On Nov. 12, 2019, the U.S. Supreme Court denied certiorari in a case commenced against Remington Arms Co. entities and others by family members of victims of the 2012 Sandy Hook Elementary School massacre in Newtown, Connecticut, which left 20 children and six adults dead. Review was sought by the gun manufacturer following the divided opinion of the Supreme Court of Connecticut in Soto v Bushmaster Firearms International, LLC., 331 Conn. 53, 202 A3d 262 (March 19, 2019), which rejected the defendants' contention that the suit was preempted by the federal Protection of Lawful Commerce in Arms Act, 15 USC 7901-7903. That legislation immunizes firearm manufacturers, distributors and dealers from civil liability for criminal use of firearms by third parties, but provides exceptions including when the manufacturer or seller "knowingly violated a State or Federal statute applicable to the sale or marketing of the [firearm], and the violation was a proximate cause of the harm for which relief is sought…".

The Connecticut Supreme Court (which agreed with the defendants on most issues) permitted the case to proceed on "one narrow legal theory" because of what the majority called "the traditional authority" of states to regulate "advertising that threatens the public's health, safety and morals" which "has long been considered a core exercise of the state's police powers." The majority opinion further concluded that plaintiffs' pleadings were "sufficient to survive a motion to strike" and plaintiffs were "entitled to have the opportunity to prove the wrongful marketing allegations" under state law. Specifically, plaintiffs alleged that the "defendants knowingly marketed, advertised, and promoted the XM15-E2S for civilians to use to carry out offensive, military style combat missions against their perceived enemies" and that such use of the weapon "would be illegal" in Connecticut because state law "does not permit advertisements that promote or encourage violent, criminal behavior." Moreover, the federal act did not clearly manifest "an intent to extinguish the traditional authority" of states to protect its citizens "from the pernicious practices" as alleged by plaintiffs.

Thus, the Connecticut Supreme Court held that the federal act did not preempt generally applicable state statutes such as the Connecticut Unfair Trade Practices Act, which prohibits "unfair and deceptive acts or practices in the conduct of any trade or commerce," including unethical advertising of dangerous weapons for illegal purposes, and that Congress "failed to effectively express" an intent "to broadly immunize firearms sellers from liability for the sort of egregious misconduct the plaintiffs have alleged." According to the majority, the congressional record was simply insufficient on which to conclude it intended "to immunize firearms suppliers who engage in truly unethical and irresponsible marketing practices promoting criminal conduct" so as to preclude state action to address and remedy such wrongful practices.