Syllabus

NOTE: Where it is feasible, a syllabus (headnote) will be released, as is being done in connection with this case, at the time the opinion is issued. The syllabus constitutes no part of the opinion of the Court but has been prepared by the Reporter of Decisions for the convenience of the reader. See United States v. Detroit Timber & Lumber Co., 200 U. S. 321, 337.

SUPREME COURT OF THE UNITED STATES

Syllabus

SMITH & WESSON BRANDS, INC., ET AL. v. ESTADOS UNIDOS MEXICANOS CERTIORARI TO THE UNITED STATES COURT OF APPEALS FOR THE FIRST CIRCUIT

No. 23–1141. Argued March 4, 2025—Decided June 5, 2025 The Protection of Lawful Commerce in Arms Act (PLCAA) bars certain lawsuits against manufacturers and sellers of firearms. As relevant, it provides that a “qualified civil liability action . . . may not be brought in any Federal or State court,” 15 U. S. C. §7902(a), and defines that term to include a “civil action or proceeding” against a firearms man- ufacturer or seller stemming from “the criminal or unlawful misuse” of a firearm by “a third party,” §7903(5)(A). But PLCAA’s general bar on these suits has an exception, usually called the predicate exception, relevant here. That exception applies to lawsuits in which the defend- ant manufacturer or seller “knowingly violated a State or Federal stat- ute applicable to the sale or marketing” of firearms, and the “violation was a proximate cause of the harm for which relief is sought.” §7903(5)(A)(iii). The predicate violation PLCAA demands may come from aiding and abetting someone else’s firearms offense. PLCAA itself lists as exam- ples two ways in which aiding and abetting qualifies—when a gun manufacturer (or seller) aids and abets another person in making a false statement about a gun sale’s legality or in making specified crim- inal sales. See §7903(5)(A)(iii)(I)–(II). And more broadly, because fed- eral law provides that whoever “aids [and] abets” a federal crime “is punishable as a principal,” 18 U. S. C. §2(a), a gun manufacturer that aids and abets a federal gun crime may itself commit a PLCAA predi- cate violation. Here, the Government of Mexico sued seven American gun manu- facturers, alleging that the companies aided and abetted unlawful gun sales that routed firearms to Mexican drug cartels. The basic theory of its suit is that the defendants failed to exercise “reasonable care” to 2 SMITH & WESSON BRANDS, INC. v. ESTADOS UNIDOS MEXICANOS Syllabus

prevent trafficking of their guns into Mexico, and so are responsible for the harms arising there from the weapons’ misuse. That theory implicates PLCAA’s general prohibition, so the complaint tries to plead its way into the predicate exception. It alleges that the manu- facturers were “willful accessories” in unlawful gun sales by retail gun dealers, which in turn enabled Mexican criminals to acquire guns. And it sets out three kinds of allegations relating to how the manufac- turers aided and abetted retailers’ unlawful sales: The manufacturers allegedly (1) supply firearms to retail dealers whom they know illegally sell to Mexican gun traffickers; (2) have failed to impose the kind of controls on their distribution networks that would prevent illegal sales to Mexican traffickers; and (3) make “design and marketing decisions” intended to stimulate cartel members’ demand for their products. The District Court dismissed the complaint, but the First Circuit reversed, finding Mexico had plausibly alleged that defendants aided and abet- ted illegal firearms sales. Held: Because Mexico’s complaint does not plausibly allege that the de- fendant gun manufacturers aided and abetted gun dealers’ unlawful s