Gun-Control Groups Flooding Supreme Court With Briefs In Big Semi-Auto Case. Here’s What They Are Saying.

Over 40 briefs swamped the Supreme Court Wednesday as part of a case on modern semiautomatic firearms, with one claiming the popularity of the rifles was due to “unlawful marketing.”

In briefs filed on Oct. 21, Connecticut and Cook County cited prohibitions on obscure weapons like launcegays and slungshots while arguing the justices should allow their bans on so-called “assault weapons” to remain in force. The briefs in the case, Viramontes v. Cook County, came from religious organizations, anti-Second Amendment groups, states controlled by Democrats, historians, ballistics experts and survivors of mass shootings, some of which accused firearms companies of boosting the popularity of AR-15s through various forms of “unlawful behavior” in their advertising.

“As the Parkland survivors and families know all too well, AR-15s and other similar weapons can be used to carry out mass shootings,” a brief filed by survivors of the Feb. 14, 2018, mass shooting at Marjory Stoneman Douglas High School in Parkland, Florida, claimed. “There is no evidence that, at the time the Second Amendment was drafted, any firearms could be used to carry out mass shootings.”

“The unprecedented change in technology that allowed for the creation of modern assault weapons has created equally unprecedented societal concerns,” the brief added. “As a result, the Court should conclude that there is no constitutionally protected right to possess AR-15-style assault rifles.”

Another legal brief, filed by social scientists, targeted the 2026 National Firearms Survey conducted by Georgetown University professor William English. The study estimated that Americans owned over 460 million firearms, including 60 million modern semiautomatic rifles and 539 million detachable magazines holding more than ten rounds.

“The English Surveys fail to establish that AR-15-style rifles are ‘commonly used’ in the sense contemplated by the Second Amendment,” the scholars, who included prominent advocates of gun control, including Harvard scholars Deborah Azrael and Professor David Hemenway, claimed. “‘Common use’ is not judged merely by a present-day snapshot; the question is whether an arm has proven itself, across time, to be the sort of weapon ordinary citizens actually rely upon for lawful purposes, such as self-defense.”

Other briefs included one from marketing experts, who claimed the popularity of AR-15-style firearms was due to “unlawful marketing” in the form of “a systematic, widespread pattern of deceptive, unfair and otherwise unlawful tactics, including encouraging illegal conduct.”

“This unlawful behavior should not be ignored or rewarded: no one—including the manufacturers and sellers of assault weapons—should benefit from their own wrongdoing,” the marketers asserted.

In another brief, multiple cities, including Chicago, Los Angeles, Baltimore, Seattle, San Francisco and Boston claimed that modern semiautomatic long guns like the AR-15 were responsible for murders and other violent crimes.