The Wire · CalGunHub

California Joins 18 States in Supreme Court Brief Defending Semiautomatic Rifle Bans

Published October 31, 2026 · Updated October 31, 2026

Attorney General Rob Bonta and a coalition of state officials are urging the Supreme Court to uphold firearm restrictions from Illinois and Connecticut.

Written by the CalGunHub desk from public reporting

Who this affects: The Supreme Court's upcoming decision in this consolidated case could establish a nationwide precedent regarding state-level bans on specific semiautomatic rifles. If the justices rule against Cook County and Connecticut, similar restrictions in California might face renewed legal challenges or be invalidated. Conversely, a ruling that upholds the local ordinances would likely reinforce the legal standing of California's existing firearm regulations.

On October 28, 2026, California Attorney General Rob Bonta joined a coalition of 18 other attorneys general to file a brief with the United States Supreme Court supporting firearm restrictions in Illinois and Connecticut.

According to Law News UK, the amicus brief was submitted in the case Viramontes v. County of Cook (docket No. 25-238). The state officials are asking the justices to affirm lower court decisions that upheld bans on specific semiautomatic rifles. The coalition argues that these regulations fit within the historical tradition of the Second Amendment because the targeted firearms are exceptionally lethal.

The filing asserts that platforms like the AR-15 are engineered for mass casualties rather than self-defense. The attorneys general also push back against the idea that a firearm becomes immune to regulation simply by reaching a certain level of commercial popularity. They claim such a standard would incentivize manufacturers to saturate the market with new designs before lawmakers could respond.

To support their position, the brief cites data indicating that 75 percent of mass shootings resulting in 20 or more deaths between 1991 and 2022 involved the restricted firearms. Bonta stated that these laws target a specific category of firearms that are "mass shooters' weapon of choice for a reason."

The Supreme Court previously merged the related challenges on June 30, 2026. Petitioners submitted their primary arguments on August 28, 2026. Following a rejection of their initial October 21, 2026 filings, respondents from Cook County provided their corrected documents on October 27, 2026. The federal Solicitor General has also requested permission to participate in the upcoming oral arguments.

Informational only, not legal advice. Facts are attributed to the sources listed above.