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

No. 21-1496

IN THE

Supreme Court of the United States

————

TWITTER, INC.,

v.

Petitioner,

MEHIER TAAMNEH, et al.,

Respondents.

————

On Writ of Certiorari to the

United States Court of Appeals

for the Ninth Circuit

————

AMICUS BRIEF FOR

SENATOR CHARLES E. GRASSLEY

IN SUPPORT OF RESPONDENTS

————

MICHAEL A. PETRINO

Counsel of Record

JONATHAN E. MISSNER

STEIN MITCHELL BEATO &

MISSNER LLP

901 Fifteenth St., NW,

Suite 700

Washington, D.C. 20005

(202) 737-7777

mpetrino@steinmitchell.com

January 18, 2023

Counsel for Amicus Curiae

WILSON-EPES PRINTING CO., INC. – (202) 789-0096 – WASHINGTON, D.C. 20002

TABLE OF CONTENTS

Page

TABLE OF AUTHORITIES ................................

ii

INTEREST OF THE AMICUS ...........................

1

SUMMARY OF ARGUMENT .............................

2

ARGUMENT ........................................................

5

I. JASTA’s Text Imposes Civil Liability on

Persons and Entities That Knowingly

Provide Substantial Assistance to

Terrorists and Their Agents .....................

5

II. American

Counterterrorism

Policy

Supports Liability for Persons and

Entities That Knowingly Provide

Services to Terrorists and Their Agents ...

16

III. This Court Should Affirm the Judgment

Below .........................................................

24

CONCLUSION ....................................................

30

(i)

ii

TABLE OF AUTHORITIES

CASES

Page(s)

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

549 F.3d 685 (7th Cir. 2008) ................. 6, 14, 27

Bostock v. Clayton County,

140 S. Ct. 1731 (2020) ...............................

13

Central Bank of Denver v. First Interstate

Bank of Denver,

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

6

Gonzalez v. Google,

No. 21-1333 (U.S.) .....................................

2

Halberstam v. Welch,

705 F.2d 472

(D.C. Cir. 1983) ............ 4, 7-10, 12-13, 23-25, 28

Holder v. Humanitarian Law Project,

561 U.S. 1 (2010) ....................... 13-14, 20-23, 27

Kaplan v. Lebanese Canadian Bank, SAL,

999 F.3d 842 (2d Cir. 2021) ......................

27

Kilburn v. Socialist People’s Libyan Arab

Jamahiriya,

376 F.3d 1123 (D.C. Cir. 2004) .................

14

King v. Burwell,

576 U.S. 473 (2015) ...................................

29

Linde v. Arab Bank, PLC,

882 F.3d 314 (2d Cir. 2018) ...................... 26-27

Merrill Lynch, Pierce, Fenner & Smith Inc.

v. Dabit,

547 U.S. 71 (2006) .....................................

29

Rothstein v. UBS AG,

708 F.3d 82 (2d Cir. 2013) .........................

6

iii

TABLE OF AUTHORITIES—Continued

Page(s)

Sutton v. United Air Lines, Inc.,

527 U.S. 471 (1999) ...................................

29

Taamneh v. Twitter, Inc.,

No. 18-17192 (9th Cir. 2021) ........... 5, 24-25, 30

CONSTITUTION

U.S. Const. amend. I ....................................

20

STATUTES

1 U.S.C. § 1 ...................................................

24

8 U.S.C. § 1189(a)(1)(C)................................

20

18 U.S.C. § 2339A(a) ....................................

4

18 U.S.C. § 2339A(b)(1) ................................

15

1, 8,

18 U.S.C. § 2339B ......................................... 4, 13

Anti-Terrorism Act of 1992, 18 U.S.C.

§§ 2331 et seq....................... 1, 3-6, 13, 16-19, 22

18 U.S.C. § 2333 ........................................

6

18 U.S.C. § 2333(a) ...................................

5

18 U.S.C. § 2333(d)(1) ...............................

24

18 U.S.C. § 2333(d)(2) ............................. 4, 6, 11

Anti-Terrorism Clarification Act of 2018,

Pub. L. 115-253 (2018) .............................. 1, 19

Antiterrorism and Effective Death Penalty

Act of 1996, Pub. L. No. 104-132,

§ 301(a)(7), 110 Stat. 1247 ............. 19-21, 23, 29

iv

TABLE OF AUTHORITIES—Continued

Page(s)

Communications Decency Act of 1996,

47 U.S.C. § 230 ..........................................

2

Justice Against Sponsors of Terrorism Act,

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

(2016) ..............1, 3-8, 10-13, 18-19, 22-26, 28-29

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

7

§ 2(a)(5), 130 Stat. 852 .............................. 4, 7-8

§ 2(a)(6), 130 Stat. 852 .......................... 7, 11, 28

§ 2(a)(7), 130 Stat. 852 .............................. 11, 28

§ 2(b), 130 Stat. 853 .......................... 4, 7, 11, 28

Promoting Security and Justice for Victims

of Terrorism Act of 2019, Pub. L. 116-94

(2019) ......................................................... 1, 19

Pub. L. No. 110-325 (2009) ...........................

29

COURT FILINGS

Oral Arg. Tr., Nos. 08-1498, 09-89, Holder

v. Humanitarian Law Project (Feb. 23,

2010) ..........................................................

18

OTHER AUTHORITIES

136 Cong. Rec. S7592 (daily ed. Apr. 19,

1990) .......................................................... 16, 19

136 Cong. Rec. S7593–94 (daily ed. Apr. 19,

1990) ..........................................................

16

136 Cong. Rec. at S14283-84 (daily ed. Oct.

1, 1990) ......................................................

17

v

TABLE OF AUTHORITIES—Continued

Page(s)

137 Cong. Rec. S8143 (daily ed. Apr. 16,

1991) .......................................................... 17, 19

138 Cong. Rec. S33629 (daily ed. Oct. 7,

1992) ..........................................................

18

160 Cong. Rec. S6657-01, S6659 (daily ed.

Dec. 11, 2014) ............................................

18

H.R. Rep. No. 102-105 (1992) .......................

17

H.R. Rep. No. 104-383 (1995) .......................

18

H.R. Rep. No. 115-858 (2018) .......................

22

S. Rep. No. 102-342 (1992) ........................ 5, 18-19

Veto Message from the President-S.2040

(Sept. 23, 2016), available at https://

obamawhitehouse.archives.gov/the-pressoffice/2016/09/23/veto-message-presidents2040..........................................................

