United States Court of Appeals

For the First Circuit

No. 22-1823

ESTADOS UNIDOS MEXICANOS,

Plaintiff, Appellant,

v.

SMITH & WESSON BRANDS, INC.; BARRETT FIREARMS MANUFACTURING, 

INC.; BERETTA U.S.A. CORP.; GLOCK, INC.; STURM, RUGER & COMPANY, 

INC.; WITMER PUBLIC SAFETY GROUP, INC., d/b/a Interstate Arms; 

CENTURY INTERNATIONAL ARMS, INC.; BARETTA HOLDINGS SPA; GLOCK 

GES.M.B.H.; COLT'S MANUFACTURING COMPANY, LLC,

Defendants, Appellees.

APPEAL FROM THE UNITED STATES DISTRICT COURT

FOR THE DISTRICT OF MASSACHUSETTS

[Hon. F. Dennis Saylor, IV, U.S. District Judge]

Before

Kayatta, Gelpí, and Montecalvo,

Circuit Judges.

Steve D. Shadowen and Jonathan E. Lowy, with whom Richard M. 

Brunell, Nicholas W. Shadowen, Shadowen PLLC, and Global Action on 

Gun Violence were on brief, for appellant.

Sameer Advani, James C. Dugan, Gabrielle K. Antonello, 

Ferdinand G. Suba, Jr., Willkie Farr & Gallagher LLP, Zainab Ali, 

and Benita Yu on brief for Jorge Sánchez Cordero Dávila and Raúl 

Contreras Bustamante, amici curiae.

Thomas M. Sobol and Hagens Berman Sobol Shapiro LLP on brief 

for Scholars of International Law, amici curiae.

Lawson E. Fite, Michael B. Smith, and Marten Law LLP on brief 

for Gun Violence Prevention Groups, amici curiae.
Roberta L. Horton, Lucy S. McMillan, and Arnold & Porter Kaye 

Scholer LLP on brief for Mexican Activists, Scholars, and Victims, 

amici curiae.

Donna M. Evans, Julie G. Reiser, Molly J. Bowen, Zachary R. 

Glubiak, and Cohen Milstein Sellers & Toll PLLC on brief for Law 

Enforcement Officers, amici curiae.

Andrea Joy Campbell, Attorney General of Massachusetts, 

Elizabeth N. Dewar, State Solicitor, Rob Bonta, Attorney General 

of California, William Tong, Attorney General of Connecticut, 

Kathleen Jennings, Attorney General of Delaware, Brian L. Schwalb, 

Attorney General for the District of Columbia, Anne E. Lopez, 

Attorney General of Hawai'i, Kwame Raoul, Attorney General of 

Illinois, Anthony G. Brown, Attorney General of Maryland, Dana 

Nessel, Attorney General of Michigan, Keith Ellison, Attorney 

General of Minnesota, Matthew J. Platkin, Attorney General of New 

Jersey, Raúl Torrez, Attorney General of New Mexico, Letitia James, 

Attorney General of New York, Ellen F. Rosenblum, Attorney General 

of Oregon, Michelle A. Henry, Attorney General of Pennsylvania, 

Peter F. Neronha, Attorney General of Rhode Island, and Charity R. 

Clark, Attorney General of Vermont, on brief for Massachusetts, 

California, Connecticut, Delaware, the District of Columbia, 

Hawai'i, Illinois, Maryland, Michigan, Minnesota, New Jersey, New 

Mexico, New York, Oregon, Pennsylvania, Rhode Island, and Vermont, 

amici curiae.

Roberto J. Gonzalez, Jacob A. Braly, and Paul, Weiss, Rifkind, 

Wharton & Garrison LLP on brief for Latin American and Caribbean 

Nations and NGO, amici curiae.

Ellen V. Leonida, Matthew Borden, Kory J. DeClark, and 

Braunhagey & Borden LLP on brief for District Attorneys, amici 

curiae.

Edward V. Colbert III, Scott Harshbarger, and Casner & 

Edwards, LLP on brief for Professors of Transnational Litigation, 

amici curiae.

Noel J. Francisco, with whom Anthony J. Dick, Harry S. Graver, 

Andrew E. Lelling, Jones Day, James M. Campbell, Campbell Conroy 

& O'Neil, P.C., James W. Porter, II, Porter & Hassinger, P.C., 

Mark D. Sheridan, Squire Patton Boggs (US) LLP, Patricia A. 

Hartnett, Peter M. Durney, Smith Duggan Cornell & Gollub, 

Christopher Renzulli, Jeffrey Malsch, Renzulli Law Firm LLC, 

Jonathan I. Handler, Day Pitney LLP, James Vogts, Andrew A. 

Lothson, Swanson, Martin & Bell LLP, Nora R. Adukonis, S. Jan 

Hueber, Litchfield Cavo LLP, Joseph G. Yannetti, Morrison Mahoney 

LLP, Anthony M. Pisciotti, Danny C. Lallis, Ryan L. Erdreich, 

Pisciotti Lallis Erdreich, John G. O'Neill, Sugarman, Rogers, 

Barshak & Cohen, P.C., Michael L. Rice, Katie J. Colopy, and 

Harrison Law LLC were on brief, for appellees.

Peter M. Torstensen, Jr., Assistant Solicitor General, Austin 
Knudsen, Montana Attorney General, Christian B. Corrigan, 

Solicitor General, Brent Mead, Deputy Solicitor General, Tanner 

Baird, Solicitor's Fellow, Steve Marshall, Attorney General of 

Alabama, Treg Taylor, Attorney General of Alaska, Tim Griffin, 

Attorney General of Arkansas, Ashley Moody, Attorney General of 

Florida, Christopher M. Carr, Attorney General of Georgia, 

Theodore E. Rokita, Attorney General of Indiana, Brenna Bird, 

Attorney General of Iowa, Daniel Cameron, Attorney General of 

Kentucky, Jeff Landry, Attorney General of Louisiana, Lynn Fitch, 

Attorney General of Mississippi, Andrew Bailey, Attorney General 

of Missouri, John M. Formella, Attorney General of New Hampshire, 

Alan Wilson, Attorney General of South Carolina, Marty J. Jackley,

Attorney General of South Dakota, Ken Paxton, Attorney General of 

Texas, Sean D. Reyes, Attorney General of Utah, Jason Miyares, 

Attorney General of Virginia, Patrick Morrisey, Attorney General 

of West Virginia, and Bridget Hill, Attorney General of Wyoming, 

on brief for State of Montana and 19 Other States, amici curiae.

H. Christopher Bartolomucci, Kenneth A. Klukowski, and 

Schaerr Jaffe LLP on brief for U.S. Senator Ted Cruz, U.S. 

Representative Mike Johnson, and 37 other members of Congress, 

amici curiae.

Christopher A. Kenney, Kenney & Sams, P.C., and Paul B. 

Stephan on brief for National Shooting Sports Foundation, Inc., 

amicus curiae.

January 22, 2024
- 4 -

KAYATTA, Circuit Judge. The government of Mexico brings 

this lawsuit against seven U.S. gun manufacturers and one gun 

distributor.1 The district court dismissed Mexico's complaint 

because it concluded that Mexico's common law claims were barred 

by the Protection of Lawful Commerce in Arms Act (PLCAA). That 

act prohibits the bringing of certain types of lawsuits against 

manufacturers and sellers of firearms in federal and state courts. 

We agree that the PLCAA's limitations on the types of lawsuits 

that may be maintained in the United States apply to lawsuits

initiated by foreign governments for harm suffered outside the 

United States. However, we also hold that Mexico's complaint 

plausibly alleges a type of claim that is statutorily exempt from 

the PLCAA's general prohibition. We therefore reverse the district 

court's holding that the PLCAA bars Mexico's common law claims, 

and we remand for further proceedings. Our reasoning follows.

I.

"Because this appeal flows from the district court's 

order granting a motion to dismiss, we draw the relevant facts 

from the complaint, accepting all well-pleaded factual allegations 

1 Defendants are Smith & Wesson Brands, Inc.; Barrett 

Firearms Manufacturing, Inc.; Beretta U.S.A. Corp.; Century 

International Arms, Inc.; Colt's Manufacturing Company, LLC;

Glock, Inc.; and Sturm, Ruger & Co., Inc. and Witmer Public Safety 

Group, Inc., doing business as Interstate Arms. Mexico also 

initially named two foreign holding companies as defendants, but 

later voluntarily dismissed its claims against those companies.
- 5 -

as true." Foisie v. Worcester Polytechnic Inst., 967 F.3d 27, 32 

(1st Cir. 2020).

Mexico has strict gun laws that make it "virtually 

impossible" for criminals to obtain firearms legally sourced in 

the country. It has one gun store in the entire nation and issues 

fewer than fifty gun permits a year. Despite these strong domestic 

regulations, Mexico has the third-most gun-related deaths in the 

world. The number of gun-related homicides in Mexico grew from 

fewer than 2,500 in 2003 to approximately 23,000 in 2019. The 

percentage of homicides committed with a gun similarly rose from 

fifteen percent in 1997 to sixty-nine percent in 2021.

The increase in gun violence in Mexico correlates with 

the increase of gun production in the United States, beginning 

with the end of the United States' assault-weapon ban in 2004.2 

The complaint details a steady and growing stream of illegal gun 

trafficking from the United States into Mexico, motivated in large 

part by the demand of the Mexican drug cartels for military-style 

weapons. For example, Mexico claims that between seventy and 

ninety percent of the guns recovered at crime scenes in Mexico 

were trafficked into the country from the United States. 

Mexico's government has borne a variety of harms as a 

result of this gun-violence epidemic, including but not limited 

2 Violent Crime Control and Law Enforcement Act of 1994, Pub. 

L. No. 103-222, 108 Stat. 1796, 1996-1998(expired 2004).
- 6 -

to: costs of additional medical, mental-health, and other services 

for victims and their families; costs of increased law enforcement, 

including specialized training for military and police; costs of 

the increased burden on Mexico's judicial system; diminished 

property values; and decreased revenues from business investment 

and economic activity.

In an attempt to redress these harms, Mexico brought 

this lawsuit in federal district court in Massachusetts, seeking 

both damages and injunctive relief. Combined, defendants produce 

more than sixty-eight percent of the U.S. guns trafficked into 

Mexico, which comes out to between 342,000 and 597,000 guns each 

year. Mexico alleges that defendants know that their guns are 

trafficked into Mexico and make deliberate design, marketing, and 

distribution choices to retain and grow that illegal market and 

the substantial profits that it produces. 

