OAKLAND — California Attorney General Rob Bonta and a coalition of 19 attorneys general filed an amicus brief in the U.S. Supreme Court on October 28, 2026. The filing supports assault weapon restrictions in Viramontes v. County of Cook.

The brief urges the U.S. Supreme Court to uphold appellate court rulings affirming that the challenged assault weapon laws are consistent with the Second Amendment. It supports laws enacted in Connecticut and Cook County, Illinois, that restrict the sale, manufacture, and possession of certain assault rifles.

The brief argues that the AR-15 platform and similar semiautomatic rifles are uniquely dangerous because their features facilitate assaultive mass killing and are poorly designed for self-defense purposes. It also urges the Supreme Court to reject the argument that the Second Amendment prohibits laws restricting any weapon once it has reached an arbitrary popularity threshold.

"Assault weapon laws restrict a small and uniquely dangerous category of weapons that have proven to be mass shooters’ weapon of choice for a reason," said Attorney General Rob Bonta. "A mass shooter with an assault weapon demonstrably can inflict more deaths and injuries compared to those using other weapons, and three-quarters of mass shootings of 10 or more victims from 2012 to 2022 involved the use of an assault weapon."

The coalition filing the brief includes the attorneys general of Arizona, Colorado, Delaware, the District of Columbia, Hawaii, Illinois, Maine, Maryland, Massachusetts, Michigan, Minnesota, New Jersey, New Mexico, New York, Oregon, Rhode Island, Vermont, and Washington. California’s mass shooting victimization rate for 2023-2025 was 38% below the rest of the U.S. average.

"California enacted the nation’s first state-level assault weapons restriction almost four decades ago to protect our residents from uniquely dangerous weapons with battlefield features that facilitate indiscriminate mass killing," said Bonta.

Ten other states and several cities generally restrict the sale, manufacture, and possession of assault rifles, including the AK-47 and AR-15.