8

INTEREST OF AMICUS CURIAE1

Senator Grassley is committed to disrupting terrorist

financing, ensuring justice for American victims of

terrorism, and maintaining the carefully crafted

national security architecture Congress developed

over the past 25 years in close consultation with the

Executive Branch.

He is the original sponsor of the Anti-Terrorism Act

1990 (“ATA”), Pub. L. No. 101-519, repealed for

technical reasons and reenacted in 1992 at Pub. L.

102–572 (now codified at 18 U.S.C. §§ 2331-2239D). He

has also sponsored or co-sponsored multiple amendments

to the ATA prompted by court decisions that erroneously restricted the ATA’s scope. These include the

Justice Against Sponsors of Terrorism Act (“JASTA”),

the Anti-Terrorism Clarification Act of 2018, and

the Promoting Security and Justice for Victims of

Terrorism Act of 2019, which further strengthened the

ATA and clarified Congress’s intent in response to

lower court rulings restricting its scope.

He therefore has significant knowledge of Congress’s

intent and knows that civil liability plays an important

role in deterring third parties from providing essential

services, including communications equipment, to

terrorists. See 18 U.S.C. § 2339A(b)(1).

He also writes as a representative of his, and

many others’, constituents. Hundreds of Americans

are currently plaintiffs in lawsuits under the ATA,

1

Counsel of record for all parties consented in writing to this

filing. Amici certify that no party or party’s counsel authored this

brief in whole or in part and that no party or party’s counsel made

a monetary contribution intended to fund the preparation or

submission of this brief.

2

including its aiding-and-abetting cause of action,

which provides an especially powerful remedy to U.S.

nationals killed or injured by acts of international

terrorism that were committed, planned, or authorized by designated foreign terrorist organizations

(“FTOs”). These plaintiffs include veterans who were

grievously injured and Gold Star families whose loved

ones were killed in Iraq and Afghanistan while serving

our nation, the victims of the September 11th attacks,

Americans who were tortured or killed by ISIS in

Syria, and many others who also deserve the

opportunity to have their cases decided on the merits.

The companion case of Gonzalez v. Google, No. 211333, presents weighty questions about whether

Section 230 of the Communications Decency Act

should continue to shield social media companies and

other internet providers from liability for the

consequences of third-party content. That case

presents a fundamentally different question for this

Court and therefore Senator Grassley takes no

position here on the proper scope of Section 230. He

also takes no position on the ultimate determination

of liability. He only submits this brief to defend the

plain meaning of statutes enacted by Congress.

SUMMARY OF ARGUMENT

This Court should hold that civil liability for aiding

and abetting does not require that a defendant knowingly provide substantial assistance to the specific

terrorist attack that injured a plaintiff. This is consistent with the plain text of the statute and with

Congress’s intent. Anything less would immunize even

a defendant who knowingly donated a billion dollars

to ISIS or al-Qaeda as long as the funds were not

earmarked for, or traceable to, a particular attack.

Such a result would be the very opposite of what

3

Congress intended when it enacted JASTA and is

inconsistent with the text of the statute.

Instead, liability is available against persons and

entities that knowingly provide substantial assistance

to terrorists and their agents, from which acts of

international terrorism are a reasonably foreseeable

risk. This result is compelled by the ATA’s plain text

and context. Furthermore, the ATA contains no exception for “ordinary businesses providing widely available

goods or services,” Pet. Br. 2. If those goods or services

are knowingly provided to terrorists and a jury

determines they are substantial, then it violates the

plain text of the ATA. Inferring such an exception to

the ATA is inconsistent with the text of the statute and

would compromise important cases involving not only

social media but also terror financing. Under the ATA,

the only way to determine the culpability of the

defendant’s assistance is, as JASTA requires, to permit a

jury to decide whether that assistance was provided

“knowingly,” and whether it was “substantial”—an

inquiry that permits the jury to weigh the parties’

assertions and evidence. In support of this contention,

amicus stresses three points.

First, the plain text of the ATA’s aiding-andabetting provision, created by JASTA in 2016, makes

clear the defendants are liable if they knowingly

provided substantial services to terrorist organizations and their agents when those organizations

injured or killed Americans. Mindful of this Court’s

admonitions that Congress should speak clearly, the

legislature did so here, unequivocally articulating

that it was providing American victims of terrorism

with “the broadest possible basis, consistent with the

Constitution of the United States, to seek relief against

persons, entities, and foreign countries, wherever acting

4

and wherever they may be found, that have provided

material support, directly or indirectly, to foreign

organizations or persons that engage in terrorist

activities against the United States.” JASTA § 2(b).

JASTA thus imposes secondary liability on “any

person who aids and abets, by knowingly providing

substantial assistance.” 18 U.S.C. § 2333(d)(2). There

is no exception for particular types of assistance;

the only requirement is that the assistance be

“substantial”—a fact-intensive inquiry governed by

the D.C. Circuit’s opinion in Halberstam v. Welch, 705

F.2d 472 (D.C. Cir. 1983), which Congress found

“provides the proper legal framework” for liability

under the statute. See JASTA § 2(a)(5). Under

Halberstam, even a “passive” contributor, whose “acts

were neutral standing alone,” can be held liable for

violent acts that were “a natural and foreseeable

consequence of the activity” they assisted. 705 F.2d at

474, 488.

Second, the ATA and JASTA are part of a broader

counterterrorism toolbox that includes criminal liability, sanctions, diplomatic efforts, and the use of force.

These counterterrorism policies rest on the axiom that

terrorists, and especially designated FTOs, are so dangerous that providing any material support to them

necessarily supports their violent activities. Congress

has long sought to prevent terrorists from accessing

resources they can use to harm our national interests

and our citizens, and so it has imposed sweeping criminal liability on those that provide any material support

to terrorists, and especially FTOs. See 18 U.S.C.

§§ 2339A(a), 2339B. To supplement the criminal provisions, Congress added the civil provision premised on

the same understanding of the danger posed by

supporting terrorists. Reading these provisions as a

5

cohesive whole, the Court should hold that any

company that knowingly provides substantial material

support to terrorists or their agents can be held liable

as an aider and abettor under JASTA.

Third, this Court should affirm the Ninth Circuit’s

decision insofar as the court of appeals held that the

Taamneh plaintiffs have stated a viable claim for

aiding and abetting under JASTA. In most respects

(save a few, addressed in detail in Part III, infra), the

Ninth Circuit stated the law correctly, and it reached

the right result.