Mexico alleges that one way defendants deliberately 

facilitate gun trafficking into Mexico is by designing their guns 

as military-style weapons, knowing that such weapons are 

particularly sought after by the drug cartels in Mexico. For 

instance, defendants make assault rifles with high rates of fire, 

low recoil, and the capacity to hold large amounts of ammunition. 

The guns can be easily converted into fully automatic weapons. 

Some of defendants' guns are "weapons of war," such as the "armorpenetrating" Barrett .50 caliber sniper rifle, which can be (and 
- 7 -

has been) used to take down aircrafts and armored vehicles. Such 

weapons are especially attractive to Mexican drug cartels, which

frequently engage in military-style combat against Mexican 

military and police personnel. Defendants also choose to forego 

safety features (such as allowing only recognized users to fire

the weapon) that might decrease the guns' attractiveness to 

wrongdoers without diminishing their utility for law-abiding 

citizens. Similarly, Mexico alleges that defendants intentionally 

design their guns to have easily removable serial numbers, making 

them much more attractive to criminals both in the United States 

and abroad.

Mexico alleges that defendants not only design their 

guns as military-grade weapons; they also market them as such. 

Defendants' marketing materials depict their weapons in use by or 

in proximity to military and law enforcement personnel and contain 

other references to military and law enforcement. Advertisements 

include statements like "authentic Military & Police . . . 

design," "battle proven," and "transforms the military platform to 

fit civilian precision shooters." Mexico alleges that defendants 

engage in these marketing techniques knowing that they are 

disproportionately likely to attract groups harboring militaristic 

ambitions, like the Mexican cartels.

Mexico also alleges that defendants' distribution system 

facilitates illegal trafficking to Mexico. Defendants generally 
- 8 -

use a three-tier distribution system. Manufacturers (most 

defendants) sell to distributors; distributors (one defendant) 

sell to dealers; and dealers sell to consumers. Guns flow from 

this distribution system into Mexico in multiple ways. The most 

common method of trafficking is through "straw sales" -- sales 

made to a buyer purchasing on behalf of somebody else who is not 

lawfully permitted to buy a gun. Often, straw sales occur in 

circumstances that clearly indicate to the dealer that the 

transaction is a straw sale and could be prevented if defendants 

required their dealers to be well-trained and follow the law.

Other types of transactions that pose a particularly 

high risk of trafficking include sales of multiple guns to the 

same buyer over a limited period of time; sales by "kitchen-table" 

dealers who deal online or in locations that make it easy to avoid 

regulations; and sales by non-licensed sellers at gun shows without 

background checks. In addition, many guns are stolen or simply 

"lost" from firearm companies' inventory, and frequently 

thereafter end up in Mexico. According to the complaint, some of 

these "lost" guns are actually sold off the books, with dealers 

choosing not to implement anti-theft measures to allow them to 

falsely claim the guns were stolen.

Mexico alleges that defendants are aware of these 

practices and the resulting trafficking of guns into Mexico, yet 

deliberately maintain a distribution system that facilitates
- 9 -

illegal sales, resisting calls for reform by the U.S. government 

and prominent gun industry insiders, among others. Not only that, 

but defendants are aware that specific distributor and dealer 

networks are disproportionately associated with gun trafficking 

into Mexico. Mexico alleges that defendants are on notice as to 

which dealers are responsible for the lion's share of gun 

trafficking. Mexico points to data collected by the U.S. Bureau 

of Alcohol, Tobacco, Firearms and Explosives (ATF) and a 2010 news 

article naming twelve dealers that sold the most guns recovered in 

Mexico. Despite having access to this information, defendants 

continue supplying guns to those same dealers.

Importantly, according to the complaint, the aspects of 

defendants' businesses that facilitate trafficking are not 

unfortunate and unintended byproducts of a lawful enterprise. 

Rather, they are the result of defendants' affirmative and 

deliberate efforts to create and maintain an illegal market for 

their weapons in Mexico. Says Mexico, supplying guns to the 

illegal market in Mexico is "a feature, not a bug," of defendants' 

businesses. And the motivation behind this feature is money. 

Mexico estimates that defendants collectively receive over 

$170 million a year from sales of guns trafficked into Mexico. As 

a result of the profit potential of the Mexican market, gun dealers 

along the border have proliferated while elsewhere in the nation 

their numbers have decreased. Gun dealers in border states now 
- 10 -

sell twice as many guns as dealers in other parts of the country. 

As stated succinctly by Mexico, defendants "are not accidental or 

unintentional players in this tragedy; they are deliberate and 

willing participants, reaping profits from the criminal market 

they knowingly supply -- heedless of the shattering consequences 

to [Mexico] and its citizens."

II.

Defendants filed multiple motions to dismiss Mexico's 

complaint. All defendants moved to dismiss for lack of Article III 

standing under Federal Rule of Civil Procedure 12(b)(1) and for 

failure to state a claim under Rule 12(b)(6). Some defendants 

also moved to dismiss for lack of personal jurisdiction under 

Rule 12(b)(2). The district court held that Mexico had Article III 

standing, but it dismissed two counts for failure to state a claim 

on which relief could be granted.3 It also found that litigation

of the remaining counts was barred by the PLCAA, which prohibits 

the filing of a "qualified civil liability action" -- defined as 

"a civil action or proceeding . . . against a manufacturer or 

seller of a qualified product . . . for damages . . . resulting 

from the criminal or unlawful misuse of a qualified product by the 

person or a third party" -- in "any Federal or State court." 

3 The two counts were state statutory claims under the 

Connecticut Unfair Trade Practices Act and the Massachusetts 

Consumer Protection Act, respectively. Mexico does not, on appeal,

challenge the dismissal of those counts.
- 11 -

15 U.S.C. §§ 7902(a), 7903(5)(A). It therefore dismissed the 

complaint without addressing the motions to dismiss for lack of

personal jurisdiction. Mexico timely appealed, raising multiple 

challenges to the district court's application of the PLCAA to 

this lawsuit.

III.

Mexico first contends that the PLCAA does not apply to 

lawsuits brought by foreign governments for harm suffered outside 

the United States. It raises three arguments in support of this 

contention: first, that applying the PLCAA to such a lawsuit is an 

impermissible extraterritorial application of the statute; second, 

that the PLCAA's substantive terms must be interpreted to have 

only domestic scope; and third, that principles of international 

comity support Mexico's reading of the statute. We address these 

arguments in turn, finding them ultimately unavailing.

A.

"Courts presume that federal statutes 'apply only within 

the territorial jurisdiction of the United States.'" WesternGeco 

LLC v. ION Geophysical Corp., 138 S. Ct. 2129, 2136 (2018) (quoting 

Foley Bros. v. Filardo, 336 U.S. 281, 285 (1949)). This rule, 

commonly called the presumption against extraterritoriality, is a 

"canon of construction" that guides our interpretation of federal 

statutes. Yegiazaryan v. Smagin, 599 U.S. 533, 541 (2023) (quoting 

Morrison v. Nat'l Austl. Bank Ltd., 561 U.S. 247, 255 (2010)). 
- 12 -

Under the presumption, we construe federal laws "to have only 

domestic application" unless we find "clearly expressed 

congressional intent to the contrary." Id. (quoting RJR Nabisco, 

Inc. v. European Cmty., 579 U.S. 325, 335 (2016)). The presumption 

"reflects concerns of international comity insofar as it 'serves 

to protect against unintended clashes between our laws and those 

of other nations which could result in international discord.'" 

Id. (quoting Kiobel v. Royal Dutch Petroleum Co., 569 U.S. 108, 

115 (2013)). And it also embodies "the commonsense notion that 

Congress generally legislates with domestic concerns in mind." 

Id. (quoting Smith v. United States, 507 U.S. 197, 204 n.5 (1993)).

A two-step framework applies to questions of 

extraterritoriality. RJR Nabisco, 579 U.S. at 337. "At the first 

step, we ask whether the presumption against extraterritoriality 

has been rebutted -- that is, whether the statute gives a clear, 

affirmative indication that it applies extraterritorially." Id. 

If so, then an extraterritorial application of the statute is 

permissible. Id. If not, we proceed to the second step and ask 

if the statute's application in the case at hand is truly 

extraterritorial or if, instead, "the case involves a domestic 

application of the statute." Id. 

The district court concluded that the PLCAA's 

prohibition of lawsuits by "any governmental entity" and various 

references to "foreign commerce" fell short of a clear expression 
- 13 -

of congressional intent that the statute applies

extraterritorially. It therefore held that the presumption 

against extraterritoriality had not been overcome at step one. 

Defendants do not object to this holding on appeal. Nor do we see 

any need to question it, given that we agree with the district 

court's conclusion at step two: that the application of the PLCAA 

in this case is permissibly domestic, not impermissibly 

extraterritorial.

Determining whether an application of a statute is 

domestic or extraterritorial requires us to 

look[] to the statute's "focus." If the 

conduct relevant to the statute's focus 

occurred in the United States, then the case 

involves a permissible domestic application 

even if other conduct occurred abroad; but if 

the conduct relevant to the focus occurred in 

a foreign country, then the case involves an 

impermissible extraterritorial application 

regardless of any other conduct that occurred 

in U.S. territory.

Id. "The ultimate question regarding permissible domestic 

application turns on the location of the conduct relevant to the 

focus." Abitron Austria GmbH v. Hetronic Int'l, Inc., 600 U.S. 

412, 422 (2023). We therefore first ascertain the focus of the 

PLCAA and then determine where the conduct relevant to that focus 

occurred. 

"The focus of a statute is the object of its solicitude, 

which can include the conduct it seeks to regulate, as well as the 
- 14 -

parties and interests it seeks to protect or vindicate." Id. at 

418 (internal quotation marks omitted) (quoting WesternGeco, 138 

S. Ct. at 2136). The "conduct" that the PLCAA "seeks to regulate" 

is the filing and adjudication of certain lawsuits in domestic 

courts. See 15 U.S.C. § 7901(b)(1), (4) (stated purposes include 

"prohibit[ing] causes of action" and "prevent[ing] the use of such 

lawsuits to impose unreasonable burdens on interstate and foreign 

commerce"). Its operative provision states that "[a] qualified 

civil liability action may not be brought in any Federal or State 

court," and that any such pending actions "shall be immediately 

dismissed by the court." Id. § 7902. That is the only "conduct" 

that the statute "regulate[s]."

