When Nations Sue: The Legal Architecture of Mexico’s Firearms Litigation in U.S. Courts
When one nation has a serious grievance with another and it decides that the best course of action is the legal route, we tend to see a case resolved in the Netherlands, specifically at the United Nations’ International Court of Justice. We don’t often see foreign countries participate in our legal system, and when they do, it’s through amicus briefs. It would seem unusual, almost unthinkable, for another country to seek redress through United States legal channels rather than diplomatic ones.
However, far from the Netherlands, the Mexican government sued seven American gun manufacturers in a Massachusetts District Court in 2021 (1). The lawsuit accused gun manufacturers of facilitating the flow of arms into Mexico, alleging that 70% of traceable arms in Mexico come from the United States, accusing gun manufacturers of facilitating the illicit acquisition of arms by the cartels. American legal experts questioned the possibility of the case being successful; some pointing out problems in the lawsuit’s jurisdiction, and others calling it a ploy to get the White House’s attention.
Unsurprisingly, the case was dismissed (2). While the Massachusetts court agreed that most weapons in Mexico are from America, most of those come from the states bordering Mexico. The court’s decision details how the Protection of Lawful Commerce in Arms Act (PLCAA), a piece of legislation protecting the firearm industry from liability for the criminal misuse of their products, bars lawsuits holding gun manufacturers accountable. Mexico’s attorneys had not sufficiently proved that the gun manufacturers were aiding and abetting the sale of illicit firearms. However, the First Circuit Court of Appeals sided with Mexico on appeal, finding that Mexico’s case had met one of the few exceptions in the PLCAA, a requirement proving causality (3).
The appeal allowed for the case to be heard by the Supreme Court, and in July 2025, the Court concluded that Mexico had failed to meet the requirements for aiding and abetting, unanimously reversing the appellate court’s decision (4). The Supreme Court’s decision seemingly put an end to the saga of a very confusing lawsuit littered with glaring problems.
Mexico’s lawsuit had three main issues. Firstly, the country was suing gun manufacturers for problems pertaining to distribution. To prove that these companies had any intentional control over their product multiple steps past the manufacturing stage seems almost impossible, and any attempt to prove “aiding and abetting” clearly fell short. Secondly, the PLCAA has very strict exceptions, with the text also having a focus on distribution rather than manufacturing. The main exception used in the lawsuit states that the defendant must have “knowingly violated a State or Federal statute applicable to the sale or marketing,” which as we’ve established, would be difficult to prove if you’re suing manufacturers. Finally, the choice to sue in Massachusetts is, to say the least, confusing. While it might initially seem that Mexico chose a court in this state as they thought that it might have been friendlier to them, it simply served to make jurisdiction harder to argue.
However, the Supreme Court’s decision does not mark the end of this story. Mexico had submitted another lawsuit in Arizona against five gun distributors in 2022 (5). This case is ongoing and currently in the discovery/evidence production stage. Looking at the Mexican government’s field briefs, which were convoluted in Massachusetts but are coherent in Arizona, it seems as though the failed lawsuit that made its way up to the Supreme Court in 2025 was a “test run” for a more successful one.
The Arizona case “fixes” the mistakes made in the Massachusetts one. After compelling the Massachusetts court to agree that most weapons come from the area Arizona finds itself in, Mexico’s lawyers are able to more succinctly make an argument for jurisdiction. Additionally, this second lawsuit is against the distributors, thus addressing the problem more directly.
While the Arizona case does a remarkable job at succeeding where the Massachusetts one failed, the great challenge for Mexico’s lawyers is now to argue that the PLCAA allows them to sue in the first place. To prove beyond reasonable doubt that a firearm distributor “knowingly violated a State or Federal statute applicable to the sale or marketing” is still an extraordinary task. This notion is only further confirmed given that the case has been in the early stages of litigation for three years, with the current stage of evidence production taking up most of that time.
Most cases pertaining to the PLCAA challenge its constitutionality, rather than attempt to fit an exemption (6;7). This greatly complicates things for Mexico. If the Arizona case were to make it to the Supreme Court, the Court would, ironically, probably use the Massachusetts one as their main example when looking at precedent. The extraordinary task of meeting any PLCAA exemption both explains why cases usually (unsuccessfully) opt to challenge its constitutionality over arguing within the act’s confines, and spells a dour outcome for Mexico’s second attempt.
If, as some legal experts speculated back in 2021, this was all a plot to get the attention of the White House, it certainly failed, given that the second lawsuit is still ongoing and the Mexican government has clear intentions to invest more resources into it. Both cases, whether the second one succeeds in court or not, will have repercussions on how Mexico and the United States conduct their diplomatic relations. These are landmark cases of foreign nations suing American entities on American soil, and could signal to other countries that this is an avenue for relief or political gain.
Published March 4, 2026 By Alex Ellis
Natalie Kitroeff and Oscar Lopez, “México demanda a empresas de armas en EE. UU.; las acusa de avivar la violencia,” The New York Times, August 4, 2021, https://www.nytimes.com/es/2021/08/04/espanol/mexico-demanda-fabricantes-armas.html
Estados Unidos Mexicanos v. Smith & Wesson Brands, Inc. et al., No. 21-11269-FDS, United States District Court of Massachusetts, (Sept. 30, 2022), https://tlblog.org/wp-content/uploads/2022/09/Mexico.OpinionMTD.pdf
León Castellanos-Jankiewicz, “La Suprema Corte estadounidense falla a favor de armerías ante la demanda de México, pero les niega inmunidad total,” Just Security, June 23, 2025, https://www.justsecurity.org/115977/suprema-corte-estadounidense-demanda-mexico/
Smith & Wesson Brands, Inc. v. Estados Unidos Mexicanos, No. 23-1141, Supreme Court of the United States, (June 5, 2025), https://supreme.justia.com/cases/federal/us/605/23-1141/
Estados Unidos Mexicanos v. Diamondback Shooting Sports Incorporated et al, No. 4:22-cv-00472-JR, United States District Court of Arizona, (Oct. 10, 2022), https://portales.sre.gob.mx/acervo/images/Litigio_armas/Demanda_de_Arizona/Estados_Unidos_Mexicanos_vsDiamond_Back_Shooting_Sports_et_al.pdf
National Shooting Sports Foundation, Inc. v. James, No. 22-1374, United States Court of Appeals Second Circuit, (July 10, 2025), https://law.justia.com/cases/federal/appellate-courts/ca2/22-1374/22-1374-2025-07-10.html
Gustafson v. Springfield, Inc., No. J-22-2024, Supreme Court of Pennsylvania, (March 31, 2025), https://law.justia.com/cases/pennsylvania/supreme-court/2025/7-wap-2023.html