From Justice Kagan's unanimous (and, I think, correct) opinion today in Smith & Wesson Brands, Inc. v. Estados Unidos Mexicanos:
The Government of Mexico brought this lawsuit against seven American gun manufacturers. As required by a federal statute, Mexico seeks to show (among other things) that the defendant companies participated in the unlawful sale or marketing of firearms. See [Protection of Lawful Commerce in Arms Act,] 15 U.S.C. §7903(5)(A)(iii). More specifically, Mexico alleges that the companies aided and abetted unlawful sales routing guns to Mexican drug cartels. The question presented is whether Mexico's complaint plausibly pleads that conduct. We conclude it does not….
[T]his Court has developed several … principles [defining aiding and abetting law]. First, aiding and abetting is most commonly "a rule of secondary liability for specific wrongful acts." It is possible for someone to aid and abet a broad category of misconduct, but then his participation must be correspondingly "pervasive, systemic, and culpable."
Second, aiding and abetting usually requires misfeasance rather than nonfeasance. Absent an "independent duty to act," a person's "failure[s]," "omissions," or "inactions"—even if in some sense blameworthy—will rarely support aiding-and-abetting liability.
And third, routine and general activity that happens on occasion to assist in a crime—in essence, "incidentally"—is unlikely to count as aiding and abetting. So, for example, an "ordinary merchant[]" does not "become liable" for all criminal "misuse[s] of [his] goods," even if he knows that in some fraction of cases misuse will occur. The merchant becomes liable only if, beyond providing the good on the open market, he takes steps to "promote" the resulting crime and "make it his own."