The PLCAA is also explicit about "the parties and 

interests it seeks to protect." Its stated "purposes" are, among 

other things, "[t]o prohibit causes of action against 

manufacturers, distributors, dealers, and importers of 

firearms . . . for the harm solely caused by the criminal or 

unlawful misuse of firearm products," and "[t]o preserve a 

citizen's access to a supply of firearms and ammunition for all 

lawful purposes." Id. § 7901(b)(1), (2); see also id.

§ 7901(a)(5)–(8) (finding that the firearm industry should not be 

liable for third parties' unlawful acts and that lawsuits seeking 

to impose such liability abuse the legal system); id.

§ 7901(a)(1)-(2) (invoking the Second Amendment). In short, it 
- 15 -

seeks to protect (1) U.S. firearm companies and their interests in 

manufacturing, marketing, and selling guns to the public; and 

(2) U.S. citizens and their interests in having access to guns.

We therefore agree with the district court's conclusion 

that the PLCAA's focus is "regulat[ing] the types of claims that 

can be asserted against firearm manufacturers and sellers . . . to 

protect the interests of the United States firearms industry and 

the rights of gun owners." Estados Unidos Mexicanos v. Smith & 

Wesson Brands, Inc., 633 F. Supp. 3d 425, 444 (D. Mass. 2022). 

Mexico resists this conclusion by proposing a different 

focus of the PLCAA: "gun misuse and the resulting injury." It 

argues that the district court erred by looking only at the PLCAA's 

operative provision -- which prohibits "qualified civil liability 

action[s]," 15 U.S.C. § 7902 -- and not its definitions 

section -- which defines such actions as "civil action[s] or 

proceeding[s] or . . . administrative proceeding[s]" for harm 

"resulting from the criminal or unlawful misuse of a qualified 

product by the person or a third party," id. § 7903(5)(A).

We agree that statutory provisions do not exist "in a 

vacuum" and "must be assessed in concert with . . . other 

provisions." WesternGeco, 138 S. Ct. at 2137. In WesternGeco, 

for example, the Supreme Court determined that the focus of a 

statute providing a remedy for patent infringement was "the 

infringement." Id. (quoting 35 U.S.C. § 284). But because the 
- 16 -

statute identified several types of infringement, the Court looked 

to a separate provision to determine what "the infringement" was 

in the case at hand. Id. That provision "provide[d] that a 

company 'shall be liable as an infringer' if it 'supplies' certain 

components of a patented invention 'in or from the United States'

with the intent that they 'will be combined outside of the United

States in a manner that would infringe the patent if such 

combination occurred within the United States.'" Id. at 2137–38 

(quoting 35 U.S.C. § 271(f)(2)). From this definition, the Court 

gleaned that the regulated conduct -- that is, "the 

infringement" -- was "the domestic act of 'suppl[ying] in or from 

the United States.'" Id. at 2138 (alteration in original) (quoting 

35 U.S.C. § 271(f)(2)). So, because it was that domestic act "that 

infringed [the] patents," the "conduct . . . relevant to [the] 

focus clearly occurred in the United States." Id.

Mexico contends that we should follow what it sees as a 

similar approach: treat the command of section 7902(a) (precluding 

"qualified civil liability action[s]" in any U.S. court) as 

insufficient to determine the focus; look at the definition of 

"qualified civil liability action" in section 7903(5)(A) (as 

meaning suits against defendants for damages resulting from 

unlawful use of certain firearms); and then declare that the 

statute's focus is actually on certain elements of that definition 

(damages and misuse). 
- 17 -

But while WesternGeco makes clear that it is sometimes 

necessary to turn to a secondary provision to help give meaning to 

the statute's focus, it does not stand for the proposition that 

whenever a term is defined in a separate provision, all parts of 

that definition become the focus of the statute. In WesternGeco, 

the portion of the secondary provision on which the Court 

concentrated was the very "infringement" that was the focus of the 

primary provision. Other parts of the definition -- such as the 

requirement that the components be "especially made or especially 

adapted for use in the invention," id. at 2135 (quoting 35 U.S.C. 

§ 271(f)(2)) -- were not the statute's focus because they did not 

constitute the act of infringement, which was the focus of the 

primary provision. Here, "qualified civil liability action[s]"

are the focus and we look to section 7903(5)(A) simply to define

the scope of that term, not to find in the elements of that 

definition some other focus. 

To drive this point home, imagine a law stating that "a 

qualified shirt may not be worn in any Federal or State court" and 

defining "qualified shirt" as "a collarless shirt made from 

cotton." Under Mexico's logic, a focus of that statute would be 

the cotton industry. And therefore the law would not prohibit the 

wearing of collarless shirts made from cotton grown outside the 

United States. But no reasonable person would think that the 

statute would not apply with equal force regardless of the origin 
- 18 -

of the cotton in a court attendee's shirt. So too, here; Mexico 

cannot shift the focus of the PLCAA from "qualified civil liability 

action[s]" to something else merely because that term -- which 

Mexico concedes is the focus of the PLCAA's operative 

provision -- is defined in a separate provision.

At a more fundamental level, Mexico's argument that the 

statute's focus is "gun misuse and the resulting injury" has too 

little connection to the PLCAA's purpose or effect. While 

curtailing gun misuse is a laudable goal (and one that may be the 

focus of other statutes), it is not the goal of the PLCAA. That 

statute's purpose, and effect, is to insulate U.S. gun industry 

actors from certain types of lawsuits in domestic courts. And 

that conduct is inherently domestic.

Mexico also argues that to say that the focus of the 

PLCAA is on regulating the types of claims that can be brought 

against U.S. gun industry actors "is so broad as to be 

tautological" because "[a]ll statutes 'regulate the type' of 

activity to which they are directed, and all such 'regulat[ion]' 

by definition occurs in the United States -- in the U.S. Courts 

that apply the statutes." But this argument confuses the effect

of a regulation with its focus; not all statutes are directed 

toward regulating lawsuits in the way the PLCAA is. For example, 

the statute in WesternGeco in some sense "regulated" the conduct 

of U.S. courts by creating a cause of action that those courts can 
- 19 -

adjudicate. But the focus of that statute was clearly on 

regulating patent infringement, e.g., infringement said to occur 

by shipping components overseas for assembly. 138 S. Ct. at 2137–

38. Here, by contrast, the PLCAA seeks to regulate the lawsuits 

themselves. 

Having thus determined the PLCAA's focus, we find it 

evident that the conduct relevant to that focus occurs 

domestically. Both the conduct that the statute seeks to 

regulate -- the filing and adjudication of lawsuits -- as well as 

the conduct that it seeks to protect -- defendants' manufacturing, 

marketing, and selling of guns -- take place entirely within the 

United States.

Mexico argues finally, and mostly in passing, that 

defendants "engage in conduct in Mexico when they aid and abet 

trafficking guns into Mexico." The Supreme Court has held that 

"suppl[ying] in or from the United States" components of a patented 

invention with the intent that they be assembled abroad is a 

"domestic act." Id. (alteration in original). Mexico develops no 

reason why selling guns in the United States with the intent that 

they be resold to persons in Mexico should not similarly be 

considered a domestic act.

For all these reasons, the presumption against 

extraterritoriality does not bar application of the PLCAA to this 

case.
- 20 -

B.

We now turn to Mexico's argument that the PLCAA 

nonetheless by its terms does not apply to a lawsuit brought by a 

foreign government based on damages occurring outside the United 

States caused by misuse outside the United States. Recall that 

the PLCAA prohibits lawsuits "brought by any person" (including 

"any governmental entity") "against a manufacturer or seller of a

[firearm] . . . for damages . . . or other relief, resulting from 

the criminal or unlawful misuse of a [firearm] by the person or a 

third party." 15 U.S.C. § 7903(3), (5)(A). Mexico argues that 

(1) "criminal or unlawful misuse" means only misuse that occurs in 

the United States and is unlawful under U.S. law; 

(2) "damages . . . or other relief" covers only injury incurred in 

the United States; and (3) "any governmental entity" encompasses 

only domestic governmental entities.

The Supreme Court recently rejected a similar contention 

in Turkiye Halk Bankasi A.S. v. United States, which involved a 

section of the U.S. Criminal Code granting federal district courts 

exclusive jurisdiction over "all offenses against the laws of the 

United States." 598 U.S. 264, 268-69 (2023) (quoting 18 U.S.C. 

§ 3231). The defendant, a bank owned by the Turkish government, 

argued that because the statute "refers generically to 'all'

federal criminal offenses without specifically mentioning foreign 

states or their instrumentalities, . . . foreign states and their 
- 21 -

instrumentalities do not fall within [the statute's] scope." Id.

at 269. The Court observed that the "text as written" "plainly 

encompasses" the defendant's offenses. Id. It therefore 

"decline[d] to graft an atextual limitation onto [the statute's] 

broad jurisdictional grant over 'all offenses,'" or to "create a 

new clear-statement rule requiring Congress to 'clearly indicat[e] 

its intent' to include foreign states and their 

instrumentalities." Id.

Similarly, in Pfizer, Inc. v. Government of India, the 

Supreme Court considered a provision of the Clayton Act allowing 

"any person" injured by a violation of U.S. antitrust laws to sue 

in U.S. district court. 434 U.S. 308, 311-12 (1978) (quoting 15 

U.S.C. § 15(a)). The Court held that "any person" includes foreign 

governments, in part because that interpretation furthered the 

"two purposes" of the provision: "to deter violators and deprive 

them of 'the fruits of their illegality,' and 'to compensate 

victims of antitrust violations for their injuries.'" Id. at 314 

(quoting Ill. Brick Co. v. Illinois, 431 U.S. 720, 746 (1977)). 

The Court reasoned that "[t]o deny a foreign plaintiff injured by 

an antitrust violation the right to sue would defeat these 

purposes" because "[i]t would permit a price fixer or a monopolist 

to escape full liability for his illegal actions and would deny

compensation to certain of his victims, merely because he happens 

to deal with foreign customers." Id. at 314–15.
- 22 -

Taken together, Turkiye and Pfizer guide our approach to 

interpreting the PLCAA. Here, as in Turkiye, the "text as written" 

does not contain the exceptions Mexico proposes. Nothing in the 

text of the PLCAA limits its scope to misuse or injury that occurs 

in the United States, or to U.S. plaintiffs. And, as in Pfizer, 

the context and purpose of the PLCAA weigh against such a 

limitation. Congress quite clearly enacted the PLCAA to insulate 

the U.S. gun industry from certain lawsuits. See 15 U.S.C. 