ARGUMENT

I. JASTA’s Text Imposes Civil Liability on

Persons and Entities That Knowingly

Provide

Substantial

Assistance

to

Terrorists and Their Agents

1. Since 1992, the ATA has empowered “[a]ny

national of the United States injured in his or her

person, property, or business by reason of an act of

international terrorism, or his or her estate, survivors,

or heirs,” to sue and “recover threefold the damages he

or she sustains and the cost of the suit, including

attorney’s fees.” 18 U.S.C. § 2333(a).

Congress was clear when it enacted the ATA that it

wanted to reach not only suicide bombers and triggermen (whom Congress understood are usually dead,

hiding, or imprisoned after an attack, not to mention

judgment-proof), but also the individuals and entities

that enabled those terrorists—including especially

financial supporters and facilitators of terrorism, who

provide fungible resources that terrorists use to

execute and promote violence. See, e.g., S. Rep. No.

102-342, at 22 (1992) (explaining that the ATA seeks

to impose “liability at any point along the causal chain

6

of terrorism,” and thus “interrupt, or at least imperil,

the flow of money” to terrorists); see also Boim v. Holy

Land Found. for Relief & Dev., 549 F.3d 685, 690–91

(7th Cir. 2008) (“Damages are a less effective remedy

against terrorists and their organizations than against

their financial angels. Terrorist organizations have

been sued under section 2333 . . . but to collect a

damages judgment against such an organization, let

alone a judgment against the terrorists themselves (if

they can even be identified and thus sued), is . . . wellnigh impossible.”)

For years, however, judicial decisions inconsistently

interpreted the ATA; although some courts gave the

ATA its intended breadth, others resisted. The courts

that declined to read the ATA to reach aiding and

abetting often cited this Court’s decision in Central

Bank of Denver v. First Interstate Bank of Denver, 511

U.S. 164, 182 (1994), which held that “when Congress

enacts a statute under which a person may sue and

recover damages from a private defendant for the

defendant’s violation of some statutory norm, there is

no general presumption that the plaintiff may also sue

aiders and abettors.” These courts reasoned that

under this Court’s precedents, it would be improper to

read a cause of action for aiding and abetting into the

statute absent clear direction from Congress. See, e.g.,

Rothstein v. UBS AG, 708 F.3d 82, 97-98 (2d Cir. 2013).

Congress responded by enacting JASTA in 2016,

providing that when a U.S. national is injured by an

act of international terrorism that was committed,

planned, or authorized by a designated FTO, “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).

7

The codified findings accompanying JASTA are

instructive. They explain that “[i]t is necessary to

recognize the substantive causes of action for aiding

and abetting and conspiracy liability.” JASTA § 2(a)(4).

They provide that the D.C. Circuit’s decision in

Halberstam, “which has been widely recognized as the

leading case regarding Federal civil aiding and abetting and conspiracy liability, including by the Supreme

Court of the United States, provides the proper legal

framework for how such liability should function.” Id.

§ 2(a)(5). And they explain that those who:

knowingly or recklessly contribute material

support or resources, directly or indirectly, to

persons or organizations that pose a significant risk of committing acts of terrorism

that threaten the security of nationals of

the United States or the national security,

foreign policy, or economy of the United

States . . . should reasonably anticipate being

brought to court in the United States to

answer for such activities.

Id. § 2(a)(6).

JASTA also has a codified purpose section, which

explains that its purpose “is to provide civil litigants

with the broadest possible basis, consistent with

the Constitution of the United States, to seek relief

against” anybody, including “entities,” “wherever acting

and wherever they may be found, that have provided

material support, directly or indirectly, to foreign organizations or persons that engage in terrorist activities

against the United States.” JASTA § 2(b). “Material

support” is a statutory term of art that includes “any

property, tangible or intangible, or service,” including

“currency or monetary instruments or financial

8

securities, financial services,” and “communications

equipment,” among others. 18 U.S.C. § 2339A(b)(1).

JASTA was enacted with overwhelming bipartisan

support. The bill was introduced in the Senate by a

bipartisan group of cosponsors, and it passed in both

the Senate and the House of Representatives by voice

vote. President Obama vetoed the statute, but not

because of any controversy relating to the secondary

liability provisions; instead, the President objected to

a separate provision of JASTA relating to sovereign

immunity. See Veto Message from the President-S.2040,

(Sept. 23, 2016) available at https://obamawhitehouse.

archives.gov/the-press-office/2016/09/23/veto-messagepresident-s2040. Congress was unpersuaded: the Senate

overrode President Obama’s veto by a vote of 97 to 1;

the House overrode the veto by a vote of 348 to 77.

Robust bipartisan majorities in both houses of

Congress came together to override a Presidential veto

and provide American victims of terrorism with the

broadest possible basis to seek relief against those who

have provided support to terrorists. The resulting

statutory text, by its plain meaning, reaches any

person or entity that “knowingly” provides services to

terrorists directly or indirectly—as long as those

services are “substantial.”

Congress also directed courts to look to Halberstam

when applying the statute. JASTA § 2(a)(5). The

defendant in Halberstam was held liable for a murder

that she did not directly assist, or even know about.

Instead, she acted as a “banker, bookkeeper, recordkeeper, and secretary” to a burglary enterprise.

Halberstam, 705 F.2d at 487. The court described her

as a “passive but compliant partner” to the burglar, id.

at 474, and held that she could be liable even though

“her own acts were neutral standing alone” because,

9

when “evaluated in the context of the enterprise they

aided,” they were “important,” id. at 488.

With respect to the element of knowledge, Halberstam

held that it was enough that the defendant assisted

the burglar “with knowledge that he had engaged in

illegal acquisition of goods.” 705 F.2d at 488. Indeed,

to hold her liable for the murder, “it was not necessary

that [she] knew specifically that [he] was committing

burglaries. Rather, when she assisted him, it was

enough that she knew he was involved in some type of

personal property crime at night . . . because violence

and killing is a foreseeable risk in any of these

enterprises.” Id.

Halberstam then assessed whether that assistance

was “substantial” using a six-factor test including the

nature of the act encouraged (there, burglary), the

amount of assistance given by the defendant, the

defendant’s presence or absence at the time of the

tort, relation to the other tortfeasor, state of mind, and

the duration of assistance. Id. at 483-84. The court

stressed that when determining whether assistance is

substantial, courts should “apply a proportionality test

to particularly bad or opprobrious acts,” so that “a

defendant’s responsibility for the same amount of

assistance increases with the blameworthiness of the

tortious act or the seriousness of the foreseeable

consequences.” Id. at 484 n.13. Under this standard,

even “relatively trivial” assistance can count as

“substantial” when the underlying acts are bad

enough. Id.

