 (1983). Boim Br. at 15-16; see

O’Neill Br. at 7-8.

Halberstam identified three elements of civil aidingand-abetting liability:

(1) the party whom the defendant aids must perform

a wrongful act that causes an injury; (2) the defendant must be generally aware of his role as part of an

overall illegal or tortious activity at the time that he

provides the assistance; [and] (3) the defendant must

knowingly and substantially assist the principal violation.

705 F.2d at 477. Halberstam identified six factors relevant to whether the defendant has furnished substantial

assistance. Id. at 483-484. And Halberstam explained

that secondary liability attaches only where the act that

injures the plaintiff is a “natural and foreseeable consequence” of the “activity” the defendant knowingly and

substantially assisted. Id. at 488; see id. at 484.

The United States further explained in its Boim

brief that while “liability can be imposed under Section

2333(a) if common law tort standards are met even in

the absence of a specific intent by the defendant to assist in acts of international terrorism[,] * * * the defendant’s intent will normally be a substantial factor in

the analysis.” Boim Br. at 2. The United States stated

that “[i]n certain factual situations,” conduct that would

violate 18 U.S.C. 2339B—which makes it a crime to

“knowingly provide[] material support or resources to a

foreign terrorist organization”—“would not support

civil tort liability under Section 2333(a), such as where

the connection between a defendant’s actions and the

act of international terrorism that harms the victim is

insubstantial.” Boim Br. at 3; see id. at 23, 31.

3. In 2016, Congress amended the ATA to expressly

provide for aiding-and-abetting liability. As amended

by JASTA, the ATA states that in an action based on

“an injury arising from an act of international terrorism

committed, planned, or authorized by” a foreign terrorist organization, “liability may be asserted as to any

person who aids and abets, by knowingly providing substantial assistance, or who conspires with the person

who committed such an act of international terrorism.”

18 U.S.C. 2333(d)(2). JASTA further states that Halberstam “provides the proper legal framework for how

[aiding-and-abetting] liability should function in th[is]

context.” § 2(a)(5), 130 Stat. 852 (18 U.S.C. 2333 note).

B. Factual And Procedural Background

1. On January 1, 2017, Abdulkadir Masharipov fired

120 rounds into a crowd at the Reina nightclub in Istanbul, Turkey, killing 39 people and injuring 69 others.

Pet. App. 9a-10a. The Islamic State of Iraq and Syria

(ISIS), a designated foreign terrorist organization,

claimed responsibility for the attack. Id. at 10a.

Plaintiffs (the individual respondents here) are U.S.national family members of Nawras Alassaf, a Jordanian citizen killed in the Reina attack. Plaintiffs

brought this ATA action against three social media

companies—Twitter, Facebook, and Google, which operates YouTube—that they claimed were directly and

secondarily liable for the Reina attack. Pet. App. 3a.

Plaintiffs do not allege that the Reina attack was coordinated or planned via defendants’ social media services. Instead, plaintiffs’ First Amended Complaint

(FAC) alleges that “Google, Twitter, and Facebook

were a critical part of ISIS’s growth.” Pet. App. 10a;

see J.A. 48-53. Plaintiffs allege that ISIS-affiliated accounts first appeared on Twitter in 2010, and that ISIS

has used Facebook and YouTube since at least 2012 and

2013, respectively. J.A. 50, 92-93, 99; see Pet. App. 65a.

Plaintiffs further allege that ISIS and its affiliated

media production and distribution networks have

“openly maintained and used official Twitter, Facebook,

and YouTube accounts” to recruit, radicalize, and instruct terrorists, fund terrorism, and spread propaganda. J.A. 52.

In addition to allegedly hosting ISIS-affiliated accounts and maintaining features by which users may

“follow,” “friend,” or “subscribe” to those accounts, e.g.,

J.A. 87, 92, 97, plaintiffs allege that defendants use

“computer algorithms” to “suggest[]” “content, videos,

and accounts” to users based on their information and

online activities, J.A. 52; see J.A. 143 n.72. According

to plaintiffs, these features permit ISIS to use “Twitter,

Facebook, and YouTube as tools to connect with others

and promote its terrorist activities.” J.A. 147.

Plaintiffs also allege that each defendant “places ads

on ISIS postings and derives revenue for the ad placement,” and that those advertisements are “targeted to

the viewer” by computer algorithms based on “knowledge about the viewer as well as information about the

content being viewed.” J.A. 132. Plaintiffs further allege that through its “AdSense monetization program,”

Google “agrees to share a percentage of the revenue it

generates from ads placed before YouTube videos with

the user who posts the video.” J.A. 139, 140. Plaintiffs

allege that “each video must be reviewed and approved

by Google before Google will permit ads to be placed

with that video.” J.A. 139. Plaintiffs assert that,

“[u]pon information and belief, Google has reviewed and

approved ISIS videos, including videos posted by ISISaffiliated users, for ‘monetization,’ ” and that “Google

has [thus] agreed to share with ISIS and ISIS-affiliated

users a percentage of revenues generated by these

ads.” J.A. 139-140.

Plaintiffs “do not dispute that defendants’ policies

prohibit posting content that promotes terrorist activity

or other forms of violence.” Pet. App. 64a-65a. And

plaintiffs acknowledge that defendants have “suspended or blocked” some ISIS-related accounts. J.A.

135. But plaintiffs allege that prior to the Reina attack,

defendants did not “actively monitor [their] online social media networks * * * to block ISIS’s use of [their]

services,” and “generally only reviewed ISIS’s use of

[their] [s]ervices in response to third party complaints.”

J.A. 134. Plaintiffs allege that “[f]or years, the media

has reported on * * * ISIS’s use of Defendants’ social

media sites and their refusal to take any meaningful action to stop it,” and “both the U.S. government and the

public at large have urged Defendants to stop providing

[their] services to terrorists.” J.A. 88, 90; see J.A. 8891. In addition, plaintiffs allege that in response to specific complaints about ISIS’s use of their platforms, defendants “have at various times determined that ISIS’s

use of [their] [s]ervices did not violate Defendants’ policies,” and “permitted ISIS-affiliated accounts to remain active, or removed only a portion of the content

posted on an ISIS-related account.” J.A. 134-135; see

J.A. 137.

Finally, plaintiffs allege that when defendants removed ISIS content prior to the Reina attack, they “did

not make substantial or sustained efforts to ensure that

ISIS would not reestablish the accounts using new identifiers” that resemble prior ones, despite defendants’ alleged technical ability to “track” and remove such accounts. J.A. 135, 154-155; see J.A. 149-150, 155-156.