§ 7901(a)(5)–(8); id. § 7901(b)(1), (4). Limiting that protection 

to lawsuits brought for harm occurring in the United States, 

thereby exposing the U.S. gun industry to identical lawsuits for 

harm suffered abroad, would run directly contrary to that purpose. 

We also think it unlikely that Congress intended to allow recovery 

for victims of gun violence occurring abroad but preclude that 

same recovery for victims of gun violence occurring within U.S. 

borders. 

Nevertheless, Mexico urges us to read into the PLCAA an 

implicit domestic restriction on the statute's scope. It likens 

this case to Small v. United States, which involved a statute 

criminalizing possession of a firearm by "any person . . . who has 

been convicted in any court of, a crime punishable by imprisonment 

for a term exceeding one year." 544 U.S. 385, 387 (2005) (quoting 

18 U.S.C. § 922(g)(1)). There the Supreme Court held that the 

phrase "convicted in any court" encompasses only domestic, not 
- 23 -

foreign, convictions. Id. But at the same time the Court made 

clear that its conclusion would be different "should statutory 

language, context, history, or purpose show the contrary." Id. at 

391. Finding "no convincing indication to the contrary" in the 

statute, the Court applied an assumption "similar" to the 

presumption against extraterritoriality because "Congress 

generally legislates with domestic concerns in mind." Id. at 388, 

391 (quoting Smith v. United States, 507 U.S. 197, 204 n.5 (1993)).

The holding in Small provides no succor to Mexico. As 

we have explained, the PLCAA was also undoubtedly enacted with 

domestic concerns in mind; i.e., the impact of certain types of 

lawsuits filed in domestic courts against domestic firearm 

companies. So prohibiting all such lawsuits regardless of who 

brings them perfectly aligns with that domestic concern. The fact 

that a statute is focused on domestic concerns (here, lawsuits in 

U.S. courts) does not mean that every term in the statute need be 

read as somehow domestically limited. See, e.g., Turkiye, 598 

U.S. at 269; Pfizer, 434 U.S. at 314–15. And that is especially 

so where, as here, limiting the statute in this way would run 

directly contrary to its stated purposes.

Mexico begs to differ. It points to four "clues" that 

the PLCAA does not apply to lawsuits arising out of the use of 

guns in violation of foreign laws. We address each in turn. 
- 24 -

First, Mexico points out that the definition of the term 

"seller" in the PLCAA explicitly includes "importer[s]" but does 

not explicitly mention "exporters." 15 U.S.C. § 7903(6)(A). 

Similarly, "importers," but not "exporters," are specifically 

identified as a category of business that the PLCAA seeks to 

protect. Id. § 7901(b)(1). Mexico argues that this "confirms" 

that Congress only intended the PLCAA to be domestic in scope. 

But this is too slender a reed on which to support the 

interpretation Mexico seeks to advance. Even assuming Congress 

intended to exclude from the PLCAA's coverage the export of guns 

(an issue we do not decide here), that does not alter our 

conclusion that Congress certainly intended to include all lawful 

domestic sales of guns -- even when those domestically sold guns 

end up causing harm abroad. There are plausible reasons why 

Congress might have wanted to protect domestic sellers more than 

exporters, including Congress's stated purpose of "preserv[ing] a 

citizen's access to a supply of firearms and ammunition for all 

lawful purposes." 15 U.S.C. § 7901(b)(2) (emphasis added). If a 

domestic seller goes out of business, that hampers U.S. citizens' 

access to guns more than if an exporter goes out of business. 

Thus, the lack of any express mention of "exporters" does not mean 

that the PLCAA does not apply to actions against domestic 

manufacturers and sellers for harm suffered in another country.
- 25 -

Second, Mexico points out that the PLCAA applies only to 

actions "resulting from the criminal or unlawful misuse" of a 

firearm, and excludes any action in which the manufacturer or 

seller knowingly violated a "State or Federal statute" applicable 

to gun sales or marketing. Mexico argues that "criminal or 

unlawful misuse" should be read as referring only to violations of 

domestic laws, just as "convicted in any court" was read to 

encompass only domestic convictions in Small. Otherwise, Mexico 

says, the exception for knowing violations of law would presumably 

not be limited to state and federal statutes. We disagree. Given 

the basic concern motivating Congress, it makes perfect sense to 

read "criminal or unlawful misuse" broadly as including the 

violation of any law. Otherwise, Congress would have favored 

foreign plaintiffs over domestic plaintiffs and left a gaping hole 

in the shield that was the object of the legislation.

Mexico replies that Congress would not have required 

U.S. courts to interpret foreign criminal law in determining 

whether the use of a gun was "criminal or unlawful." Again, we 

disagree. Courts in the United States are capable of interpreting 

foreign law, and commonly do so. See, e.g., Piper Aircraft Co. v. 

Reyno, 454 U.S. 235, 245 (1981) ("[T]he mere fact that the court 

is called upon to determine and apply foreign law does not present 

a legal problem of the sort which would justify the dismissal of 

a case otherwise properly before the court." (internal quotations 
- 26 -

omitted)). Indeed, Mexico asks the court to interpret foreign law 

in this very case by arguing that Mexican law applies. To the 

extent Mexico is concerned that incorporating foreign law into the 

meaning of "criminal or unlawful use" will introduce "extreme" 

variations, the phrase already reflects the varied laws of fifty 

different states. See, e.g., Cynthia V. Ward, "Stand Your Ground" 

and Self-Defense, 42 Am. J. Crim. L. 89, 90 (2015) (describing 

contrasting state approaches to "stand your ground" laws). The 

PLCAA precludes certain lawsuits against firearm companies 

premised only on others' unlawful use of firearms -- regardless of 

which jurisdiction's law determines that the use was unlawful.

It also makes perfect sense that in crafting a specific 

and defined exception for knowing violations of law by a defendant, 

Congress would limit the exception to instances in which the 

defendant knowingly violated a "State or Federal statute." To do 

otherwise and except from the limitations of the PLCAA cases in 

which a manufacturer violated a law of a foreign country would 

grant foreign governments the ability to define the scope of that 

exception. See Small, 544 U.S. at 389–90 (finding Congress not to 

have granted foreign governments the ability to determine who could 

not own a gun in the United States). The PLCAA is designed to 

protect domestic firearm companies that operate lawfully in the 

United States under the numerous federal and state laws regulating 

their operations. See, e.g., 15 U.S.C. § 7901(a)(4) (finding that 
- 27 -

the U.S. gun industry is "heavily regulated by Federal, State, and

local laws"). That goal would be hampered if the PLCAA's 

protections fell away whenever a plaintiff alleged a violation of 

only foreign laws -- which may be significantly more restrictive 

than domestic regulations.

Third, Mexico argues that RJR Nabisco supports its claim 

that "damages . . . or other relief" covers only injury in the 

United States. RJR Nabisco involved the private right of action 

for "[a]ny person injured . . . by reason of a violation of" the 

Racketeer Influenced and Corrupt Organizations Act (RICO). 579 

U.S. at 346 (quoting 18 U.S.C. § 1964(c)). The Supreme Court held 

that the presumption against extraterritoriality precluded RICO's 

private right of action from applying to injuries suffered abroad. 

Id. But here, as discussed above, the focus of the PLCAA is not 

on redressing injury but rather on preventing certain lawsuits 

against U.S. firearm companies. So it is not an extraterritorial 

application of the PLCAA to bar a lawsuit in a U.S. court against 

a U.S. company for harm suffered abroad. See also WesternGeco, 

138 S. Ct. at 2138 (distinguishing "injury," a "substantive 

element of a cause of action" in RJR Nabisco, from "damages -- a 

separate legal concept").

Finally, Mexico argues that the term "any governmental 

entity" excludes foreign governmental entities because the PLCAA's 

factual findings refer to actions "commenced or contemplated by 
- 28 -

the Federal Government, States, municipalities, private interest 

groups and others," and do not expressly mention foreign 

governments. 15 U.S.C. § 7901(a)(8); id. § 7901(a)(7). This 

argument stumbles at the starting line. The statements in the 

findings of fact merely reflect that Congress enacted the PLCAA in 

response to actions that had been "commenced or contemplated" by 

the listed entities. They do not suggest that Congress did not 

intend for the PLCAA to apply to identical lawsuits by others that 

would have the same impact on the U.S. firearm industry.

In sum, the text, context, and purpose of the PLCAA all 

point toward a conclusion that "[q]ualified civil liability 

action[s]" include those filed in United States' federal and state 

courts by foreign governments for injury incurred abroad.

C.

The foregoing brings us to Mexico's last 

extraterritoriality argument: Its contention that our reading of 

the statute should give way to Mexico's invocation of international 

comity. Mexico argues that it is for Congress, not the courts, to 

decide whether to preclude a foreign-law claim for injuries 

incurred abroad -- especially when the plaintiff is a foreign 

sovereign. It therefore urges application of a clear-statement 

rule before reading a statute like the PLCAA to bar such lawsuits.

In making its comity argument, Mexico turns again to RJR 

Nabisco and its holding that RICO did not create a private cause 
- 29 -

of action for injuries suffered abroad. 579 U.S. at 346. In so 

holding, the Supreme Court reasoned that "providing a private civil 

remedy for foreign conduct creates a potential for international 

friction" because it risks "upsetting a balance of competing 

considerations that [foreign countries'] own . . . laws embody." 

Id. at 346–47 (quoting F. Hoffmann-La Roche Ltd. v. Empagran S.A., 

542 U.S. 155, 167 (2004)). Mexico contends that this case is the 

"mirror image" of RJR Nabisco: "[P]recluding a claim under 

[foreign] law for injury incurred [abroad]" interferes with 

foreign sovereigns' application of their laws just as much as 

"granting a claim under U.S. law for injury incurred abroad." Cf.

Nestlé USA, Inc. v. Doe, 141 S. Ct. 1931, 1948 (2021) 

(Sotomayor, J., concurring in part and concurring in the judgment) 

("Closing the courthouse doors . . . gives rise to foreign-policy 

concerns just as invariably as leaving them open." (cleaned up)). 

Therefore, Mexico argues, absent a clear statement from Congress,

courts should not apply the PLCAA to claims arising under foreign 

law for conduct that occurs in the United States but causes 

injuries abroad.

We decline to adopt this clear-statement rule for the 

PLCAA. As should be abundantly clear by now, the PLCAA's focus is 

on protecting U.S. firearm companies from certain costly lawsuits, 

thereby also preserving U.S. citizens' access to firearms. 

