A group of 12 states and the District of Columbia signed on to support a California prohibition on magazines capable of holding 10 or more cartridges.

In response to a federal lawsuit by several California residents in conjunction with the state’s National Rifle Association affiliate who argue the state’s prohibition against “high-capacity magazines” violates their Second Amendment rights, Washington D.C. Attorney General Karl A. Racine and attorneys general from a dozen other states are siding with California.

“The Supreme Court has been clear that the Second Amendment is not a blank check allowing the use of any kind of gun at any time or in any fashion,” Racine said in a statement from his office. “States like California are within their rights to enact reasonable gun laws, and courts shouldn’t overrule sensible, evidence-based policy decisions that enhance public safety and can save lives.”

In 2000, California passed a ban on such magazines but still allowed those already in circulation to remain grandfathered. Last year, Gov. Jerry Brown signed a measure making possession of even legacy “pre-ban” magazines illegal, sparking the lawsuit filed in May. This led to an injunction against enforcement of the new law pending a decision in the court which was appealed to U.S. 9th Circuit, filed by California Attorney General Xavier Becerra.

With estimates of more than 100 million magazines capable of holding 10 or more rounds in circulation in the country, and the devices legal in 43 states without regulation, the plaintiffs argue that banning such magazines will have a negligible effect on crime.

Racine, in his 26-page friend of the court brief, contends nothing in the Second Amendment prevents states and the District from enacting gun regulations and the injunction ordered earlier this summer “unnecessarily hobbles California’s ability to enact public safety legislation.”

States signing on to the brief include Connecticut, Delaware, Hawaii, Illinois, Iowa, Maryland, Massachusetts, New York, Oregon, Rhode Island, Virginia, and Washington. Notably, while several of the signatory states do not currently have bans or limits on magazine capacity, the supporters say they agree with California’s stand “not because they necessarily believe that California’s policy approach would be optimal for them, but to underscore that the challenged law represents a policy choice that California is constitutionally free to adopt.”

Meanwhile, California Lt. Gov. Gavin Newsom, teamed up with the Giffords gun control group, filed a supporting brief of their own last week, citing the follow-on voter initiative, Prop. 63, which reinforced the magazine ban.

“It’s a tragic reality that as time passes, we are presented with more and more evidence on the devastating power of large capacity magazines, which are consistently the accessory of choice in mass shootings for mass murderers,” said Newsom. “Federal courts have repeatedly upheld bans and restrictions on large capacity magazines and I am confident that the court will ultimately rule that Proposition 63’s ban on the possession large capacity magazines is constitutional.”