2. The district court dismissed the FAC with prejudice. Pet. App. 151a-180a.

As to direct liability, the district court relied on the

Ninth Circuit’s prior determination that by providing a

cause of action for U.S. nationals injured “by reason of

an act of international terrorism,” the ATA requires

proximate causation “between the injuries that [the

plaintiff] suffered and the defendant’s acts.” Pet. App.

164a-165a (quoting Fields v. Twitter, Inc., 881 F.3d 739,

744 (9th Cir. 2018)). Here, the court determined that

plaintiffs’ “conclusory” allegation that Masharipov was

“ ‘radicalized by ISIS’s use of social media’ ” was “insufficient to support a plausible claim of proximate causation.” Id. at 168a (quoting J.A. 157). The court noted

that plaintiffs did not allege that Masharipov maintained an account on defendants’ platforms, nor that

Masharipov “ever saw any specific content on social media related to ISIS.” Ibid.

With respect to aiding-and-abetting liability, the district court first expressed doubt that plaintiffs could

succeed by showing that defendants aided and abetted

ISIS’s terrorist operations in general, “and not the

Reina attack specifically.” Pet. App. 173a. Even if they

could do so, however, the court held that plaintiffs failed

to plausibly allege the second and third elements required by Halberstam. Id. at 175a; see p.3, supra. Regarding defendants’ general awareness, the court viewed

plaintiffs’ allegations that defendants knew “that ISIS

previously recruited, raised funds, or spread propaganda through Defendants’ platforms” as “more akin

to” allegations that defendants provided material support to ISIS, not that they knowingly “assum[ed] a role

in [its] terrorist activities.” Id. at 177a. And with respect to the knowing provision of substantial assistance,

the court pointed to the absence of allegations “that Defendants played a major or integral part in ISIS’s

terrorist attacks”; the “arms-length” nature of the relationship between defendants and ISIS, pursuant to

which defendants “provided routine services generally

available to members of the public” rather than “targeted financial support”; and the lack of allegations

“that Defendants have any intent to further ISIS’s terrorism.” Id. at 177a-179a.

3. Plaintiffs appealed the dismissal of their aidingand-abetting claim. Pet. App. 60a. The court of appeals

decided their appeal along with two separate appeals

concerning claims that social media companies are liable for other terrorist attacks under the ATA, id. at 3a4a, one of which is relevant here.

a. The court of appeals first addressed Gonzalez v.

Google LLC, No. 18-16700 (9th Cir.), cert. granted, No.

21-1333 (Oct. 3, 2022), in which plaintiffs appealed the

dismissal of their claims against Google for both direct

and secondary liability. The court held that the Gonzalez plaintiffs’ claims are barred by the statute commonly

known as Section 230 of the Communications Decency

Act of 1996, 47 U.S.C. 230, except insofar as they rely on

Google’s sharing of advertising revenue with ISIS. Pet.

App. 15a-42a. The court held, however, that the revenuesharing allegations do not state a claim for direct liability. Id. at 42a-46a.

As to aiding-and-abetting liability in Gonzalez, the

court found with respect to the first two Halberstam elements that the plaintiffs plausibly allege that ISIS

committed the relevant attack, and that Google was

“generally aware of its role in ISIS’s terrorist activities

at the time it provided assistance to ISIS.” Pet. App.

50a; see id. at 50a-52a. Regarding the third element,

the court determined that the Gonzalez plaintiffs plausibly allege that Google provided “knowing assistance”

because, inter alia, Google allegedly reviewed videos

before approving advertisements for revenue-sharing.

Id. at 54a (emphasis added); see id. at 54a-55a. The

court determined, however, that plaintiffs fail to plausibly allege that Google’s assistance was substantial because “the [complaint] is devoid of any allegations about

how much assistance Google provided,” and does not allege that “Google intended to assist ISIS.” Id. at 58a.

b. The court of appeals next explained that because

the district court in Taamneh “did not reach § 230,” the

court of appeals would consider all of plaintiffs’ allegations in this case under JASTA and the Halberstam

framework. Pet. App. 60a.

The court of appeals determined that plaintiffs plausibly allege the first Halberstam element: The Reina

Attack was an “ ‘act of international terrorism’ ” that

was “ ‘committed, planned, or authorized’ by ISIS.” Pet.

App. 61a. The court next determined that plaintiffs

plausibly allege that defendants were “generally aware

they were playing an important role in ISIS’s terrorism

enterprise.” Id. at 62a. The court noted plaintiffs’ allegation that “at the time of the Reina Attack, defendants

were generally aware that ISIS used defendants’ platforms to recruit, raise funds, and spread propaganda in

support of their terrorist activities.” Id. at 61a. And

plaintiffs allege that despite “ ‘extensive media coverage’ and legal and governmental pressure, defendants

‘continued to provide these resources and services to

ISIS and its affiliates, refusing to actively identify ISIS

Twitter, Facebook, and YouTube accounts, and only reviewing accounts reported by other social media users.’ ” Id. at 62a (quoting J.A. 52-53).

With respect to the third Halberstam element, the

court of appeals held that plaintiffs adequately allege

that defendants “knowingly” provided assistance. Pet.

App. 62a-66a. The court again pointed to plaintiffs’ allegations that defendants were “aware of ISIS’s use of

their respective social media platforms for many years”

but “refused to take meaningful steps to prevent that

use.” Id. at 62a.

The court of appeals then determined that plaintiffs

plausibly allege that defendants’ assistance to ISIS was

“substantial,” Pet. App. 65a, applying the six Halberstam factors. The court stated that the act subjecting defendants to potential secondary liability was

“ISIS’s terrorism campaign,” and reasoned that that

campaign was “heavily dependent on [the] social media

platforms”; that the assistance provided by those platforms was “integral to ISIS’s expansion, and to its success as a terrorist organization”; and that defendants

provided this assistance for “many years.” Id. at 63a65a. The court acknowledged, however, that defendants

were not present during the Reina attack; that “defendants had, at most, an arms-length transactional relationship with ISIS,” which “may be even further attenuated” because defendants “regularly removed ISIS

content and ISIS-affiliated accounts,” and their policies

“prohibit posting content that promotes terrorist activity or other forms of violence”; and that plaintiffs do not

allege that defendants intended to further ISIS’s terrorist activities. Id. at 64a-65a; see id. at 65a-66a.

c. Judge Berzon issued a concurring opinion, and

Judge Gould issued an opinion concurring in part and

dissenting in part; those separate opinions addressed

the panel’s resolution of the other two appeals. Pet.