Creating an atextual exception for lawsuits by foreign governments 
- 30 -

would expose U.S. firearm companies to the very type of lawsuit 

the PLCAA seeks to prohibit, thereby running contrary to its stated 

goals. In at least this respect, this case is different from RJR 

Nabisco, in which limiting RICO's private cause of action to 

exclude injuries suffered abroad did not undermine any stated 

purposes of the statute.

The practical consequence of applying the PLCAA to this 

case is not lost on us. It may be that Mexico, as it claims, would 

be unable to pursue its lawsuit in the only forum that could 

provide effective injunctive relief. But that is a necessary 

consequence of Congress's decision to protect the U.S. firearm 

industry by regulating the types of lawsuits that can be 

adjudicated by U.S. courts. And the prohibition applies to 

lawsuits filed by domestic entities and individuals on an equal 

basis. Cf. Pfizer, 434 U.S. at 318–19 ("[A] foreign nation is 

generally entitled to prosecute any civil claim in the courts of 

the United States upon the same basis as a domestic corporation or 

individual might do.").

In sum, we hold that the PLCAA applies to lawsuits by 

foreign governmental entities for harm suffered outside this 

country, just as it applies to lawsuits by domestic governmental 

entities for harm suffered in this country. We turn next to 

Mexico's contention that, even if the PLCAA applies generally to 
- 31 -

suits by foreign governments for foreign harms, it also excepts 

from its ban claims of the type presented in Mexico's complaint. 

IV.

As the title of the Protection of Lawful Commerce in 

Arms Act suggests, the statute is designed to protect only "lawful" 

commerce in arms. It contains various exceptions to ensure that 

it does not insulate firearm companies against lawsuits resulting 

from their unlawful behavior. One of those exceptions, known as 

the predicate exception, exempts from the PLCAA's clutches "an 

action in which a manufacturer or seller of a qualified product 

knowingly violated a State or Federal statute applicable to the 

sale or marketing of the product, and the violation was a proximate 

cause of the harm for which relief is sought." 15 U.S.C. 

§ 7903(5)(A)(iii). Mexico contends that its lawsuit meets this 

description.

Defendants advance three arguments for rejecting 

Mexico's contention: first, defendants say that Mexico's claims 

are not for violations of "statute[s]"; second, they contend that

Mexico's complaint does not adequately plead violations of 

predicate statutes; and third, they assert that Mexico has not 

adequately alleged proximate cause. We conclude that Mexico 

survives each of these threshold challenges at this stage of the 

litigation. We therefore hold that the PLCAA does not prevent 

this case from moving forward. Our reasoning follows.
- 32 -

A.

The district court held that Mexico's common law claims 

did not qualify for the predicate exception because, it thought, 

the exception applies only to "statutory claims," not "common-law 

causes of action." Estados Unidos Mexicanos, 633 F. Supp. 3d at

446. Said differently, the district court thought that the "State 

or Federal statute" that the defendant violated, rather than the 

common law, must also provide the private right of action under 

which the plaintiff sues.

Mexico tells us that no other court has construed the 

PLCAA this way, and points to a variety of decisions applying the 

predicate exception to common law claims alleging knowing 

violations of statutes.4 Defendants do not contest this assertion, 

nor do they cite any cases construing the PLCAA as the district 

court did in this case. 

4 See, e.g., Brady v. Walmart Inc., No. 8:21-cv-1412-AAQ, 

2022 WL 2987078, at *6–10 (D. Md. July 28, 2022); Prescott v. Slide 

Fire Sols., LP, 410 F. Supp. 3d 1123, 1139–40 & 1139 n.9 (D. Nev. 

2019); Corporan v. Wal-Mart Stores E., LP, No. 16-2305-JWL, 2016 

WL 3881341, at *3–4 & *4 n.4 (D. Kan. July 18, 2016); City of New 

York v. A-1 Jewelry & Pawn, Inc., 247 F.R.D. 296, 353 (E.D.N.Y. 

2007); King v. Klocek, 187 A.D.3d 1614, 1616 (N.Y. App. Div. 2020); 

Englund v. World Pawn Exch., LLC, No. 16CV00598, 2017 WL 7518923, 

at *4 (Or. Cir. Ct. June 30, 2017); Chiapperini v. Gander Mountain 

Co., 13 N.Y.S.3d 777, 787 (N.Y. Sup. Ct. 2014); Williams v. 

Beemiller, Inc., 100 A.D.3d 143, 150–51 (N.Y. App. Div. 2012), 

amended by 103 A.D.3d 1191 (N.Y. App. Div. 2013); Smith & Wesson 

Corp. v. City of Gary, 875 N.E.2d 422, 434–35 (Ind. Ct. App. 2007).
- 33 -

We, too, conclude that the predicate exception 

encompasses common law claims in addition to statutory claims, as 

long as there is a predicate statutory violation that proximately 

causes the harm. The text of the PLCAA compels this conclusion. 

While other PLCAA exceptions exempt suits "for" specific causes of 

action, 15 U.S.C. § 7903(5)(A)(ii), (iv), (v) ("an action . . . 

for negligent entrustment or negligence per se"; "an action for 

breach of contract or warranty"; "an action for [harm arising from 

a product defect]"), the predicate exception more broadly exempts 

actions "in which" the manufacturer or seller violated a statute, 

id. § 7903(5)(A)(iii). If Congress had wanted to limit the 

predicate exception to claims for violating a predicate statute, 

it could have simply phrased this exception the same as the others. 

See Keene Corp. v. United States, 508 U.S. 200, 208 (1993) 

("[W]here Congress includes particular language in one section of 

a statute but omits it in another . . ., it is generally presumed 

that Congress acts intentionally and purposely in the disparate 

inclusion or exclusion." (omission in original) (quoting Russello

v. United States, 464 U.S. 16, 23 (1983))).

Defendants reply that "in which" means that the 

statutory violation must be contained "in" the cause of action, 

such that it must be an element of the claim. Certainly to prevail 

Mexico would need to prove a manufacturer or seller liable for the 

knowing violation of a statute applicable to the sale or marketing 
- 34 -

of a qualified product. So proof of a statutory violation is a 

condition to prevailing on, for example, a cause of action for 

negligence. But that does not mean that a lawsuit for negligence 

cannot be "an action in which . . . a seller . . . knowingly 

violated" a requisite statute. 

The predicate exception's proximate cause requirement 

harmonizes well with this understanding. The requisite proximate 

cause serves as a nexus between the predicate statutory violation 

and common law claims that otherwise might bear no relation to a 

seller's transgression of firearm statutes. This ensures 

that -- contrary to defendants' protestations -- our reading of 

the predicate exception does not allow any claim at all to proceed 

merely because it is alleged in the same case as an unrelated 

statutory violation.

The proximate cause requirement makes less sense under 

the district court's reading. Courts "generally presume that a 

statutory cause of action is limited to plaintiffs whose injuries 

are proximately caused by violations of the statute." Lexmark 

Int'l, Inc. v. Static Control Components, Inc., 572 U.S. 118, 132 

(2014). And for any statutory cause of action containing a 

proximate cause requirement (as most do), the district court's 

reading would render the identical requirement of the predicate 

exception entirely superfluous. See Consumer Data Indus. Ass'n v. 

Frey, 26 F.4th 1, 7 (1st Cir. 2022) ("A statute . . . ought to be 
- 35 -

construed in a way that 'no clause, sentence, or word shall be 

superfluous, void, or insignificant.'" (quoting Duncan v. Walker, 

533 U.S. 167, 174 (2001))). Of course, as defendants point out, 

not all statutory causes of action have a built-in proximate cause 

requirement. But even with this caveat, proximate cause makes far 

more sense as a nexus between a predicate statutory violation and 

other causes of action than as a catchall designed to graft a 

proximate cause requirement onto rare statutory causes of action 

with alternative causation frameworks. 

The examples Congress provided of lawsuits that fit 

within the exception dispel any doubt that the exception allows 

for more than purely statutory causes of action. The predicate 

exception expressly encompasses, as an example of allowed 

lawsuits, "any case in which the manufacturer or seller aided, 

abetted, or conspired with any other person to sell or otherwise 

dispose of a qualified product, knowing, or having reasonable cause 

to believe, that the actual buyer of the qualified product was 

prohibited from possessing or receiving a firearm or ammunition

under subsection (g) or (n) of section 922 of title 18, United 

States Code" -- conduct made unlawful by the Gun Control Act, 18 

U.S.C. § 922(d). 15 U.S.C. § 7903(5)(A)(iii)(II). Yet, nothing 

in section 922 seems to create any private right of action. Nor 

does any party suggest that it does. To the contrary, Mexico cites 

various cases holding that the Gun Control Act contains no 
- 36 -

statutory private right of action, and defendants do not dispute 

this characterization.5 And given that agreed-upon reading, it 

would make no sense for Congress to have listed such a case as an 

example if only statutory actions could survive under the predicate 

exception.

Defendants argue that, read to include non-statutory 

causes of action, the predicate exception would "wholly subsume" 

a different exception in the PLCAA for "action[s] brought against 

a seller for . . . negligence per se." 15 U.S.C. § 7903(5)(A)(ii). 

Generally speaking, negligence per se requires violation of "a 

statute that is designed to protect against the type of 

accident the actor's conduct causes" and that the "victim is within 

the class of persons the statute is designed to protect." 

Restatement (Third) of Torts § 14. Defendants complain that our 

reading of the predicate exception would allow plaintiffs to bring 

any common law claim based on any statutory violation, thereby 

rendering these restrictions superfluous. 

5 The cases that Mexico cites are not from this circuit. See

Bannerman v. Mountain State Pawn, Inc., No. 3:10-CV-46, 2010 WL 

9103469 (N.D. W. Va. Nov. 5, 2010), aff'd, 436 F. App'x 151 (4th 

Cir. 2011); Est. of Pemberton v. John's Sports Ctr., Inc., 135 

P.3d 174 (Kan. Ct. App. 2006); T & M Jewelry, Inc. v. Hicks ex 

rel. Hicks, 189 S.W.3d 526 (Ky. 2006). We do not decide here 

whether the Gun Control Act provides a private right of action. 