Halberstam further explained that the principles

enunciated therein would have to “be adapted as new

cases test their usefulness in evaluating vicarious

liability.” 705 F.2d at 489. The court understood that

tort law constituted an important “supplement to the

10

criminal justice process and possibly [served] as a

deterrent to criminal activity,” as well as a way to

provide “economic justice for victims of crime.” Id.

From that language, Congress understood that courts

would read Halberstam in harmony with Congress’s

command to construe JASTA broadly.

The plain meaning of JASTA allows American

victims of terrorism to seek secondary liability against

persons or entities that knowingly provide substantial

services to terrorists and their agents. The element of

knowledge is satisfied if the defendant knows that it is

providing services to a terrorist enterprise—because

violence and killing are a natural and foreseeable

consequence of terrorist enterprises. Cf. Halberstam,

705 F.2d at 488 (“violence and killing is a foreseeable

risk in [stolen property] enterprises”). And the “substantial” element is satisfied if those services qualify

as such based on the six-factor test in Halberstam.

Substantial assistance, in whatever form, foreseeably

enables terrorists to carry out violent campaigns

against Americans, and Congress has sought for

decades to prevent terrorists from accessing exactly

that sort of support.

2. Petitioner argues that, because the injury giving

rise to JASTA aiding-and-abetting liability was caused

by an “act of international terrorism,” it follows that

the defendant must knowingly provide substantial

assistance to the specific terrorist attack that injured

the plaintiff. In effect, petitioner would require

plaintiffs to prove that defendants knew they were

assisting specific attacks, and to trace the assistance

they provided through to those attacks. That is

incorrect for four reasons.

First, if this Court accepts petitioner’s argument,

knowingly facilitating a billion-dollar payment to ISIS

11

would not be actionable unless the payment was

earmarked for a specific terrorist attack or funds from

that payment could be traced to the financing of that

attack. Such a result would be absurd and discredits

any rule that compels it.

Second, as the plaintiffs explain, the correct reading

of the statute is that JASTA reaches any person who

knowingly provides substantial assistance. The operative words in Section 2333(d)(2) do not include the

word “to.” When it enacted JASTA, Congress’s focus

was always on terrorist organizations and their agents,

as opposed to specific acts of terror. See, e.g., JASTA

§ 2(a)(6)-(7), (b) (describing, three separate times,

Congress’s intent to impose liability on anybody who

provides material support or resources to terrorists

and terrorist organizations, and not once suggesting a

requirement to trace that assistance to specific attacks).

Third, JASTA’s aiding and abetting theory of liability

does not require that the defendant’s substantial

assistance must be traceable to the act of international

terrorism that injured the plaintiff. Instead, Congress

understood that one of the primary ways terrorist

attacks are aided and abetted is when “persons,

entities, and foreign countries … provide[] material

support, directly or indirectly, to foreign organizations

or persons that engage in terrorist activities against

the United States. JASTA § 2(b). That is because these

organizations are adept at converting any form of

support—however innocuous—into fuel for further

violence. See Part II, infra. Indeed, because of the

fungibility of money, providing support to a terrorist

organization engaged in an ongoing campaign of

violence necessarily aids that violence because it

allows the organization to spend less on its other

activities, and more on its attacks.

12

Fourth, Halberstam refutes petitioner’s argument.

Contrary to petitioner’s assertion, Pet. Br. 24, the

“principal violation” in Halberstam was the “burglary

enterprise,” not the unplanned murder. 705 F.2d at

488. What is more, the defendant did not have to assist

burglaries directly, and the plaintiffs did not have to

trace the defendant’s assistance to the specific burglary that injured them. Thus, the D.C. Circuit

observed that Hamilton’s “own acts were neutral

standing alone”; that the amount of assistance she

gave was not “overwhelming as to any given burglary”;

and that she was “not present at the time of the

murder or even at the time of any burglary.” Id.

Indeed, “it was not necessary that Hamilton knew

specifically that Welch was committing burglaries” at

all—let alone that he was going to burglarize the

plaintiffs’ home. Instead, “it was enough that she knew

he was involved in some type of personal property

crime at night,” because “violence and killing [was] a

foreseeable risk” in any such enterprise. Id.

These holdings conclusively refute petitioner’s

suggestion that a defendant must have knowledge of

specific assistance provided to the commission of the

terrorist attack, or that the plaintiffs here must

somehow trace the assistance defendants provided to

the attack that injured them. Instead, the knowing

provision of substantial assistance to an ongoing

criminal enterprise has always been sufficient under

Halberstam to make the provider liable for the enterprise’s foreseeable torts. And that is why Congress

incorporated Halberstam into JASTA: to make it

crystal-clear that a defendant can be liable for

terrorist attacks when it knowingly provides substantial assistance to the terrorist organization or terrorist

enterprise that foreseeably committed those attacks.

13

3. Petitioner also asks the Court to fashion an

exception to the statute’s application that makes it

harder to state or prove a claim when the defendant

provides “generic, widely available services” like social

media services. Pet. i. Petitioner further contends that

liability hinges on whether knowing assistance to

terrorist organizations comes in the form of “ordinary

business” or even nominally “humanitarian” assistance. Pet. Br. 2. But these exceptions have no textual

basis, and Halberstam makes clear that conduct that

appears “neutral standing alone” may nevertheless be

culpable. 705 F.2d at 488.

What matters is not whether the support the

defendant provides is widely available or generic—but

instead whether the defendant provided that support

knowingly, and whether the support was substantial.

As this Court has explained, “[t]he people are entitled

to rely on the law as written, without fearing that

courts might disregard its plain terms based on some

extratextual consideration.” Bostock v. Clayton County,

140 S. Ct. 1731, 1749 (2020). Although Congress was

not specifically addressing material support provided

by social media services at the time it enacted JASTA,

that is of no relevance: “the fact that a statute has been

applied in situations not expressly anticipated by

Congress does not demonstrate ambiguity; instead, it

simply demonstrates the breadth of a legislative

command.” Id. (cleaned up).

The Court should also not accept petitioner’s suggestion that it add any heightened intent requirement

into JASTA based on the type of services at issue that

does not exist in the statute’s text. This argument is

similar to one the respondents made in Holder v.

Humanitarian Law Project, 561 U.S. 1 (2010), which

related to the meaning and constitutionality of

14

§ 2339B, the ATA’s criminal statute prohibiting the

provision

of

material

support

to

terrorist

organizations. The respondents there, who concededly

did not intend to advance terrorism, urged the Court

to read a specific intent requirement into the statute

when the material support at issue involved speech.