App. 72a-150a.

SUMMARY OF ARGUMENT

As amended by JASTA, the ATA authorizes U.S. nationals “injured * * * by reason of an act of international terrorism” committed, planned, or authorized by

a foreign terrorist organization to recover damages

from “any person who aids and abets, by knowingly

providing substantial assistance, or who conspires with

the person who committed” the act. 18 U.S.C. 2333(a)

and (d)(2). JASTA further states that Halberstam v.

Welch, 705 F.2d 472 (D.C. Cir. 1983), provides “the

proper legal framework for how such liability should

function in th[is] context.” § 2(a)(5), 130 Stat. 852 (18

U.S.C. 2333 note). Under the statute’s text and Halberstam, plaintiffs have not plausibly alleged that defendants “aid[ed] and abet[ted], by knowingly providing

substantial assistance” to, the Reina attack, 18 U.S.C.

2333(d)(2).

I. Plaintiffs fail to plausibly allege the knowledge

and substantial assistance required for aiding-andabetting liability.

A. The ATA’s text and Halberstam require that an

aiding-and-abetting defendant “knowingly” provide

“substantial assistance” to unlawful conduct. 18 U.S.C.

2333(d)(2); see Halberstam, 705 F.2d at 477. Halberstam’s discussion of the common law explains that

substantial assistance may take the form of supportive

acts or encouragement, and Halberstam equates aiding

and abetting with conscious participation in wrongdoing. 705 F.2d at 477, 478, 481-485.

B. Halberstam and the decisions on which it relied

make clear that the knowing-and-substantial assistance

requirement is less likely to be satisfied where a defendant provided only routine business services in an ordinary manner, was remote from the unlawful act that

injured the plaintiff, or is accused of aiding and abetting

another’s conduct through inaction. Consistent with

those principles, other courts applying the ATA have

been reluctant to hold an aiding-and-abetting defendant

liable when it provided only widely available services in

the context of an arms-length business relationship.

C. The court of appeals erred in holding that plaintiffs plausibly allege that defendants knowingly provided substantial assistance to the Reina attack. With

respect to knowledge, plaintiffs do not allege that defendants aided ISIS through atypical transactions; nor

do they dispute that defendants’ policies prohibit terrorist content or that defendants removed some ISISrelated content when they became specifically aware of

it. Rather, plaintiffs allege that defendants knew that

ISIS and its affiliates used defendants’ widely available

social media platforms, in common with millions, if not

billions, of other people around the world, and that defendants failed to actively monitor for and stop such

use. Those allegations do not plausibly allege that defendants knowingly provided substantial assistance to

the Reina attack.

The court of appeals’ application of Halberstam’s

substantiality factors was incorrect. Among other

things, the court gave the amount of assistance outsized

weight, seeming to suggest that because social media

platforms were allegedly important to ISIS’s growth

generally, defendants substantially assisted any and all

ISIS terrorist attacks. The court also misconstrued the

import of the duration-of-assistance factor. And it gave

insufficient weight to the arms-length relationship between defendants and ISIS, as well as plaintiffs’ acknowledgment that defendants had no intent to further

its terrorist acts. Properly viewed, defendants’ alleged

actions cannot be deemed a substantial cause of plaintiffs’ injuries.

II. JASTA requires that the defendant aid and abet,

by knowingly providing substantial assistance to, the

act of international terrorism that caused the plaintiffs’

injuries.

A. JASTA permits U.S. nationals to obtain treble

damages from defendants who “aid[] and abet[], by

knowingly providing substantial assistance, or who conspire[] with the person who committed * * * an act of

international terrorism.” 18 U.S.C. 2333(d)(2). That

text focuses on the act of international terrorism itself;

it does not impose liability merely for providing generalized aid to a foreign terrorist organization.

B. Nonetheless, JASTA does not necessarily require

that a defendant knew about the particular terrorist act

in question or provided support specific to it. JASTA

adopts the secondary-liability framework set forth in

Halberstam. And Halberstam makes clear that in some

circumstances, a secondary defendant’s contributions

may have a sufficient nexus to a tortious act even if the

defendant assisted a series of such acts but did not have

advance knowledge of, or provide support specifically

directed to, the particular act that injured the plaintiff.

Plaintiffs’ allegations, however, do not meet that standard.

ARGUMENT

The United States condemns in the strongest terms

the terrorist act that caused Alassaf ’s death and sympathizes with the profound loss plaintiffs have suffered.

In this case, however, the court of appeals erred in holding that plaintiffs’ allegations state a claim that defendants are secondarily liable for the Reina attack under

the ATA. In particular, the FAC fails to plausibly allege

that defendants aided and abetted that attack by the

knowing provision of substantial assistance. In the

United States’ view, such a showing does not necessarily require that an aiding-and-abetting defendant

have had specific knowledge of the particular terrorist

attack that injured the victim, or have provided resources specific to that attack. But JASTA requires

more than generalized support to a terrorist organization through the provision of widely available services.

Plaintiffs’ allegations do not clear that threshold.

I. PLAINTIFFS DO NOT PLAUSIBLY ALLEGE THE

KNOWLEDGE AND SUBSTANTIAL ASSISTANCE

REQUIRED FOR AIDING-AND-ABETTING LIABILITY

Civil liability for aiding and abetting requires a finding that the defendant’s actions affirmatively advanced

or encouraged the commission of the tort in a manner

that rendered the defendant complicit in it. To that end,

JASTA’s plain text and the Halberstam decision it invokes both require that an aiding-and-abetting defendant knowingly provided substantial assistance to the

primary tortfeasor’s wrongful act. The FAC’s allegations do not meet that standard.

A. JASTA And Halberstam Require Knowing And Substantial Assistance

1. JASTA amended the ATA to provide that “liability may be asserted as to any person who aids and abets,

by knowingly providing substantial assistance, or who

conspires with the person who committed” the act of international terrorism that injured the victim. 18 U.S.C.

2333(d)(2) (emphasis added). The statutory text thus

requires that a defendant’s aiding and abetting be

through the provision of assistance that is both knowing

and substantial. JASTA further explains that the D.C.

Circuit’s decision in Halberstam v. Welch, 705 F.2d 472

(1983), “provides the proper legal framework for how

such liability should function.” 18 U.S.C. 2333 note.

Halberstam likewise requires a showing of knowing and

substantial assistance.

“The scenario presented in Halberstam is, to put it

mildly, dissimilar to the one at issue here.” Pet. App.

