Gun rights activists on Tuesday sued Gov. Jared Polis, asking a Denver district court to stop enforcement of a 2013 state law that bans the possession of large capacity magazines capable of accepting more than 15 rounds.

The National Foundation for Gun Rights, the legal arm of Rocky Mountain Gun Owners, and two Colorado residents sought a temporary restraining order and a permanent injunction against the gun law.

The lawsuit followed the June 23 U.S. Supreme Court decision in New York State Rifle & Pistol Association v. Bruen, which overturned  New York state’s and New York City’s handgun licensing systems.

Taylor Rhodes, RMGO’s executive director, said that decision opened the door to federal lawsuits challenging other state and local gun laws.

The Governor’s Office maintains that Bruen won’t affect gun laws in Colorado.

“This decision should not impact any of Colorado’s statewide gun safety laws because Colorado state law does not contain ‘proper cause’ requirements for concealed carry permits, which was the focus of the Supreme Court decision,” said Conor Cahill, the governor’s spokesman.

When asked whether Denver’s strict gun regulations might be considered unconstitutional under Bruen, Denver Mayor Michael Hancock replied, “We’re confident our regulations are constitutional, but the Supreme Court’s ruling striking down long-standing, responsible and common sense regulations in New York is deeply troubling.”

He added there is “no reason why weapons of war should be available for sale in this country or responsible and legal restrictions on access to guns should be struck down.”

Gun rights advocates disagree with Polis and Hancock, saying many restrictions on gun ownership and carrying guns in public for self protection are now unconstitutional under Bruen.

“We’ve been given the golden ticket to dismantle all of these gun control laws, not only at the local level, but on the state level as well,” Rhodes said. “Rocky Mountain Gun Owners filed the first two lawsuits in post-Bruen America. We’re effectively setting precedent for generations to come, not only in Colorado, but potentially across America.”

“We’ve known for years that the (magazine ban) is an atrocious infringement against our Second Amendment freedoms,” added Dudley Brown, president of Rocky Mountain Gun Owners. “The Bruen decision gave us a 4-ton wrecking ball to dismantle Colorado’s gun control laws – and we’re going to wipe out every unconstitutional law that stands in the way of law-abiding citizen’s Second Amendment rights.”

The Supreme Court held that regulations that condition carrying firearms for self defense on subjective judgments by government bureaucrats or that ban entire categories of firearms violate the U.S. Constitution.

“The constitutional right to bear arms in public for self-defense is not a second-class right, subject to an entirely different body of rules than the other Bill of Rights guarantees,” Justice Clarence Thomas wrote for the majority. “We know of no other constitutional right that an individual may exercise only after demonstrating to government officers some special need … It is not how the Second Amendment works when it comes to public carry for self defense.”

Instead, the court established a new test for constitutionality based in America’s history of arms regulation during the nation’s founding period. If, the court said, the government cannot show that a law is analogous to some historical regulation that would have been allowed at the time of ratification under the Second Amendment, it is unconstitutional.

“The Supreme Court laid out fairly clearly that, when other federal courts were reviewing Second Amendment challenges, they were to look at the text of the Second Amendment and then determine what those words meant when the amendment was ratified in 1791,” said Cody Wisniewski, senior attorney for constitutional litigation at the Firearms Policy Coalition in Las Vegas.

Bruen builds upon a framework of Supreme Court decisions beginning with the 2008 case District of Columbia v. Heller, in which the court said that D.C.’s outright ban on the possession of a handgun in the home violates the Constitution and that the right to keep and bear arms is both an individual right not predicated on militia membership and it applies to state laws through the 14th Amendment’s right to due process.

Attorney David Kopel, director of research at the Independence Institute, a Denver-based libertarian think tank, described Bruen as something of a smack-down of the lower federal courts. He said that, since Heller, courts have been concocting their own versions of a two-part means-ends analysis that weighs the rights of gun owners against the needs of the government to control guns. Kopel is a gun rights expert whose scholarly work has been cited in several U.S. Supreme Court gun cases, including Bruen.

Colorado’s magazine ban law has been previously challenged in state courts by RMGO, resulting in a 2020 ruling by the Colorado Supreme Court upholding the ban.

In its ruling, Kopel said, the state Supreme Court completely ignored Colorado’s state constitutional protection of gun rights, saying instead that the state can regulate firearms under its “inherent police power” so long as the regulation is “reasonably related to a legitimate governmental interest such as the public health, safety or welfare.”

“We reject the contention that U.S. Supreme Court decisions interpreting the Second Amendment to the U.S. Constitution control our analysis,” the state court concluded.

Critics of that decision argue that this disregard for U.S. Supreme Court precedents is likely to result in federal courts overturning such local laws.

Wisniewski argued that ordinances under the state statute authorizing gun regulations and bans by counties and municipalities – including what Rhodes called “tip of the spear” anti-gun jurisdictions pursued by Superior, Boulder, and Denver municipalities – are flatly unconstitutional under Heller and Bruen.”

The RMGO also filed a lawsuit June 7 against the Town of Superior over a new ordinance banning the carrying and possession of firearms, including so-called “assault weapons.” In that case, U.S. District Judge Raymond Moore granted a temporary restraining order July 22 blocking enforcement of the town’s ordinance that will remain in effect until the case is heard in federal court in November.