For purposes of the present case, we merely accept the parties' 

apparent agreement that it does not.
- 37 -

Defendants' argument glosses over the heightened mens 

rea requirement in the predicate exception, which applies only 

when the defendant "knowingly" violates a statute. So there are 

statutory violations -- i.e., those that are not "knowing" -- that 

may be actionable under the doctrine of negligence per se but do 

not serve as predicate violations. So, there is no superfluousness 

in our reading of the statute. And it is perfectly sensible for 

Congress to allow claims satisfying the negligence per se standard 

to proceed, while at the same time creating a separate exception 

for knowing violations of statutes regulating the sale or marketing 

of firearms.6

For these reasons, we conclude that the predicate 

exception allows common law claims for injury proximately caused 

by a defendant's knowing violation of a predicate statute. We 

turn next to defendants' contention that Mexico has not adequately 

alleged such a violation.

B.

Mexico alleges that defendants knowingly violated 

predicate statutes in two ways: by aiding and abetting illegal 

downstream sales, and by selling unlawful "machineguns."

6 In fact, the district court in this very case found the 

negligence per se exception inapplicable because Massachusetts 

does not recognize the negligence per se doctrine. See Estados 

Unidos Mexicanos, F. Supp. 3d at 449.
- 38 -

1.

First, Mexico reasons that by deliberately facilitating 

the unlawful trafficking of their guns into Mexico, defendants aid 

and abet violations of various federal statutes that prohibit

selling guns without a license, exporting guns without a license, 

and selling to straw purchasers. Resting on their position that 

the predicate exception is limited to statutory causes of action 

(which we have rejected), defendants do not contend that the

complaint fails to allege widespread sales of firearms by dealers 

in knowing violation of several state and federal statutes. Nor 

do defendants dispute that the predicate exception of 

section 7903(5)(A)(iii) would apply if Mexico were to prove that 

a defendant aided and abetted any such violation. Instead, 

defendants contend that even for pleading purposes the complaint 

fails to allege facts plausibly supporting the theory that 

defendants have aided and abetted such unlawful sales.

We disagree, finding instead that Mexico's complaint 

adequately alleges that defendants have been aiding and abetting 

the sale of firearms by dealers in knowing violation of relevant 

state and federal laws. "[T]he essence of aiding and abetting" is

"participation in another's wrongdoing that is both significant 

and culpable enough to justify attributing the principal 

wrongdoing to the aider and abettor." Twitter, Inc. v. Taamneh, 

598 U.S. 471, 504 (2023). 
- 39 -

Reduced to its essence, aiding-and-abetting liability 

rests on "twin requirements" that the assistance provided to the 

principal wrong-doer be both (1) "knowing" and (2) "substantial." 

Id. at 491-92. These requirements "work[] in tandem, with a lesser 

showing of one demanding a greater showing of the other." Id. 

They "'should be considered relative to one another' as part of a 

single inquiry designed to capture conscious and culpable 

conduct." Id. at 504 (quoting Camp v. Dema, 948 F.2d 455, 459 

(8th Cir. 1991)).

Defendants argue that Mexico has at best alleged 

defendants' knowing indifference to the downstream illegal 

trafficking of their guns into Mexico. They argue that "because 

Defendants themselves are not alleged to 'participate' in this 

wrongful conduct at all, much less with any plausible intent of 

facilitating it, they cannot be deemed accomplices."

This argument reflects a fundamental misunderstanding of 

the complaint. Fairly read, the complaint alleges that defendants 

are aware of the significant demand for their guns among the 

Mexican drug cartels, that they can identify which of their dealers 

are responsible for the illegal sales that give the cartels the 

guns, and that they know the unlawful sales practices those dealers 

engage in to get the guns to the cartels. The complaint further 

alleges that even with all this knowledge, and even after warnings 

from the U.S. government, defendants continue to supply the very 
- 40 -

dealers that they know engage in straw sales and large-volume sales 

to traffic guns into Mexico, that they design military-style 

weapons and market them as such knowing that this makes them more

desirable to the cartels, and that they place serial numbers on 

their weapons in a manner that facilitates their removal, as is 

preferred by cartels. And the complaint alleges that as a result 

of this conduct, defendants collectively reap $170 million per 

year in revenue from this illegal market. It is therefore not 

implausible that, as the complaint alleges, defendants engage in 

all this conduct in order to maintain the unlawful market in 

Mexico, and not merely in spite of it.

Notionally, imagine a dealer, a distributor, and a 

manufacturer standing abreast of one another at the border. The 

manufacturer hands the distributor ten guns, the distributor hands 

them to the dealer, and the dealer then hands them to a group of 

ten customers, among whom there are eight well-known agents of the 

cartel acting as straw purchasers. Rather than refusing to fill 

an order for ten more guns by that dealer, the manufacturer tweaks 

its advertisements to better appeal to the cartel, supplies them 

more guns, and so on over and over again. We think it clear that 

by passing along guns knowing that the purchasers include unlawful 

buyers, and making design and marketing decisions targeted towards 

those exact individuals, the manufacturer is aiding and abetting 
- 41 -

illegal sales. And this scenario, in substance, is fairly 

analogous to what Mexico alleges.

The allegations here are also remarkably analogous to 

the facts in Direct Sales Co. v. United States, 319 U.S. 703 

(1943). In that case, the defendant company conducted from New 

York a business providing mail-order prescription drugs to doctors 

around the country. Id. at 704–06. One customer was a doctor in 

South Carolina who was illegally reselling morphine sulfate 

supplied to him by the defendant. Id. at 704. The defendant was 

convicted of criminally conspiring with the doctor. Id. at 704-05. 

In affirming the conviction, the Supreme Court pointed to evidence 

that the doctor was ordering the product in large volumes 

incompatible with lawful use by legitimate patients, that the 

defendant facilitated this behavior through mass advertising and 

offering bulk sales at steep discounts (even after the U.S. 

government warned it that it was a source of supply for an illegal 

market), and that the company had a "stake in the venture" in the 

form of profits from the illegally sold drugs. Id. at 706–07, 

712–13. From this evidence, the Court concluded, the jury could 

have found beyond a reasonable doubt that the defendant supplier 

"not only kn[ew] and acquiesce[d]" in the illegal enterprise, but 

also "join[ed] both mind and hand . . . to make its accomplishment 

possible." Id. at 713.
- 42 -

Here, similarly, the complaint alleges that defendants 

have resisted taking measures that would make it more difficult 

for their firearms to fall into the cartels' hands (despite 

warnings from the U.S. government), that they design and market 

their guns in such a way as to make them attractive to the illegal 

market, and that they benefit financially as a result. And unlike 

in Direct Sales, the defendants here are alleged to know that they 

supply dealers who sell illegally, making the inference that they 

are working in concert with these unlawful actors even stronger. 

Neither must we determine whether there is evidence of these facts 

sufficient to support a criminal conviction as in Direct Sales; we 

ask only whether the facts alleged in the complaint plausibly 

support an aiding-and-abetting theory of liability in this civil 

case. Direct Sales strongly supports our conclusion that they do.

Defendants attempt to distinguish Direct Sales by

relying on the Court's observation that given the quantities sold 

the drugs could not have all been used for any lawful purpose. 

Id. at 710–12. In contrast, they assert, the "vast majority of 

retailers" are law-abiding and "only 2%" of U.S. firearms end up 

in Mexico. But in Direct Sales the Court distinguished 

morphine -- a product "incapable of further legal use except by 

compliance with rigid regulations" -- from other commodities "not 

restricted as to sale by order form, registration, or other 

requirements." Id. at 710. The defendant's sales methods and 
- 43 -

volumes, which might be perfectly innocuous for everyday items, 

were evidence of illicit intent when employed to sell a dangerous 

item whose legitimate market is highly restricted. Id. at 711-12. 

"The difference," the Court said, "is like that between toy pistols 

or hunting rifles and machine guns." Id. at 710. 

And so in Direct Sales the defendant must have known 

that the sales volume meant there were likely illegal sales, and 

by encouraging volume sales, the defendant could have been found 

to have intended to supply the products for the illegal sales. 

Here we also have a highly regulated product7 allegedly being sold 

in an illegal manner, and an allegation that defendants know what 

is going on and take steps to facilitate it. In this important 

respect, Direct Sales again provides a close and instructive 

analogy. 

Defendants also point out that Direct Sales rejected the 

proposition that a seller could be held liable for a buyer's 

illegal acts based merely on their knowledge or lack of concern as 

to the buyer's unlawful plans. But for all the reasons described 

above, the complaint adequately alleges that defendants make 

deliberate design and distribution choices to facilitate the 

illegal trafficking of their guns to Mexico. Thus they are not 

7 As Congress observed in enacting the PLCAA, "[t]he 

manufacture, importation, possession, sale, and use of firearms 

and ammunition in the United States are heavily regulated." 15 

U.S.C. § 7901(a)(4). 
- 44 -

mere passive observers of the buyer's illegal activity, but more 

akin to a calculated and willing participant in the supply chain 

that ends with a profitable illegal firearm market in Mexico.

Defendants argue that the Supreme Court's recent opinion 

in Twitter calls for a different result. We disagree. In Twitter, 

the Supreme Court held that major social media platforms used by 

ISIS to enlist recruits and raise funds were not liable under the 

Justice Against Sponsors of Terrorism Act for aiding and abetting 

an ISIS terrorist attack on a nightclub in Turkey. 598 U.S. at 

505-07. The defendants in Twitter had no meaningful stake in 

ISIS's use of their platforms and had an undisputed lack of intent 

to support ISIS. Id. The only affirmative conduct that the 

defendants engaged in was creating their platforms and making them 

available to the public, which was not alleged to have been done 

with ISIS in mind or to support terrorism. Id. at 498. There was 

also no allegation that ISIS even used the platforms to plan or 

coordinate the attack. Id. 

Here, by contrast, Mexico alleges that defendants engage 

in conduct -- design decisions, marketing tactics, and repeated 

supplying of dealers known to sell guns that cross the 

border -- with the intent of growing and maintaining an illegal 

market in Mexico from which they receive substantial revenues. 

And for Rule 12(b)(6) purposes we assume that defendants' conduct 

in fact helped incite the unlawful sales. See, e.g., SBT Holdings, 
- 45 -

LLC v. Town of Westminster, 547 F.3d 28, 35 (1st Cir. 2008) ("[W]e 

draw all rational inferences from the facts alleged in favor of 

the plaintiffs."). Defendants are therefore alleged to be much 

more active participants in the alleged activity than were the

Twitter defendants, and the holding in that case does not compel 

a different result in this one. 