48a. In Halberstam, the D.C. Circuit considered

whether Linda Hamilton could be held liable for aiding

and abetting an unplanned murder that her live-in partner, Michael Welch, committed during a burglary. The

court explained that Welch had committed “innumerable burglaries” over five years, and that Hamilton

served as “banker, bookkeeper, recordkeeper, and secretary” for that series of burglaries, helping to launder

the “fortune” she and Welch acquired by selling his stolen goods. 705 F.2d at 474, 476, 486-487. Buyers “made

their checks payable to [Hamilton],” and she deposited

them into her own bank accounts. Id. at 475. She also

kept records of these “asymmetrical transactions—

which included payments coming in from buyers, but no

money going out to the sellers from whom Welch had

supposedly bought the goods.” Ibid. Hamilton further

knew that Welch “installed a smelting furnace in the

garage and used it to melt gold and silver into bars.”

Ibid. Given this evidence, the court of appeals credited

the district court’s factual findings that although Hamilton did not intend the murder, she “knew full well the

purpose of Welch’s evening forays” and “was a willing

partner in his criminal activities.” Id. at 486 (brackets

and citation omitted); see id. at 474, 488.

To determine whether those facts sufficed for aidingand-abetting liability, Halberstam canvassed the

common-law jurisprudence. See 705 F.2d at 489. The

court identified three elements of a civil aiding-andabetting claim: First, “the party whom the defendant

aids must perform a wrongful act that causes an injury.”

Id. at 477. Second, “the defendant must be generally

aware of his role as part of an overall illegal or tortious

activity at the time that he provides the assistance.”

Ibid. Third, “the defendant must knowingly and substantially assist the principal violation.” Ibid. Consistent with the common law, the court indicated that its

three-part test for aiding-and-abetting liability requires

conscious participation in the wrongdoing. See id. at

477 (quoting Restatement (Second) of Torts § 876(b)

(1979)) (person is secondarily liable if he “knows that

the other’s conduct constitutes a breach of duty and

gives substantial assistance or encouragement to the

other so to conduct himself ”); id. at 479, 481, 482, 483,

484, 488; see also Black’s Law Dictionary 4 (10th ed.

2014) (“abet”: “To aid, encourage, or assist (someone).”); id. at 84 (“aid and abet”: “To assist or facilitate

the commission of a crime, or to promote its accomplishment.”).

2. The Halberstam court found all three elements

set out in its opinion met. First, Welch performed a

wrongful act that caused an injury by murdering Halberstam during a burglary. 705 F.2d at 488. Second,

the district court’s “conclusions that Hamilton knew

about and acted to support Welch’s illicit enterprise”

were sufficient to “establish that Hamilton had a general awareness of her role in a continuing criminal enterprise.” Ibid.; see id. at 487-488.

The third element required a more extensive analysis. Halberstam, 705 F.2d at 488. Although Hamilton

might not have known of any particular burglary in advance, the court of appeals held that the district court

“justifiably inferred that Hamilton assisted Welch with

knowledge that he had engaged in illegal acquisition of

goods.” Ibid. The court observed that Hamilton provided “invaluable service to the enterprise as banker,

bookkeeper, recordkeeper, and secretary,” and that she

had “performed these services in an unusual way under

unusual circumstances for a long period of time.” Id. at

487 (holding that the district court’s finding of “knowing assistance” was not clearly erroneous).

Thus, the only remaining issue was whether “Hamilton’s assistance was * * * substantial enough to justify

liability on an aider-abettor theory.” Halberstam, 705

F.2d at 488. Applying six factors it had discerned from

the common law, the court determined that it was. Ibid.

“[A]lthough the amount of assistance” Hamilton provided may not have been “overwhelming as to any given

burglary, it added up over time to an essential part of

the pattern.” Ibid. Hamilton’s state of mind “assume[d] a special importance,” and the duration of her

assistance also “strongly influenced” the court’s conclusion: Hamilton’s “continuous participation reflected

her intent and desire to make the venture succeed; it

was no passing fancy or impetuous act.” Ibid. Finally,

Halberstam determined that Hamilton was liable for

the murder because “violence and killing” were a reasonably foreseeable consequence of the activity she had

helped Welch to undertake. Ibid.

B. The Knowing-and-Substantial Assistance Requirement

Takes On Particular Importance Where The Theory Of

Liability Rests On The Defendant’s Routine Business

Activities Or Inaction

1. As Halberstam explained, “an ‘awareness of

wrong-doing requirement’ for an aider-abettor is designed to avoid subjecting innocent, incidental

participants to harsh penalties or damages.” 705 F.2d

at 485 n.14 (quoting Investors Research Corp. v. SEC,

628 F.2d 168, 177-178 (D.C. Cir.), cert. denied, 449 U.S.

919 (1980)). JASTA incorporates a knowledge requirement twice over: It requires that the defendant “knowingly provid[e] substantial assistance,” 28 U.S.C.

2333(d)(2), and it invokes the Halberstam framework

and thus adopts its similar mens rea requirements.

In terms of what a defendant must know, JASTA

makes clear that it is not sufficient for a defendant to

knowingly provide material support to a foreign terrorist organization, as would suffice for criminal liability

under Section 2339B. See, e.g., Weiss v. National Westminster Bank PLC, 993 F.3d 144, 165 (2d Cir. 2021),

cert. denied, 142 S. Ct. 2866 (2022); see pp. 31-32, infra.

Rather, Section 2333(d)’s “knowing” requirement modifies the defendant’s own substantial assistance to the

commission of a terrorist act that injured the plaintiff.

Thus, the statute requires “the secondary actor to be

aware that, by assisting the principal, it is itself assuming a role in terrorist activities.” Ibid. (internal quotation marks omitted). JASTA does not necessarily require that the defendant knew of any particular terrorist attack before it occurred—just as Hamilton did not

necessarily know in advance of any particular burglary.

See pp. 33-34, infra. But a court must at least be able

to infer that the secondary defendant was aiding and

abetting terrorist acts by knowingly providing substantial support to their commission.

2. Halberstam provides significant guidance for that

inquiry. The decision strongly suggests that courts may

more readily infer the requisite knowledge and find a

defendant’s support sufficiently substantial where the

secondary defendant engaged in atypical conduct linked

to the principal violator’s wrongful acts than if she had

provided generally available business services through

ordinary arms-length transactions. Halberstam affirmed the district court’s “inference of knowing assistance” in part because Hamilton provided services in

connection with Welch’s burglaries “in an unusual way

under unusual circumstances for a long period of time”;

“their activities were symbiotic,” and they “performed

some of their different parts of the illegal operation together at the same location.” 705 F.2d at 487; see ibid.

