Supreme Court Decides Smith & Wesson Brands, Inc. v. Estados Unidos Mexicanos

On June 5, 2025, the Supreme Court of the United States decided Smith & Wesson Brands, Inc. v. Estados Unidos Mexicanos, No. 23-1141, holding that the Protection of Lawful Commerce in Arms Act (PLCAA) barred Mexico’s lawsuit against American gun manufacturers, including Smith & Wesson Brands, Inc.

The case arose under the PLCAA, which generally bars lawsuits against gun manufacturers from being brought in any state or federal court. The PLCAA has an exception, and allows lawsuits against American gun manufacturers if they “knowingly violated a State or Federal statute applicable to the sale or marketing” of firearms, and that “violation was a proximate cause of the harm for which relief is sought.”

Here, the Government of Mexico sued seven American gun manufacturers, alleging that the companies aided and abetted unlawful gun sales that illegally routed firearms to Mexican drug cartels. Mexico argued that the gun manufacturers were responsible for harms that flow from the weapons’ misuse. Specifically, Mexico alleged that the manufacturers: (i) supplied firearms to retailers who they know illegally sell guns to Mexican gun traffickers; (ii) failed to establish controls that would prevent illegal sales; and (iii) make “design and marketing decisions” that stimulate cartel demand for guns.

The District Court dismissed the complaint as not qualifying for the PLCAA exception. But the First Circuit reversed, holding that Mexico had plausibly alleged that defendants aided and abetted illegal firearm sales.

The Supreme Court reversed, concluding that Mexico’s complaint did not plausibly allege the kind of “conscious … and culpable participation in another’s wrongdoing” needed to make out an aiding and abetting charge. Three principles further informed the Court’s decision.

First, aiding and abetting commonly applies to specific wrongful acts; broader liability is possible, but only if a wrongdoer’s participating is correspondingly pervasive and systemic. Here, the gun manufacturers’ conduct did not qualify.

Second, aiding and abetting usually requires an act, rather than failure to act. Mexico alleged only a failure to act, so it did not plausibly allege aiding and abetting liability.

And third, routine activity that incidentally assists crime is unlikely to, without more, count as aiding and abetting. There too, all Mexico alleged was that gun manufacturers incidentally assisted criminals through routine activity.

Therefore, the Court held that Mexico had failed to plausibly allege that American gun manufacturers had aided and abetted unlawful sales routing guns to Mexican drug cartels. For that reason, Mexico’s claims did not qualify for the exception where a seller “knowingly violated a State or Federal statute 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).

Justice Kagan delivered the opinion for a unanimous Court. Justices Thomas and Jackson filed concurring opinions.