Of course, the complaint does not allege defendants' 

awareness of any particular unlawful sale. But neither did the 

convicted mail-order company in Direct Sales have such specific 

knowledge. The Supreme Court clarified in Twitter that such a 

"strict nexus" is not always required. 598 U.S. at 497. "[I]n 

appropriate circumstances, a secondary defendant's role in an 

illicit enterprise can be so systemic that the secondary defendant 

is aiding and abetting every wrongful act committed by that 

enterprise." Id. at 496. Here, defendants operate at a systemic 

level, allegedly designing, marketing, and distributing their guns 

so that demand by the cartels continues to boost sales. In these 

circumstances, defendants need not know about any particular 

unlawful sale that funnels their guns into Mexico. 

In sum, we conclude that the complaint adequately 

alleges that defendants aided and abetted the knowingly unlawful 

downstream trafficking of their guns into Mexico. Defendants' 

arguments to the contrary are premised either on an inaccurate

reading of the complaint or on a misapplication of the standard of 
- 46 -

review on a motion to dismiss under Rule 12(b)(6). Whether 

plaintiffs will be able to support those allegations with evidence 

at summary judgment or at trial remains to be seen. At this stage, 

though, we must "accept all well-pleaded allegations of [Mexico]

as true and afford all inferences in [Mexico's] favor." VázquezRamos v. Triple-S Salud, Inc., 55 F.4th 286, 291 (1st Cir. 2022)

(cleaned up) (quoting Arroyo-Melecio v. P.R. Am. Ins. Co., 398 

F.3d 56, 65 (1st Cir. 2005)).

2.

Mexico's argument that defendants unlawfully sold 

"machineguns" fares less well. The Gun Control Act prohibits 

selling a "machinegun" without specific authorization. 18 U.S.C. 

§ 922(b)(4). "Machinegun" is defined as follows:

The term "machinegun" means any weapon which 

shoots, is designed to shoot, or can be 

readily restored to shoot, automatically more 

than one shot, without manual reloading, by a 

single function of the trigger. The term 

shall also include the frame or receiver of 

any such weapon, any part designed and 

intended solely and exclusively, or 

combination of parts designed and intended, 

for use in converting a weapon into a 

machinegun, and any combination of parts from 

which a machinegun can be assembled if such 

parts are in the possession or under the 

control of a person.

26 U.S.C. § 5845(b).

Mexico claims that defendants' semiautomatic weapons 

meet this definition because they can easily be modified to fire 
- 47 -

automatically. It cites a 1982 ATF administrative ruling stating 

that this definition "includes those weapons which have not 

previously functioned as machineguns but possess design features 

which facilitate full automatic fire by a simple modification or 

elimination of existing component parts." ATF Rul. 82-8, 1982-2 

A.T.F.Q.B. 49 (1982).

Binding precedent from the Supreme Court and this court 

forecloses Mexico's interpretation. In Staples v. United States, 

the Supreme Court held that the National Firearms Act -- which 

prohibits possession of an unregistered "machinegun" (as defined 

above) -- requires that the defendant knew that the possessed 

weapon "had the characteristics that brought it within the 

statutory definition of a machinegun." 511 U.S. 600, 602 (1994). 

The defendant in that case possessed an AR-15 rifle, in which 

certain components had been swapped out or filed down to enable 

automatic firing. Id. at 603. The Supreme Court held that to be 

properly convicted the defendant must have known that his rifle 

had been so modified. Id. at 619. It rejected a reading of the 

statute under which "any person who has purchased what he believes 

to be a semiautomatic rifle or handgun . . . can be subject to 

imprisonment, despite absolute ignorance of the gun's firing 

capabilities, if the gun turns out to be an automatic." Id.

at 615. And the majority also rejected the dissent's argument 

based on a class of "readily convertible semiautomatics" because 
- 48 -

"that class bears no relation to the definitions in the Act." Id.

at 612 n.6.

Similarly, in United States v. Nieves-Castaño, we 

reversed the conviction of a defendant who knew that she possessed 

an AK-47 but did not know that it had been modified to allow 

automatic firing. 480 F.3d 597, 602 (1st Cir. 2007). We stated 

that "[w]hile an automatic weapon meets the definition of a machine 

gun, a semi-automatic weapon does not." Id. at 600 (citing 

Staples, 511 U.S. at 602 & n.1).

Mexico argues that Staples and Nieves-Castaño are 

inapposite because those cases were about the mens rea requirement 

for a possession crime, not the definition of "machinegun." It 

cites a district court case from Nevada distinguishing Staples on 

this basis. See Parsons v. Colt's Mfg. Co., No. 19-cv-01189, 2020 

WL 1821306, at *5 (D. Nev. Apr. 10, 2020), modified on 

reconsideration, No. 19-cv-01189, 2020 WL 2309259 (D. Nev. May 8, 

2020). But critical to the holdings of both Staples and NievesCastaño was that knowing possession of a readily convertible 

semiautomatic weapon does not constitute de facto knowing 

possession of a "machinegun." In other words, a readily 

convertible semiautomatic weapon is not, without more, the same as

an automatic weapon. Mexico's reading would erase this 

distinction -- creating an equivalency that the holdings of Staples

and Nieves-Castaño do not allow. It would also effectively outlaw 
- 49 -

the knowing possession of any semiautomatic weapon, since

"virtually any semiautomatic weapon may be converted . . . into a 

machinegun within the meaning of the Act." See Staples, 511 U.S. 

at 615. Whether convertible semiautomatic weapons are to be 

prohibited in their entirety is not an issue presented by this

appeal. 

C.

The final hurdle that Mexico must clear is the predicate 

exception's proximate cause requirement. A violation of a 

predicate statute allows a lawsuit to proceed only if "the 

violation was a proximate cause of the harm for which relief is 

sought." 15 U.S.C. § 7903(5)(A)(iii).

Proximate cause "demand[s] 'some direct relation between 

the injury asserted and the injurious conduct alleged.'" United 

States v. Kilmartin, 944 F.3d 315, 330 (1st Cir. 2019) (quoting 

Paroline v. United States, 572 U.S. 434, 444 (2014)). "Proximate 

cause is commonly understood as a function of the foreseeability 

of the harm," id. at 331, although in certain contexts 

foreseeability alone may be insufficient, see, e.g., Bank of Am. 

Corp. v. City of Miami, 581 U.S. 189, 202 (2017) (Fair Housing 

Act).8

8 Neither party proposes a definition of proximate cause 

specific to the predicate exception of the PLCAA. In the absence 

of any such suggestions, we apply traditional understandings of 

proximate cause. 
- 50 -

Mexico's claim of proximate cause is straightforward: 

defendants aid and abet the trafficking of guns to the Mexican 

drug cartels, and this trafficking has foreseeably required the 

Mexican government to incur significant costs in response to the 

increased threats and violence accompanying drug cartels armed 

with an arsenal of military-grade weapons.

Defendants attempt to complicate this causal theory. 

They maintain that the chain of causation actually has eight steps: 

(1) manufacturers sell guns to distributors; (2) distributors sell 

the guns to dealers; (3) dealers sell the guns to buyers with 

illegal intentions; (4) those buyers sell the guns to smugglers or 

smuggle them into Mexico themselves; (5) the cartels buy the guns; 

(6) the cartels use the guns; (7) the cartels' use of the guns 

injures people and property in Mexico; and (8) the Mexican 

government suffers derivative financial harm from those injuries. 

There are at least two fatal flaws in this argument. 

First, the starting point for the predicate exception's 

causation analysis is the "violation" of "a State or Federal 

statute applicable to the sale or marketing" of firearms. We ask 

whether "the violation" proximately caused the plaintiff's harm. 

15 U.S.C. § 7903(5)(A)(iii). Here, the violation that defendants 

allegedly aid and abet occurs when a dealer knowingly violates the 

law in selling guns intended for cartels. Viewed in this light, 

the relevant chain of causation starts at step 3 of the defendants' 
- 51 -

list. And from that point, the Mexican government's expenditure 

of funds to parry the cartels is a foreseeable and direct 

consequence.

Second, the fact that one can fashion a multi-step 

description of the causal chain does not mean that the injurious 

conduct and the injury alleged are insufficiently connected. 

Consider a defendant who falls asleep at the helm of a large ship, 

leaning on the helm, so as to move the tiller, which turns the 

rudder, which then turns the ship off course, hitting and weakening

a dike, and thereby causing a reasonably cautious downstream farmer 

to build a levee. Surely the ability to describe this causation 

in multiple steps would not mean that, as a matter of law, the 

negligent helmsperson did not foreseeably cause the farmer 

compensable harm. Rather, one would more reasonably say that 

negligently steering the ship foreseeably caused the need to shoreup flood defenses. So, too, here, the complaint plausibly alleges 

that aiding and abetting the illegal sale of a large volume of 

assault weapons to the cartels foreseeably caused the Mexican 

government to shore-up its defenses. 

Defendants nevertheless claim that the Third Circuit 

adopted their view of proximate cause in City of Philadelphia v. 
- 52 -

Beretta U.S.A. Corp., 277 F.3d 415, 423–24 (3d Cir. 2002).9 In 

that case, though, Philadelphia alleged "[a]t most . . . awareness 

of the means by which prohibited purchasers end up possessing 

handguns." Id. at 424 & n.14. The "trace request information" 

available at that time "d[id] not put a gun manufacturer on notice 

that a specific distributor or dealer [wa]s engaged in unlawful 

firearm trafficking." Id. at 424 n.14. Thus all gun manufacturers 

knew was that "some handguns reach prohibited purchasers." Id. 

And without more, the plaintiffs could not show "intent on the 

part of the gun manufacturers." Id. Here, by contrast, Mexico 

expressly alleges that the defendants did know which dealers were 

making illegal sales. 

Defendants further contend that there is no proximate 

cause because the causal chain contains multiple criminal acts by 

third parties. They argue that "an 'intervening criminal act of 

a third party' is the textbook intervening act," Copithorne v. 

Framingham Union Hosp., 520 N.E.2d 139, 141 (Mass. 1988). But the 

complete sentence in Copithorne from which defendants' brief 

cherry-picks actually states: "The intervening criminal act of a 

third party is a superseding cause which breaks the chain of 

proximate causation only where the original wrongdoer reasonably 

9 The Third Circuit decided City of Philadelphia before 

Congress enacted the PLCAA, so it analyzed proximate cause under 

negligence law, not the PLCAA. 277 F.3d at 422–26.
- 53 -

could not have foreseen such act." Id.; see also, e.g., 

Restatement (Second) of Torts § 448 (intervening crime is 

superseding cause "unless the actor at the time of his negligent 

conduct realized or should have realized the likelihood . . . that 

a third person might avail himself of the opportunity to commit 

such a . . . crime"); id. § 449 ("If the likelihood that a third 

person may act in a particular manner is the hazard or one of the 

hazards which makes the actor negligent, such an act whether 

innocent, negligent, intentionally tortious, or criminal does not 

prevent the actor from being liable for harm caused thereby."). 