(finding that Hamilton “knew she was assisting Welch’s

wrongful acts”). By contrast, had Hamilton been an ordinary “banker, bookkeeper, recordkeeper, [or] secretary,” ibid., processing ordinary transactions at arm’s

length in the regular course of a business separate from

Welch’s undertakings, it would have been more difficult

to conclude that she aided and abetted—that is, knowingly and substantially assisted—Welch’s burglaries.

Halberstam relied on securities-law cases that likewise distinguished between routine and atypical transactions, at a time before this Court held that Section 10b

of the Securities Exchange Act of 1934, 15 U.S.C. 78j(b),

does not create a private right of action for aiding and

abetting. See Central Bank, N. A. v. First Interstate

Bank, N.A., 511 U.S. 164, 169 (1994). For example, in

Woodward v. Metro Bank of Dallas, 522 F.2d 84 (1975),

the Fifth Circuit explained that “[i]f the alleged aider

and abettor conducts what appears to be a transaction

in the ordinary course of his business, more evidence of

his complicity is essential.” Id. at 95 (discussing the

general-awareness requirement); see Halberstam, 705

F.2d at 477 & n.8, 485 n.14. Woodward made similar

statements in evaluating whether “silence and inaction”

can constitute the knowing provision of substantial

assistance (a question Halberstam left open, 705 F.2d

at 485 n.14). See Woodward, 522 F.2d at 96-97. And in

Monsen v. Consolidated Dressed Beef Co., 579 F.2d 793

(3d Cir.), cert. denied, 439 U.S. 930 (1978)—which Halberstam also cited—the court explained that “inaction

* * * may provide a predicate for liability where the

plaintiff demonstrates that the aider-abettor [c]onsciously intended to assist in the perpetration of a

wrongful act.” Id. at 800; see Halberstam, 705 F.2d at

478 (citing Monsen).

Woodward likewise explained that “[t]he scienter requirement scales upward when activity is more remote”

from the legal violation. 522 F.3d at 95. “A remote

party must not only be aware of his role, but he should

also know when and to what degree he is furthering the

fraud.” Ibid.

Following Halberstam, other courts made a similar

point. For example, in Camp v. Dema, 948 F.2d 455

(1991), the Eighth Circuit stated that knowledge, which

“permeates” both the second and third requirements

for aiding-and-abetting liability, is essential to distinguish “aiding and abetting * * * from simply aiding,”

because “ ‘abet’ ” entails some measure of encouragement. Id. at 459 (citation omitted). The court explained

that “[a] party who engages in atypical business transactions or actions which lack business justification may

be found liable as an aider and abettor with a minimal

showing of knowledge,” whereas “a party whose actions

are routine and part of normal everyday business practices would need a higher degree of knowledge for liability as an aider and abettor to attach.” Ibid.; see, e.g.,

Abbott v. Equity Grp., Inc., 2 F.3d 613, 621 (5th Cir.

1993), cert. denied, 510 U.S. 1177 (1994).

3. Courts applying JASTA’s secondary-liability provision have followed the same approach: They have

been reluctant to find remote defendants liable for aiding and abetting an act of terrorism based on allegations

that they provided routine business services through

arms-length transactions, but more willing to impose liability for atypical services provided in an atypical way.

In Weiss, for example, the Second Circuit sustained

the district court’s holding that it would be futile for

plaintiffs to amend their complaint to add an aidingand-abetting claim against a financial institution that

provided routine services to charities suspected of affiliation with Hamas. The district court explained that

“[e]vidence that Defendant knowingly provided banking services to a terrorist organization,” in violation of

Section 2339B, “without more, is insufficient to satisfy

JASTA’s scienter requirement.” Weiss v. National

Westminster Bank PLC, 381 F. Supp. 223, 239 (E.D.N.Y.

2019). In affirming, the court of appeals explained that

the plaintiffs could not show that the bank was “knowingly providing substantial assistance to Hamas, or that

[it] was generally aware that it was playing a role in Hamas’s acts of terrorism,” where it investigated allegations that specific customers were aiding Hamas, and

there was no evidence that the bank knew of any transfer made for a terroristic purpose. Weiss, 993 F.3d at

165; see id. at 166-167.

By contrast, in Kaplan v. Lebanese Canadian Bank,

SAL, 999 F.3d 842 (2021), the Second Circuit held that

a plaintiff sufficiently pleaded an aiding-and-abetting

claim against a bank. The complaint there did not allege

the provision of only “routine banking services,” id. at

858 (citation omitted); rather, it alleged that the bank

provided “special treatment” to particular customers

that were “ ‘openly, publicly and repeatedly acknowledged and publicized’ ” as being integral parts of Hezbollah, and did so in “knowing violation of banking regulations,” which allowed the customers to “circumvent[]

sanctions imposed in order to hinder terrorist activity.”

Id. at 850, 862, 866 (citations and emphases omitted).

The court determined that these allegations of individualized treatment “adequately pleaded that [the defendant] knowingly gave the Customers assistance that

both aided H[e]zbollah and was qualitatively and quantitatively substantial.” Id. at 866.

In other contexts, too, courts have found JASTA’s

knowing-and-substantial assistance requirement more

easily met where defendants engaged in transactions

outside the regular course of business. In Atchley v.

AstraZeneca UK Limited, 22 F.4th 204 (2022), the D.C.

Circuit held that plaintiffs plausibly alleged aiding-andabetting liability based on claims that defendants secured lucrative medical-supply contracts by giving an

entity affiliated with a known terrorist group millions of

dollars in cash kickbacks, as well as medical goods that

defendants knew would be sold on the black market to

fund terrorism. Id. at 221-222. The court analogized to

Halberstam, in which Hamilton “performed her otherwise-innocuous services for [Welch] ‘in an unusual way

under unusual circumstances.’ ” Id. at 221 (quoting Halberstam, 705 F.2d at 487). So too, in Atchley, “the corrupt provision of free goods and cash bribes to an entity

defendants knew was engaged in anti-American acts of

terrorism” supported an inference of the requisite mens

rea. Ibid.; see id. at 223 (similar discussion in substantiality analysis). 1

Atchley grounded its mens rea discussion in the defendant’s

general awareness of its role in facilitating terrorism. Atchley, 22

C. Plaintiffs Do Not Plausibly Allege That Defendants

Knowingly Provided Substantial Assistance To The

Reina Attack

Under these principles, the court of appeals erred in

determining that plaintiffs plausibly allege that defendants knowingly provided substantial assistance to the

Reina attack.