This Court rejected that argument, explaining that it

would make no sense to read the statute “as requiring

intent in some circumstances but not others,” when the

statutory text did not draw that distinction. Id. Here,

too, the statute does not impose different knowledge

standards based on the type of assistance at issue—

and this Court’s precedents foreclose adding

qualifications that Congress eschewed.

The easiest way to understand that petitioner’s

arguments are erroneous is to consider the most

fungible kind of support that Congress sought to

prevent: the transfer of cash to terrorists. One could

not imagine any commodity more generic, nor more

widely available; cash is a completely generic medium

of exchange, and there are trillions of dollars in

circulation. Once cash makes its way to a terrorist

organization, it is impossible to prove that a particular

note was used in connection with a particular terrorist

attack: “Money, after all, is fungible, and terrorist

organizations can hardly be counted on to keep careful

bookkeeping records.” Kilburn v. Socialist People’s

Libyan Arab Jamahiriya, 376 F.3d 1123, 1130 (D.C.

Cir. 2004); see also Boim, 549 F.3d at 698 (explaining

that defendants that make knowing contributions to

terrorist organizations are “jointly and severally

liable” even if “the death could not be traced to any of

the contributors” because “[a]nyone who knowingly

contributes to . . . an organization that he knows to

engage in terrorism is knowingly contributing to the

organization’s terrorist activities”).

15

It is also at least debatable whether the social media

services at issue here qualify as widely available, generic

services. Only a handful of companies have the power

to permit people instantly to broadcast messages to

billions of recipients. As the plaintiffs in this case

alleged, “social media platforms were essential to

ISIS’s growth and expansion.” Pet. App. 63a. Without

them, “ISIS would have no means of radicalizing

recruits beyond ISIS’s territorial borders,” but would

instead have been stuck with “short, low-quality

videos on websites that could handle only limited

traffic.” Id. at 63a-64a.

Instead, defendants’ platforms allowed ISIS to create

“its own media divisions and production companies

aimed at producing highly stylized, professionalquality propaganda,” and then spread those messages,

thus expanding its reach, and raising its profile

“beyond that of other terrorist groups.” Id. at 64a. That

these companies provided access to incredibly potent

communications tools indiscriminately during the

relevant period does not make those services

innocuous or harmless when terrorists use them to

fundraise, recruit, spread propaganda, and promote

violence. In other words, defendants are not merely

selling bread or dry-cleaning services; they allegedly

provided ISIS with access to a multi-billion-dollar

global communications infrastructure that has clear

and obvious utility to terrorists and their agents. That

the technology also has nonviolent applications is

irrelevant because the same is true of many other

kinds of material support identified by Congress as

problematic, e.g., cash. See 18 U.S.C. § 2339A(b)(1).

Under this Court’s precedents, the textual analysis

should end the inquiry. Congress spoke clearly,

commanding courts to construe the aiding-and-

16

abetting cause of action as broadly as the Constitution

permits. This Court should do so here and apply the

statute according to its terms.

II. American Counterterrorism Policy Supports

Liability for Persons or Entities That

Knowingly Provide Services to Terrorists

and Their Agents

The broader context of American counterterrorism

policy only confirms that companies that knowingly

provide substantial services to terrorists and their

agents are liable for aiding and abetting. This includes

both the ATA’s enactment history and its relationship

to criminal and administrative counterterrorism laws.

1. The ATA was enacted in response to a series of

horrific terrorist attacks on U.S. nationals abroad. In

1983, 241 Americans were murdered in a terrorist

bombing of the Marine barracks in Beirut. In 1985,

Palestine Liberation Organization (“PLO”) terrorists

hijacked a cruise ship in the Mediterranean and

murdered a wheelchair-bound American passenger,

Leon Klinghoffer, by shooting him in the head and

throwing his body into the sea. And just days before

Christmas in 1988, Libyan terrorist operatives planted

bombs on Pan Am Flight 103, which exploded over

Lockerbie, Scotland, killing hundreds of passengers

(including 190 American citizens) and 11 individuals

on the ground. See 136 Cong. Rec. S7593–94 (daily ed.

Apr. 19, 1990) (statement of Sen. Heflin).

On top of their grief, victims and their families

struggled to hold accountable the perpetrators of these

attacks and their enablers because of “reluctant courts

and numerous jurisdictional hurdles.” 136 Cong. Rec.

S7592 (daily ed. Apr. 19, 1990) (statement of Sen.

Grassley). For instance, in the Klinghoffer litigation,

17

the PLO raised jurisdictional defenses that the

plaintiffs managed to overcome “[o]nly by virtue of the

fact that the attack violated certain Admiralty laws

and that the [PLO] had assets and carried on activities

in New York.” H.R. Rep. No. 102-105, at 5 (1992). Even

then, Leon Klinghoffer’s family had to endure over a

decade of protracted litigation before the PLO agreed

to settle.

To confront the growing terrorist threat and provide

a forum for victims to have their day in court, Congress

undertook a careful examination of terrorist financing

networks to understand how best to disrupt terrorist

activity while providing justice and compensation to

victims. The result was the ATA’s civil liability provision, which “fill[ed] [a] gap” in U.S. counterterrorism

strategy by “establishing a civil counterpart” to

existing criminal penalties for international terrorism.

136 Cong. Rec. at S14283 (daily ed. Oct. 1, 1990)

(statement of Sen. Grassley); see 137 Cong. Rec. S8143

(daily ed. Apr. 16, 1991) (statement of Sen. Grassley)

(“The ATA removes the jurisdictional hurdles in the

courts confronting victims and it empowers victims

with all the weapons available in civil litigation.”).

When the ATA was reported to the Senate floor,

Senator Grassley, its champion and author, made

clear that civil liability would hold terrorists “accountable where it hurts them most, at their lifeline, their

funds.” 136 Cong. Rec. at S14284 (daily ed. Oct. 1,

1990) (statement of Sen. Grassley). Creating civil

liability for terrorists and their sponsors was no symbolic move. Rather, it reflected Congress’s recognition

that, to stop terrorist activity, the United States must

also cut perpetrators off from “the resource that keeps

18

them in business—their money.” 138 Cong. Rec.

S33629 (daily ed. Oct. 7, 1992) (statement of Sen.

Grassley).