Here, the complaint alleges not only that it was foreseeable that 

defendants' guns would end up in the hands of Mexican cartels, but 

also that defendants actually intended to bring about that result. 

And it is certainly foreseeable that Mexican drug cartels -- armed 

with defendants' weapons -- would use those weapons to commit 

violent crimes. The acts of these third parties are therefore 

properly considered as part of the proximate causation chain. 

Defendants' superseding-criminal-act argument is 

especially unconvincing in the context of the PLCAA, which 

precludes only those claims "resulting from the criminal or 

unlawful misuse of a qualified product" by someone other than the 

defendant. 15 U.S.C. § 7903(5)(A). If a third party's unlawful 

act always undercuts proximate cause, the predicate exception 

would be meaningless. See Abramski v. United States, 573 U.S. 
- 54 -

169, 183 n.8 (2014) (rejecting an interpretation of a gun-control 

statute that "would render the statute all but useless").

Defendants then shift focus from the conduct to the 

injury. They argue that the Mexican government's alleged harms 

are wholly derivative of injuries suffered by the direct victims 

of cartel violence, citing a "general tendency of the law" not to 

stretch proximate causation "beyond [its] first step" to reach 

indirect victims. Holmes v. Sec. Inv. Prot. Corp., 503 U.S. 258, 

271 (1992) (quoting Associated Gen. Contractors v. Cal. State 

Council of Carpenters, 459 U.S. 519, 534 (1983)). Under this 

principle, "a plaintiff who complained of harm flowing merely from 

the misfortunes visited upon a third person by the defendant's 

acts was generally said to stand at too remote a distance to 

recover." Id. at 268–69; see also Lexmark, 572 U.S. at 133.

Some courts have applied this principle to bar similar 

lawsuits by cities against gun manufacturers. For example, the 

Third Circuit held that Philadelphia had not alleged proximate 

cause because it sought "reimbursement for expenses that arise 

only because of the use of firearms to injure or threaten City 

residents," even though some of the alleged damages were "different 

from the damages suffered by direct victims of gun 

violence" -- like costs to "investigate and prosecute gun 

trafficking[ and] to patrol gun infested neighborhoods." City of 
- 55 -

Philadelphia, 277 F.3d at 425; see also Ganim v. Smith & Wesson 

Corp., 780 A.2d 98, 124 (Conn. 2001) (applying similar reasoning).

On the other hand, some courts have recognized that 

selling guns into an illegal market may cause direct harm to a 

governmental entity that is not derivative of harm to its 

residents. A court in Massachusetts allowed the city of Boston to 

proceed in its lawsuit against firearm companies where the city 

alleged various direct harms resulting from the defendants' 

"fueling an illicit market" of guns. City of Boston v. Smith & 

Wesson Corp., No. 199902590, 2000 WL 1473568, at *6 (Mass. Super. 

July 13, 2000). Such harms included costs of increased security 

at public schools, costs of increased law enforcement, lower 

property values, and diminished tax revenues. Id. The Supreme 

Court of Ohio adopted this reasoning, finding direct injuries in 

the form of "significant expenses for police, emergency, health, 

prosecution, corrections and other services." Cincinnati v. 

Beretta U.S.A. Corp., 768 N.E.2d 1136, 1148 (Ohio 2002). 

Similarly, a New Jersey court rejected a remoteness argument with 

respect to expenditures associated with "deterrence, investigation 

of gun crimes, and other related services." James v. Arms Tech., 

Inc., 820 A.2d 27, 41 (N.J. Super. Ct. App. Div. 2003); see also

In re JUUL Labs, Inc., Mktg., Sales Practices & Prods. Liab. 

Litig., 497 F. Supp. 3d 552, 664-65 (N.D. Cal. 2020) (finding 
- 56 -

proximate cause where government entities "do not seek to recover 

costs expended by . . . any other third party").

We find the reasoning of the latter cases persuasive. 

When faced with an epidemic of unlawful gun trafficking into its 

country, a government will foreseeably -- indeed 

inexorably -- incur costs of its own that are not merely derivative 

of those borne by the direct victims of gun violence. One obvious 

example is the cost of increased law enforcement personnel and 

training to mitigate the flow of illegal weapons and to combat 

drug cartels that -- armed with defendants' weapons -- are 

essentially hostile military operations. The government directly 

and uniquely bears these costs as a direct result of defendants' 

alleged facilitation of gun trafficking to the Mexican cartels. 

Imagine that a U.S. company sent a mercenary unit of 

combat troops to attack people in Mexico City. Such an attack 

would directly cause Mexico itself the expense of paying soldiers 

to defend the city. Proximate cause would be quite clear. So, 

too, here, where the defendants are alleged to have armed the 

attackers for their continuing assaults. 

Mexico may also be able to show that other of its alleged 

harms are proximately caused by defendants' actions, and not merely 

derivative of harms to its citizens. For example, if Mexico can 

prove that it had to proactively spend more funds to bolster its 

healthcare facilities, social services, and judicial system in 
- 57 -

response to the cartels' accumulation of defendants' guns, these 

expenses might also not be merely derivative of the injuries 

suffered by individual victims. On the other hand, other alleged 

harms, such as lower economic efficiency due to the decreased size 

of the working population, are derivative because the harm to the 

government flows only from prior harm inflicted upon its citizens. 

The bottom line is that Mexico has plausibly alleged at least some 

injuries that it has suffered directly from the illegal trafficking 

of guns into Mexico, and that are not merely derivative of the 

harm suffered by the victims of gun violence.

This conclusion is consistent with Supreme Court 

precedent. In Holmes (a RICO case), the Court held that there was 

no proximate cause linking the defendants' manipulation of stock 

prices, which caused broker-dealers who purchased the stock to 

experience financial distress, to the harm suffered by the brokerdealers' customers when the broker-dealers could not pay the 

customers' claims. 503 U.S. at 271–74. In that case, the only 

path from the stock manipulation to the customers' harm was through 

the broker-dealers' harm. Id. at 271 ("[T]he conspirators have 

allegedly injured these customers only insofar as the stock 

manipulation first injured the broker-dealers and left them 

without the wherewithal to pay customers' claims.").

Contrast the situation in Holmes from one contemplated 

by the Court in Lexmark:
- 58 -

Consider two rival carmakers who purchase 

airbags for their cars from different thirdparty manufacturers. If the first carmaker, 

hoping to divert sales from the second, 

falsely proclaims that the airbags used by the 

second carmaker are defective, both the second 

carmaker and its airbag supplier may suffer 

reputational injury, and their sales may 

decline as a result. In those circumstances, 

there is no reason to regard either party's 

injury as derivative of the other's; each is 

directly and independently harmed by the 

attack on its merchandise.

572 U.S. at 138–39.

This case is more like the airbag example in Lexmark

than the stock manipulation in Holmes. Unlike in Holmes, the 

causal path from the gun trafficking to the Mexican government's 

expenditures does not flow solely through the harm suffered by 

victims of gun violence. Rather, like in the airbag example, the 

harm caused by the trafficking goes in multiple directions -- both 

directly to the victims of gun violence and directly to the Mexican 

government. Admittedly, the government's expenditures are 

presumably in large part for the purpose of preventing and 

mitigating the harm from gun violence to its citizens. But that 

does not make it "purely derivative" in the sense that sometimes 

defeats proximate cause. See id. at 133. 

Defendants' final attack on proximate cause is a 

pragmatic one. Defendants point to two "functional factors" that 

courts apply while analyzing proximate cause under RICO: the 

feasibility of "ascertain[ing] the amount of a plaintiff's damages 
- 59 -

attributable to the violation, as distinct from other, 

independent, factors"; and the "administrability" of apportioning 

damages without "multiple recoveries." Sterling Suffolk 

Racecourse, LLC v. Wynn Resorts, Ltd., 990 F.3d 31, 35-36 (1st 

Cir. 2021) (quoting In re Neurontin Mktg. & Sales Pracs. Litig., 

712 F.3d 21, 35–36 (1st Cir. 2013)).

Assuming these considerations apply outside of the RICO 

context, they would not require the dismissal of the complaint in 

this case. The foregoing discussion concerning Mexico's nonderivative harm disposes of defendants' concern about multiple 

recoveries. We are also not persuaded that determining the damages 

attributable to each defendant will be as difficult as defendants 

suggest. And in this case any such difficulties are best resolved 

once Mexico has had an opportunity to engage in discovery and 

submit expert reports bearing on damages. Accord City of Boston, 

2000 WL 1473568, at *7 n.33 ("The difficulty in ascertaining 

damages in this case is best assessed when the case has gone beyond 

the pleading stage."). In any event, Mexico seeks injunctive 

relief in addition to damages, and defendants' concerns about 

double recoveries and apportioning damages do not apply to 

injunctive relief. Cf. Lexmark, 572 U.S. at 135 ("Even when a 

plaintiff cannot quantify its losses with sufficient certainty to 

recover damages, it may still be entitled to injunctive 

relief . . . .").
- 60 -

We conclude that Mexico has adequately alleged proximate 

causation, thereby satisfying the final demand of the predicate 

exception. Of course, our holding at this stage is based on the 

allegations in the complaint, construed favorably to Mexico. 

Mexico will have to support its theory of proximate causation with 

evidence later in the proceedings.

V.

The parties' briefing touches on certain issues beyond 

the PLCAA, including which jurisdiction's law governs Mexico's 

tort claims and whether defendants owe a duty to Mexico under 

whichever tort law does apply. The district court did not reach 

these issues because it found the PLCAA dispositive. Having 

concluded that the PLCAA does not bar Mexico's lawsuit at this 

stage of the proceedings, we think it prudent to allow the district 

court to address the remaining issues in the first instance, rather 

than deciding them ourselves without the benefit of the district 

court's analysis or focused briefing from the parties.

VI.

For the foregoing reasons, we reverse the district 

court's conclusion that the PLCAA bars Mexico's tort claims and 

remand to the district court for further proceedings consistent 

with this opinion.