1. a. As to knowledge, plaintiffs do not allege that

specific accounts on their platforms were being used to

plot or prepare for the Reina attack or for attacks that

included Reina, or that defendants knew of any such accounts.2 Cf. J.A. 117-118. Nor do plaintiffs plausibly

allege that defendants aided and abetted the Reina attack or other ISIS terrorist attacks by, for example,

knowingly bending their normal policies to treat ISIS

and its affiliates differently from the millions (or billions) of other users of their services so to facilitate

those attacks. Instead, most of plaintiffs’ allegations

F.4th at 221-222; cf. Kaplan, 999 F.3d at 863-864. In the United

States’ view, whether the defendant engaged in atypical business

transactions is likewise relevant to whether a court may infer that a

defendant knowingly provided substantial assistance.

Plaintiffs more generally allege that Masharipov was “radicalized by ISIS’s use of social media.” J.A. 157; see J.A. 158. Such an

allegation, standing alone, is insufficient to suggest that defendants

knowingly provided substantial assistance to the Reina attack. See,

e.g., Crosby v. Twitter, Inc., 921 F.3d 617, 625 (9th Cir. 2019) (explaining that a contrary holding would make social media companies

“liable for seemingly endless acts of modern violence”). And even if

it could, the FAC is devoid of facts to substantiate that “conclusory

allegation.” Pet. App. 168a. Plaintiffs do not allege that Masharipov

“ever saw any specific content on social media related to ISIS,” or

that he “maintained a Facebook, YouTube, and/or Twitter account.”

Ibid. Instead, the FAC suggests other potential sources of

Masharipov’s radicalization, including his military training with alQaeda and maintenance of ISIS contacts in Syria. J.A. 118-119.

indicate that defendants made their social media platforms available to anyone with access to the Internet;

that although defendants’ “policies prohibit posting

content that promotes terrorist activity,” Pet. App. 64a65a, ISIS and its affiliates used defendants’ services;

and that although defendants generally removed terrorist content and accounts when they had specific

knowledge of them, defendants failed to affirmatively

search for and remove such content. See Br. in Opp. 1718; see Pet. App. 64a; pp. 26-27, infra (addressing additional allegations). Plaintiffs further allege that defendants continued to make their social media platforms

available in this manner despite media reports that

ISIS and its affiliates used their services, as well as government encouragement to take more aggressive action

against ISIS-affiliated content. E.g., J.A. 88-91; see Br.

in Opp. 15-16.

A defendant’s knowing complicity in a terrorist

group’s illegal activities can, in some circumstances,

give rise to aiding-and-abetting liability. Here, however, most of plaintiffs’ allegations suggest only that defendants were aware that some ISIS-affiliated users

and ISIS content remained on their platforms, along

with millions (or billions) of other users and pieces of

content, and that defendants did not search for and remove those users and content. These allegations differ

substantially from the provision of atypical and particularized services that furnished the basis for finding the

requisite mens rea and substantial support with respect

to the conduct that injured the plaintiff in Halberstam

and the cases discussed above. They are insufficient to

plausibly allege that defendants knowingly provided

substantial support to the Reina attack.

b. Much of plaintiffs’ theory of liability rests on the

proposition that ISIS’s overall success is “heavily dependent” upon its use of social media services. Halberstam, 705 F.2d at 488. From this predicate, plaintiffs

contend that the ATA’s aiding-and-abetting provision

imposes on defendants an affirmative obligation in tort

to “actively monitor” for ISIS-affiliated accounts and

postings generally, and to make “substantial or sustained efforts to ensure that ISIS would not reestablish” deleted accounts “using new identifiers.” J.A. 134135; see, e.g., J.A. 155. Plaintiffs thus contend that although defendants generally removed ISIS-related content in response to complaints, their failure to do more,

despite general reporting of ISIS’s use of their services,

is sufficient to make them liable for aiding and abetting

ISIS’s commission of terrorist acts. But as discussed

above, the common-law principles Congress incorporated into Section 2333(d)(2) would at least require

more meaningful allegations of direct knowledge for the

failure to take such measures to result in liability for

aiding-and-abetting terrorist acts. Treating such “inaction” in the context of generalized information as proof

of the requisite knowledge—and thus imposing,

through the ATA’s civil-liability provisions, an affirmative duty to monitor—would be particularly inappropriate in this context, where defendants’ social media platforms are used by millions (or billions) of people worldwide.3

Defendants suggest that under the court of appeals’ decision, a

foreign state could be sued in a United States court “if it takes insufficiently ‘meaningful’ or ‘aggressive’ steps to stamp out known

terrorist activity within its borders, so long as a designated terrorist

organization that benefited from that policy later committed an act

of terrorism within the United States.” Google/Facebook Br. 47

c. At times, plaintiffs frame a subset of their allegations more affirmatively. Plaintiffs suggest (J.A. 147)

that defendants’ algorithms promote connections and

interactions among otherwise independent users, which

could amplify communication of ISIS messaging to sympathetic audiences. See Pet. App. 103a-104a (Gould, J.,

concurring in part and dissenting in part). But plaintiffs

describe those algorithms as an automated part of defendants’ widely available services; the automatic instigation of such effects does not show that defendants

knowingly provided substantial assistance to terrorist

acts that persons affiliated with ISIS might commit.

Plaintiffs further allege that defendants “have at

various times” reviewed certain posts or accounts

flagged for violation of their policies against promoting

terrorist activity and determined that the content did

not violate the policies “or removed only a portion of the

content posted on an ISIS-related account.” J.A. 134135; see J.A. 137. But plaintiffs do not provide any details regarding the content that allegedly remained, and

(quoting Pet. App. 62a). As defendants note (ibid.), 28 U.S.C. 1605B

provides an exception to foreign sovereign immunity in an ATA action for physical injuries or death if those injuries are “caused by”

“(1) an act of international terrorism in the United States; and (2) a

tortious act or acts of the foreign state” or its officials, employees,

or agents acting in the scope of their office. 28 U.S.C. 1605B(b) and

(c). Section 1605B also includes a “[r]ule of [c]onstruction”: “A foreign state shall not be subject to the jurisdiction of the courts of the

United States” under Section 1605B(b) “on the basis of an omission

or a tortious act or acts that constitute mere negligence.” 28 U.S.C.