Thus, the ATA’s civil liability provisions were

intended to deter those who may or may not share a

terrorist’s murderous purpose from providing contributions or services that foreseeably facilitate terrorist

activity. As Congress explained in enacting criminal

penalties for material support for terrorism, liability

reflects “the fungibility of financial resources and

other types of material support. Allowing an individual to supply funds, goods, or services” to terrorists

and their agents “frees an equal sum that can then be

spent on terrorist activities.” H.R. Rep. No. 104-383, at

81 (1995); see also Oral Arg. Tr. 39, Nos. 08-1498, 0989, Holder v. Humanitarian Law Project (Feb. 23,

2010) (“Congress reasonably decided that when you

help a . . . foreign terrorist organization’s legal activities,

you are also helping the foreign terrorist organization’s illegal activities”) (statement of then-Solicitor

General Kagan). As Senator Schumer noted in support

of JASTA when it was introduced, terrorists “need a

great deal of money and material support to carry out

attacks such as what occurred on 9/11.” 160 Cong. Rec.

S6657-01, S6659 (daily ed. Dec. 11, 2014) (statement

of Sen. Schumer). To deny terrorists access to funds—

and, importantly, to the financial services that enable

terrorists to make use of those funds—the Senate

Report accompanying the ATA expressly stated that

the statute imposed broad “liability at any point along

the causal chain of terrorism,” to “interrupt, or at least

imperil, the flow of money.” S. Rep. No. 102-342, at 22

(1992).

Congress also crafted a broad remedy to provide

justice to individual victims. As Senator Grassley

19

explained when introducing the ATA, “our civil justice

system provides little civil relief to the victims of

terrorism,” because “victims who turn to the common

law of tort or Federal statutes, find it virtually

impossible to pursue their claims because of reluctant

courts and numerous jurisdictional hurdles.” 136

Cong. Rec. S7592 (daily ed. Apr. 19, 1990) (statement

of Sen. Grassley). Congress therefore sought to

“codify” the principles that allowed Leon Klinghoffer’s

family to recover and “make the rights of American

victims definitive,” including for victims who, without

the ATA, would find jurisdictional hurdles insurmountable. 137 Cong. Rec. S8143 (daily ed. Apr. 16,

1991) (statement of Sen. Grassley). By enacting a

broad remedy, Congress intended to “open[] the

courthouse door to victims of international terrorism.”

S. Rep. No. 102-342, at 45 (1992).

As noted above, some previous judicial interpretations of the ATA have been inconsistent with the

intent of the statute. Accordingly, Congress repeatedly

amended the statute to strengthen it and reemphasize

that Congress explicitly means what the text says.

Most notably, Congress enacted JASTA, codifying an

action for aiding and abetting in 2016. Congress would

go on to enact the ATCA, as well as the PSJVTA, both

of which address judicial decisions improperly limiting

the scope of jurisdiction for terrorism torts.

2. The ATA and JASTA’s cause of action also work

alongside criminal and administrative efforts to deter

terrorism. American counterterrorism policy relies

substantially on the axiom that terrorist organizations

are so irredeemably violent that any support for them

inevitably advances that violence. That proposition is

codified in the Antiterrorism and Effective Death

Penalty Act of 1996 (“AEDPA”), Pub. L. No. 104-132,

20

§ 301(a)(7), which provides that “foreign organizations

that engage in terrorist activity are so tainted by their

criminal conduct that any contribution to such an

organization facilitates that conduct.” Indeed, to

designate an organization as an FTO, the Secretary of

State must determine that “the terrorist activity or

terrorism of the organization threatens the security of

United States nationals or the national security of the

United States.” 8 U.S.C. § 1189(a)(1)(C).

This Court considered the nature of terrorist organizations in Holder. There, humanitarian groups sought

to provide limited assistance to certain terrorist

organizations by training those organizations’ members

“how to use humanitarian and international law to

peacefully resolve disputes,” “petition various representative bodies such as the United Nations for relief,”

“present claims for tsunami-related aid to mediators

and international bodies,” participate in peace negotiations, and engage in political advocacy on behalf of

people living abroad. See Holder, 561 U.S. at 14-15. In

addition to unsuccessfully arguing that the statute

could not be interpreted to reach defendants that

lacked specific intent to further terrorism, see supra

p.13, the humanitarian groups argued that it would

violate the First Amendment to treat their speech as

criminal material support.

This Court addressed that constitutional argument

by applying strict scrutiny and found that the statute

survived it. The parties agreed, and the Court found,

that the government’s “interest in combating terrorism [was] an urgent objective of the highest order,”

and therefore a compelling interest for First Amendment purposes. Holder, 561 U.S. at 28. The humanitarian

groups argued, however, that the statute was not

21

narrowly tailored to that interest because “their

support will advance only the legitimate activities of

the designated terrorist organizations, not their

terrorism.” Id. at 28-29.

This Court rejected that argument. It observed that

“[w]hether foreign terrorist organizations meaningfully

segregate support of their legitimate activities from

support of terrorism is an empirical question,” which

Congress resolved in 1996 by making “specific findings,” including that “any contribution to [a terrorist

organization] facilitates” its terrorist conduct. Holder,

561 U.S. at 29 (quoting AEDPA § 301(a)(7)). Congress

also specifically “considered and rejected the view that

ostensibly peaceful aid would have no harmful effects”

when, during drafting, it “removed an exception” to

liability “for the provision of material support in the

form of ‘humanitarian assistance to persons not directly

involved in’ terrorist activity.” Id. (citation omitted).

Consistent with the requirements of strict scrutiny,

the Court did not just accept Congress’s conclusion,

but instead found it “justified.” Holder, 561 U.S. at 29.

The Court held that peaceful support still “further[s]

terrorism by foreign groups in multiple ways.” Id. at

30. Teaching terrorists how to request international

disaster relief would enable them to access funds. Id.

at 37. Those funds would “free[] up other resources

within the organization that may be put to violent

ends.” Id. at 30. After all, “[m]oney is fungible.” Id. at

31. Thus, when terrorist organizations raise funds for

“civilian and humanitarian ends,” that money is

often redirected “to fund the purchase of arms and

explosives.” Id. (quotation marks omitted). The Court

further found that support legitimizes terrorist organizations, enabling recruiting and fundraising. Id. at 30.

22

The Court also held that in this foreign affairs

context, it was appropriate to defer to Congress;

indeed, the Court believed that it was “vital in this

context not to substitute . . . our own evaluation of

evidence for a reasonable evaluation by the Legislative

Branch.” Holder, 561 U.S. at 34 (quotation marks

omitted). Accordingly, the Court determined that it

would be inappropriate to demand “hard proof—with

‘detail,’ ‘specific facts,’ and ‘specific evidence’—that

[the humanitarian groups’] proposed activities will

support terrorist attacks.” Id. Deeming this “a

dangerous requirement,” the Court concluded that the

law does not require the government to “conclusively

link all the pieces in the puzzle before we grant weight

to its empirical conclusions.” Id. at 34-35.

