Attorney General Matthew J. Platkin and Massachusetts Attorney General Andrea Joy Campbell announced today that they co-led a coalition of 15 other attorneys general in supporting the state of California’s efforts to restrict the capacity of large-capacity magazines (LCMs) within its borders. The coalition filed an amicus brief Tuesday in support of California in the U.S. Court of Appeals for the Ninth Circuit, arguing that California’s prohibition on the possession and sale of LCMs is consistent with the Second Amendment to the Constitution.

The case, Duncan vs. Bonta, concerns the constitutionality of a California law that allows for possession and sale of firearms magazines that accept up to ten rounds of ammunition, but prohibits LCMs. The U.S. District Court for the Southern District of California misapplied the framework set forth in Bruen and issued a preliminary injunction against California’s LCM ban, and California appealed the decision. The Ninth Circuit has stayed the lower court’s preliminary injunction while it considers California’s appeal, allowing the law to remain in effect for now.

“States have the constitutional right to enact common-sense gun restrictions to protect the public,” said Attorney General Platkin. “Large-capacity magazines are best understood as accessories to firearms and were designed for military use to hold as many bullets as possible. These devices are commonly used in mass shooting incidents across the United States—not for self-defense.”

“The brief outlines how California’s law is consistent with past history and aligns with the Second Amendment:

• To encourage public safety, states can and do impose restrictions on dangerous weapons, accessories, and ammunition that pose a threat to communities: States have widely adopted reasonable restrictions on the public carry, possession, and sale of many types of weapons, accessories, and forms of ammunition that are not suitable for self-defense and undermine the public’s safety. These restrictions are intended to reduce injuries and deaths, while leaving many other options available for individuals who wish to exercise the core Second Amendment right to self-defense.

• LCMs are not protected by the Second Amendment because they are not “arms,” and they are not commonly used or suitable for self-defense: The Second Amendment protects only firearms that are commonly used or suitable for self-defense. LCMs are neither. Instead, they cause an increase in the number and severity of injuries as well as more deaths when used in mass shootings and other forms of gun violence.

• California’s law is consistent with a historical tradition of regulating and imposing restrictions on new and distinctively dangerous forms of weaponry: Historical gunpowder storage laws and other rules and regulations were explicitly intended to prevent threats to public safety by limiting the aggregation of arsenals far beyond what would be sufficient for self-defense. Many state and federal laws throughout American history have also regulated specific dangerous weapons or accessories used for criminal and other violent purposes, such as machine guns or short-barreled shotguns.”

In addition to New Jersey and Massachusetts, the brief was joined by the attorneys general of Arizona, Colorado, Connecticut, Delaware, the District of Columbia, Hawaii, Illinois, Maine, Maryland, Michigan, Minnesota, Oregon, New York, Pennsylvania, Rhode Island, Vermont, Washington, and Wisconsin.