1605B(d). This case does not present the questions whether jurisdiction over a foreign state under Section 1605B extends to claims

based on aiding-and-abetting liability, or whether a failure to take

sufficiently “meaningful” or “aggressive” measures against a terrorist organization could meet the jurisdictional threshold under

that provision and its rule of construction.

they do not suggest how the remaining content would

have substantially assisted the Reina attack or other

acts of terrorism. This Court therefore need not determine whether such allegations could plausibly allege the

knowing provision of substantial assistance in other circumstances.4

2. With respect to substantial assistance in particular, the court of appeals erred for similar reasons in

holding that plaintiffs plausibly allege that defendants’

assistance was “substantial enough to justify liability on

an aider-abettor theory.” Halberstam, 705 F.2d at 488.

Halberstam delineated six factors that govern the

substantiality analysis: (i) the nature of the act assisted,

(ii) the amount and kind of assistance, (iii) the defendant’s presence at the time of the tort, (iv) the defendant’s relationship to the tortious actor, (v) the defendant’s state of mind, and (vi) the duration of assistance.

705 F.2d at 483-484. As courts have explained, the “substantial assistance” factor effectively requires plaintiffs

to show that “the secondary party proximately caused

Plaintiffs also allege that Google (but not the other defendants)

shared advertising revenue with ISIS, which required Google to review ISIS-affiliated videos. See J.A. 137-138. Even if those allegations plausibly alleged that Google knew it was providing ISIS with

some financial assistance, see Pet. App. 62a-63a; but see id. at 65a

(stating that “the articles incorporated into the complaint suggest

that Google took at least some steps to prevent ads from appearing

on ISIS videos”), they would not plausibly allege substantial assistance because the FAC includes “no information” about the number

or content of allegedly approved videos or the “amount of [financial]

assistance provided by Google.” Id. at 56a (so holding regarding

financial assistance in Gonzalez). Accordingly, this case provides no

occasion for this Court to consider the circumstances under which

allegations that a defendant knowingly provided substantial funding

to a terrorist organization might be liable for aiding and abetting a

terrorist act of the organization.

the violation,” i.e., that a “substantial causal connection” existed “between the culpable conduct” of the alleged aider and abettor “and the harm to the plaintiff ”

or that “the encouragement or assistance is a substantial factor in causing the resulting tort.” Metge v. Baehler, 762 F.2d 621, 624 (8th Cir. 1985) (internal quotation

marks omitted); see, e.g. Aetna Cas. & Sur. Co. v.

Leahey Const. Co., 219 F.3d 519, 537 (6th Cir. 2000); see

also Restatement (Second) of Torts § 876 cmt. d (1979).

In considering whether plaintiffs adequately alleged

that defendants provided substantial assistance, the

court of appeals primarily relied on plaintiffs’ allegations that “defendants provided services that were central to ISIS’s growth and expansion, and that this assistance was provided over many years,” counting the

first, second, and sixth factors in plaintiffs’ favor. Pet.

App. 65a; see id. at 63a-65a.

That analysis was flawed. The court gave the

amount of ISIS’s or its adherents’ general use of defendants’ services predominant weight, seeming to suggest that because social media platforms were allegedly

important to ISIS’s growth generally, defendants substantially assisted any terrorist attack by ISIS anywhere in the world. Pet. App. 63a-64a. But the amount

of assistance—which must be considered in light of the

kind of assistance—is only one of the six substantiality

factors, and it must take into account the degree of connection between the assistance provided and the ultimate act. See Halberstam, 705 F.2d at 484 (discussing

cases in which the aider and abettor played a “major

part in prompting the tort” or provided “integral” support to it).

Similarly, Halberstam explained that the first factor

—the “nature of the act involved”—“dictates what aid

might matter, i.e., be substantial.” 705 F.2d at 484 (emphasis omitted). The murder in Halberstam was committed during one of a long series of burglaries that

Welch committed, and the court emphasized that “the

success of the tortious enterprise clearly required

[Hamilton’s] expeditious and unsuspicious disposal of

the goods.” Id. at 488. Here, the court of appeals again

gave great weight to plaintiffs’ allegations that ISIS

and its adherents have made significant use of defendants’ platforms, without accounting for the fact that

those platforms were widely available; that the assistance ISIS derived was automatic, not particularized;

and that the assistance was far more remote from terrorist attacks by ISIS than Hamilton’s assistance was

from Welch’s burglaries. Pet. App. 65a. The court of

appeals thus gave too much weight to the second factor,

even accounting for the heinous nature of the Reina attack. See Halberstam, 705 F.2d at 484 n.13.

As to the period of assistance, Halberstam added

that consideration to the other, then-prevailing five factors. 705 F.2d at 484. The court explained that “[t]he

length of time an alleged aider-abettor has been involved with a tortfeasor” is significant insofar as it interacts with other factors: It may “affect[] the quality

and extent of the[] relationship” between the primary

and alleged secondary tortfeasors; it may “influence[]

the amount of aid provided”; and it “may afford evidence of the defendant’s state of mind.” Ibid. Yet the

court of appeals afforded significant weight to the

length of time that ISIS and its affiliates used defendants’ services, even though it acknowledged that the relationship between defendants and ISIS remained (at

most) arms-length; that defendants provided only

generally available services; and that defendants had no

intent to further ISIS’s terrorist acts.

The remaining factors support defendants based on

plaintiffs’ own admissions. “There is no dispute that defendants were not present during the Reina Attack.”

Pet. App. 64a. As to the defendants’ relationship with

ISIS, plaintiffs “do not dispute that defendants’ policies

prohibit posting content that promotes terrorist activity

or other forms of violence.” Id. at 64a-65a. And plaintiffs’ allegations suggest that “defendants had, at most,

an arms-length transactional relationship with ISIS,”

which may have been “even further attenuated than the

ones defendants have with some of their other users because the FAC alleges defendants regularly removed

ISIS content and ISIS-affiliated accounts.” Id. at 64a;

see id. at 65a (“[T]he record indicates that defendants

took steps to remove ISIS-affiliated accounts and videos.”). Regarding defendants’ state of mind—which the

court of appeals acknowledged is “an important factor”

—plaintiffs allege that defendants allowed some ISIS

content to remain on their platforms, but they “do not

allege that defendants had any intent to further or aid

ISIS’s terrorist activities, or that defendants shared

any of ISIS’s objectives.” Id. at 65a.

In sum, plaintiffs’ allegations, properly viewed, fail

to allege that defendants knowingly provided substantial assistance to the Reina attack.