The Court thus accepted “the considered judgment

of Congress and the Executive that providing material

support to a designated foreign terrorist organization—

even seemingly benign support—bolsters the terrorist

activities of that organization.” Holder, 561 U.S. at 36.

It therefore upheld the material support statute

against a constitutional challenge.

The ATA, as amended by JASTA, is an important

complement to the material-support statutes. Both

laws are intentionally broad and designed to prevent

and deter third parties from knowingly providing

material support to terrorists. Both also rest on the

same empirical judgment that any person who knowingly provides such support is knowingly contributing

to the terrorists’ violent activities, and therefore a

proper target for liability. JASTA intentionally opens

the courthouse door to American victims of terrorism

where the material support to terrorists is substantial.

See H.R. Rep. No. 115-858, at 3 (2018) (“The ATA’s

civil liability provision is aimed at deterring support

23

for terrorism, buttressing the country’s counterterrorism initiatives, and providing justice for victims of

terrorist attacks.”).

The empirical principles underlying the criminal

material-support statutes also inform the scope of

liability under JASTA. That is because Halberstam

establishes that a defendant who knowingly assists an

illegal enterprise can be held liable for unlawful acts

that are a natural and foreseeable consequence of that

enterprise. See 705 F.2d at 488. The criminal materialsupport statutes, and this Court’s precedents interpreting them, help courts understand what consequences

are “foreseeable” when a defendant provides material

support to terrorists. Specifically, in Holder, this

Court held that it was “wholly foreseeable” that

terrorists could use peaceful dispute resolution skills

“as part of a broader strategy to promote terrorism,”

describing that possibility as “real, not remote.” 561

U.S. at 36-37. That is because it has been a known,

codified fact since at least 1996—embraced by this

Court by 2010—that any contribution to terrorists and

their agents furthers terrorism. See AEDPA § 301(a)(7);

Holder, 561 U.S. at 29. Accordingly, no company

familiar with U.S. law should be able to profess that

acts of terrorism were an unforeseeable risk of

knowing and substantial assistance to terrorists—

regardless of whether the assistance came in a

“routine” or “ordinary” form. That argument did not

work for humanitarian groups allegedly pursuing

peace, and it cannot work any better for corporations

seeking to conduct business.

24

III. This Court Should Affirm the Judgment

Below

In light of the foregoing principles, the portion of the

Ninth Circuit’s judgment holding that the Taamneh

plaintiffs stated a valid claim for aiding and abetting

should be affirmed. The court of appeals’ analysis—

which considers two separate complaints—broadly

tracks JASTA’s intent, with a few exceptions where

the court did not go far enough in recognizing the

breadth of JASTA’s cause of action.

First, the Ninth Circuit correctly concluded that the

organization ISIS, and not the specific shooter, was

the relevant “person” for purposes of the first element

of the Halberstam analysis. Pet. App. 49a. Under

JASTA, the word “person” takes the meaning given in

1 U.S.C. § 1, which includes, in addition to individuals,

“associations” and other entities, properly understood

to include organizations. See 18 U.S.C. § 2333(d)(1).

Thus, a “person” need not be a natural person—and an

attack committed by a terrorist organization suffices.

Second, the Ninth Circuit held that plaintiffs

plausibly alleged the “general awareness” element of

their claim—but the court phrased this element

somewhat imprecisely. As the court acknowledged

when it quoted Halberstam, this element requires the

defendant to be “generally aware of his role as part of

an overall illegal or tortious activity at the time that

he provides the assistance.” Pet. App. 48a (quoting

Halberstam, 705 F.2d at 477); see also Pet. App. 61a.

In Halberstam itself, the defendant was aware that

she was playing a role only in the burglary enterprise.

See 705 F.2d at 488. She was liable for the unplanned

murder not because she played any role in it, but

because “it was a natural and foreseeable consequence

25

of the activity” she aided (i.e., the burglary enterprise).

Id.

In this case, the Ninth Circuit held that the element

was satisfied by a showing that the defendant “was

generally aware of its role in ISIS’s terrorist activities

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

50a; see also id. at 62a (holding that the defendants

“after years of media coverage and legal and government pressure concerning ISIS’s use of their platforms,

were generally aware they were playing an important

role in ISIS’s terrorism enterprise by providing access

to their platforms and not taking aggressive measures

to restrict ISIS-affiliated content”).

While showing that a defendant knew that it was

playing a role in terrorist activities would certainly be

sufficient to satisfy JASTA’s scienter element, it is not

required. There are many “illegal or tortious” activities

that can foreseeably lead to terrorism ranging from

money laundering and counterterrorism sanctions evasion to donating to terrorist organizations’ nominally

non-violent activities. To the extent this Court discusses

the general awareness element, it should reflect

Halberstam’s precise articulation of the governing

standard to make it clear that the overall illegal or

tortious activity in which the defendant plays a role

need not itself be acts of terrorism (let alone the

specific act that injured the plaintiff), as long as

terrorism is a foreseeable risk of that illegal or tortious

activity.2

The Court should also reject petitioner’s attempt to

characterize Taamneh as holding that petitioner merely failed to

do enough to stop ISIS from using its platform. As the Ninth

Circuit clearly explained, petitioner allegedly did more than that;

it also proactively provided access to the platform despite

knowledge that ISIS was using it. Pet. App. 62a. Indeed, the court

2

26

The Ninth Circuit also correctly held that “the

allegation that Google knowingly gave ‘fungible

dollars to a terrorist organization’ plausibly alleges

that Google was aware of the role it played in activities

that may be dangerous to human life.” Pet. App. 51a

(quotation marks omitted). As explained in Part II

supra, Congress has long recognized that money is

fungible, such that providing financial assistance to

terrorist organizations foreseeably enables them to

carry out acts of violence (either using those funds or

using other funds that are freed up as a result of the

financial assistance). Although it will seldom be

possible to trace funds through a terrorist organization, it is a well-established empirical reality that the

provision of fungible resources to terrorists foreseeably causes terrorist violence. Accordingly, courts

should hold that the knowing provision of such

resources can satisfy JASTA’s scienter element.

On the other hand, the Ninth Circuit was wrong to

suggest that “aiding and abetting an act of international terrorism requires more than the provision of

material support to a designated terrorist organization.”