II. JASTA’S AIDING-AND-ABETTING STANDARD FOCUSES ON THE ACT THAT INJURED THE PLAINTIFF,

BUT DOES NOT NECESSARILY REQUIRE THAT THE

DEFENDANT KNEW ABOUT OR SPECIFICALLY

AIDED THAT ACT

A. Aiding-And-Abetting Liability Under The ATA Focuses

On The “Act of International Terrorism” Itself

The ATA’s primary liability provision authorizes a

U.S. national “injured * * * by reason of an act of international terrorism” to recover treble damages from

defendants who commit the act. 18 U.S.C. 2333(a).

JASTA amended Section 2333 to further permit such a

victim to obtain treble damages from “any person who

aids and abets, by knowingly providing substantial assistance, or who conspires with the person who committed such an act of international terrorism,” if the act was

“committed, planned, or authorized” by a designated

foreign terrorist organization. 18 U.S.C. 2333(d)(2).

Like the primary-liability provision, the secondary-liability provision focuses on the “act of international terrorism” that injured the plaintiff. It requires that the

defendant aid and abet—i.e., knowingly provide substantial assistance to—the act of international terrorism, rather than the foreign terrorist organization itself

or its activities more generally. Thus, a defendant’s

knowing provision of “generalized aid” to a foreign terrorist organization is on its own insufficient to satisfy

the statute, Twitter Br. 31; see Google/Facebook Br. 2126, at least where there is no substantial causal link between the aid and the act of terrorism.

Plaintiffs contend that Section 2333(d)(2) “forbids

aiding and abetting certain persons, not aiding and

abetting certain acts.” Br. in Opp. 22. That is incorrect.

The statute makes civilly liable one who “aids and abets,

by knowingly providing substantial assistance, or who

conspires with the person who committed such an act of

international terrorism.” 18 U.S.C. 2333(d)(2) (emphasis added). The phrase “the person” is the object of

“conspires with,” not “aids and abets.” See Facebook/Google Br. 24-25. Thus, a defendant may be secondarily liable under the ATA where he (1) aids and

abets the terrorist attack in question, or (2) conspires

with the person who commits the attack with regard to

its commission.

The plain meanings of the words “aid and abet” and

“conspire” confirm that result. The couplet “aid and

abet” is generally defined in terms of specific acts, not

people, and conspiracy is defined as an agreement with

other persons to commit an unlawful act. See Black’s

Law Dictionary at 84 (“aid and abet”: “To assist or facilitate the commission of a crime, or to promote its accomplishment”); id. at 376 (“conspire”: “To engage in

conspiracy; to join in a conspiracy”); id. at 374 (“conspiracy”: An agreement by two or more persons to commit an unlawful act, coupled with an intent to achieve

the agreement’s objection, and (in most states) action or

conduct that furthers the agreement; a combination for

an unlawful purpose”).

In addition, Section 2333(d)(2) differs markedly from

the criminal material-support statute, 18 U.S.C. 2339B.

Section 2339B makes it a crime to “knowingly provide[]

material support or resources to a foreign terrorist organization,” without requiring a nexus to any particular terrorist act. Ibid. (emphasis added). Had Congress

envisioned a similar standard in Section 2333(d)(2), it

most likely would have used similar language.

B. A Plaintiff Need Not Necessarily Show That The Defendant Knew About Or Provided Aid Specific To The

Particular Terrorist Attack That Injured The Victim

Although Section 2333(d)(2) requires that the defendant “aid[] and abet[], by knowingly providing substantial assistance” to a particular terrorist act, it does

not necessarily require the plaintiff to show that the defendant knew about or provided aid specific to the particular terrorist attack in question. But see, e.g., Twitter Br. 37 (stating that plaintiffs must have plausibly alleged “at a minimum, that Defendants must have known

both of specific accounts that substantially assisted the

Reina attack and that not blocking those accounts would

substantially assist such an attack”). Rather, JASTA

specifically invokes Halberstam as the “proper legal

framework for how [secondary] liability should function

in th[is] context.” 18 U.S.C. 2333 note. And Halberstam

explained that Hamilton was liable for each of Welch’s

burglaries—and the murder he committed during one

of them—even though Hamilton did not “specifically”

know that the crimes Welch was committing were burglaries, and she may not have known of the particular

criminal episode during which he committed murder.

705 F.2d at 488. Similarly, there was no suggestion in

Halberstam that Hamilton provided her post-burglary

services to the particular crime that resulted in the

murder. For aiding-and-abetting liability, it was sufficient that Hamilton provided her substantial aid to a series of crimes committed by Welch with the knowledge

that “he was involved in some type of personal property

crime at night—whether as a fence, burglar, or armed

robber made no difference.” Ibid.; see id. at 484-485.

Of course, whether a secondary defendant’s actions

could reasonably be considered to knowingly and

substantially assist the act of international terrorism

that caused the plaintiffs’ injury in the absence of specific knowledge or particularized support will depend on

the facts of the case. In some circumstances—such as

the direct channeling of substantial funds or other fungible resources to a foreign terrorist organization or its

close affiliates with a knowing acquiescence in their potential use—a secondary defendant’s contributions may

have a sufficient nexus to a terrorist act, even if the defendant has no advance knowledge of, and does not provide support specifically directed to, the particular act.

See, e.g., Atchley, 22 F.4th at 227 (holding that a defendant could be held secondarily liable for “financially fortifying” entities known to be affiliated with foreign terrorist organizations through atypical transactions because such actions would foreseeably result in acts of

terrorism). As discussed above, however, plaintiffs’ allegations in this case do not meet that standard, because

plaintiffs primarily fault defendants for their inaction

and do not allege, inter alia, that defendants provided

atypical services or bent their usual policies so to support ISIS’s terrorist attacks, that they intended to further ISIS’s terrorist acts, or that they had anything

more than an arms-length transactional relationship

with ISIS.

CONCLUSION

The judgment of the court of appeals should be reversed.

Respectfully submitted.

BRIAN H. FLETCHER

Acting Solicitor General

MICHAEL D. GRANSTON

Deputy Assistant Attorney

General

EDWIN S. KNEEDLER

Deputy Solicitor General

ERICA L. ROSS

Assistant to the Solicitor

General

SHARON SWINGLE

JENNIFER L. UTRECHT

Attorneys

Department of Justice

Washington, D.C. 20530-0001

SupremeCtBriefs@usdoj.gov

(202) 514-2217

DECEMBER 2022

This is a copy of a public record, reproduced as it was published. It is not legal advice, and it may not be the version a court would rely on. Check the official source before you cite it.