Pet. App. 51a (quoting Linde v. Arab Bank, PLC, 882

F.3d 314, 329 (2d Cir. 2018)). The Second Circuit made

this statement in Linde but has since then explained

that the statement has been misconstrued. Thus, the

Second Circuit has clarified that:

Our statement that aiding-and-abetting liability

“requires more than the provision of material

support to a terrorist organization,” Linde,

noted plaintiffs’ allegation that despite being “aware of ISIS’s use

of their respective social media platforms for many years—

through media reports, statements from U.S. government

officials, and threatened lawsuits,” they have “refused to take

meaningful steps to prevent that use.” Id.

27

882 F.3d at 329 (emphasis added), does not

establish that material support to an FTO

is never sufficient for aiding-and-abetting

liability. Instead, that statement articulates

the principle that knowingly providing

material support to an FTO, without more,

does not as a matter of law satisfy the general

awareness element.

Kaplan v. Lebanese Canadian Bank, SAL, 999 F.3d

842, 860 (2d Cir. 2021) (emphasis added). That

clarification was clearly warranted because, where the

assistance is substantial, the knowing provision of

material support to a terrorist organization will almost

always qualify as aiding and abetting. For example,

the provision of substantial amounts of money to an

organization that a defendant knows to be a terrorist

organization qualifies because, for the reasons explained

above, it is eminently foreseeable that providing such

support will cause terrorist attacks. See, e.g., Holder,

561 U.S. at 36-37 (holding that it was “wholly foreseeable” that a terrorist organization could use any

contribution “as part of a broader strategy to promote

terrorism,” and that because “[m]oney is fungible,”

any “money a terrorist group . . . obtains . . . could be

redirected to funding the group’s violent activities”);

Boim, 549 F.3d at 698 (“Anyone who knowingly

contributes to . . . an organization that he knows to

engage in terrorism is knowingly contributing to the

organization’s terrorist activities.”). This Court should

affirm this Congressional finding.

With respect to the requirement that the defendant

“knowingly and substantially assist the principal

violation,” the Ninth Circuit held that the relevant

“principal violation” was ISIS’s overall terrorist campaign, not the specific attack that injured the plaintiff.

28

Pet. App. 54a; id. at 63a. For the reasons stated above,

this is, broadly-speaking, correct. Under Halberstam,

a defendant can be secondarily liable not only for the

specific acts it assisted, but also for any reasonably

foreseeable (tortious or illicit) acts done in connection

with the acts assisted. 705 F.2d at 488.

Petitioner takes issue with this holding, arguing

that liability should only be available if the defendant

aided the specific attack—and not an overall campaign

of terrorism or a particular terrorist organization.3 For

the reasons given above, this is incorrect and inconsistent with the plain language of the statute. Petitioner

(and the other defendants) fail to acknowledge JASTA’s

findings and purpose section, which makes clear that

Congress intended liability to reach those who “knowingly or recklessly contribute material support or

resources, directly or indirectly, to persons or organizations that pose a significant risk of committing acts

of terrorism.” JASTA § 2(a)(6) (emphasis added); id.

§ 2(a)(7) (explaining that JASTA creates “civil claims

against persons, entities, or countries that have

knowingly or recklessly provided material support or

resources, directly or indirectly, to the persons or

organizations responsible” for Americans’ injuries); id.

§ 2(b) (explaining that JASTA provides “civil litigants

with the broadest possible basis” to seek relief against

anyone that has “provided material support, directly

or indirectly, to foreign organizations or persons that

engage in terrorist activities against the United

States”). This Court has repeatedly recognized that

such codified findings and statements of purpose shed

important light on the meaning of statutes. See, e.g.,

Because terrorist organizations constitute a criminal

enterprise, knowingly providing substantial assistance to an FTO

or its agents satisfies this element.

3

29

King v. Burwell, 576 U.S. 473, 482 (2015); Sutton v.

United Air Lines, Inc., 527 U.S. 471, 484 (1999),

overturned on other grounds due to legislative action,

Pub. L. No. 110-325 (2009); Merrill Lynch, Pierce,

Fenner & Smith Inc. v. Dabit, 547 U.S. 71, 86 (2006).

Petitioner’s proposed reading would render JASTA’s

enforcement mechanism useless because in most cases

it is impossible to trace specific support to specific

attacks. Indeed, to the best of amicus’s knowledge, no

court has interpreted JASTA to require further tracing to a specific attack when, as here, the defendants

provided substantial assistance to terrorists or their

agents. That is because the provision of such support

is an unlawful activity that foreseeably risks terrorist

violence per se. See, e.g., AEDPA § 301(a)(7).

Limiting liability in this situation is also not necessary to avoid ensnaring innocent companies because

knowingly providing material support to a terrorist

organization is already a felony. There is nothing

innocent about a company that receives repeated

warnings from the government and news outlets and

continues to provide a platform to the world’s deadliest

terrorists. Such a company already faces criminal

liability; in that context, civil judgments present no

trap for the unwary.

Petitioner argues that the Ninth Circuit required

only that it was “generally aware that ISIS adherents

were somewhere among the billions using their ordinary services” and that Defendants’ efforts to remove

terrorist content were insufficient. Pet. Br. 2. If that

had been the Ninth Circuit’s holding, it would have

been erroneous, but this misstates the holding of that

court. JASTA is not a negligence statute. The Ninth

Circuit credited the plausibility of the plaintiffs’

allegations that the defendants chose not to remove

30

ISIS users, and multiple factors in the “substantial

assistance” inquiry weighed in favor of liability—

including the nature of the act assisted (terrorism), the

importance of the assistance provided (very important),

and the duration of the assistance (years, despite

multiple warnings from many authoritative sources).

Of course, discovery may show that during the

relevant period the defendants were merely negligent

or lacked the technological capacity to effectively

prevent ISIS users from using their platforms. But for

purposes of the pleading stage, the Ninth Circuit was

correct to hold that allegations of knowingly providing

substantial assistance to ISIS are enough for ISIS’s

victims to state a claim.

CONCLUSION

The judgment below should be affirmed insofar as it

holds that the Taamneh plaintiffs have stated a valid

aiding-and-abetting claim.

Respectfully submitted,

MICHAEL A. PETRINO

Counsel of Record

JONATHAN E. MISSNER

STEIN MITCHELL BEATO &

MISSNER LLP

901 Fifteenth St., NW,

Suite 700

Washington, D.C. 20005

(202) 737-7777

mpetrino@steinmitchell.com

January 18, 2023

Counsel for Amicus Curiae