A Rodney King-era civil rights law drives the federal lawsuit over Colorado’s magazine ban

By Jen Schumann | Rocky Mountain Voice

Colorado’s magazine ban has been challenged before. The surprise this time is not the Second Amendment argument. It is the DOJ’s decision to use a federal civil-rights law traditionally aimed at police misconduct investigations to make it. On May 5, federal attorneys filed against Denver over its assault-weapons ban. The next morning, they were back in court with another complaint—this one against the state, over the 15-round magazine limit.

The law driving both lawsuits came out of the aftermath of Rodney King. Congress passed §12601 in 1994 after Los Angeles erupted in riots, giving the federal government authority to intervene when police departments repeatedly violated constitutional rights. DOJ has used the law fewer than 100 times in the three decades since.

Until this year, never to enforce the Second Amendment. The lawsuits mark a significant expansion in how DOJ is using federal civil-rights authority.

How the DOJ built its case

The DOJ builds its case through the officers who enforce the law. 

Colorado’s magazine ban only works if somebody enforces it. The complaint focuses on State Patrol troopers and CBI agents, who enforce criminal laws across the state, including the 2013 restriction on magazines holding more than 15 rounds.

Under the DOJ’s reading of §12601, the constitutional violation happens through the continued enforcement of the ban itself.

The defendants are the State of Colorado and the Colorado Department of Public Safety. Not Governor Jared Polis. Not Attorney General Phil Weiser. The state troopers and CBI agents doing their jobs.

The complaint asks the court for declaratory judgment that DPS officers’ enforcement of the ban “deprives the people of Colorado of their rights guaranteed by the Second Amendment.” It also asks for a permanent injunction barring enforcement and an order requiring DPS to “adopt and implement policies and procedures to remedy the pattern or practice of unlawful conduct.” 

That language is the structural template of a police consent decree—the same kind of court-supervised reform DOJ once imposed on the LAPD and Baltimore. The DOJ used the phrase explicitly in its April 28 pre-suit letter to Denver, telling the city it could avoid litigation by entering “a court-enforceable consent decree” permanently barring enforcement of the assault weapons ban.

Colorado’s own words as evidence

The factual backbone of the complaint comes from Colorado itself. When the state defended the magazine ban in two prior cases—Colorado Outfitters Association v. Hickenlooper in federal court and Rocky Mountain Gun Owners v. Hickenlooper in state court, both filed in 2013—it formally agreed to a list of facts about firearms and magazine ownership. 

Those facts are now sworn into the court record. The DOJ is using them as the foundation of its new lawsuit.

Among the facts Colorado agreed to: more than 300 million firearms are lawfully owned in the United States. The number of lawfully owned semi-automatic firearms using magazines like those banned by Colorado is “in the tens of millions.” In Colorado alone the number of such magazines is “in the millions.” 

In states without magazine restrictions, AR-15 rifles are commonly sold with 30-round magazines, and many owners use magazines holding 20 or 30 rounds. Colorado also previously acknowledged in court filings that semi-automatic pistols and rifles “cannot function as designed without a magazine.”

The lawsuit also points to a newer estimate from the National Shooting Sports Foundation, which says at least 448 million magazines holding more than 15 rounds are in circulation across the United States.

The DOJ is using Colorado’s own earlier court filings to reinforce that argument. In defending the law years ago, the state acknowledged how widely owned the magazines are across the country and within Colorado itself.

The Supreme Court’s decisions in Heller and Bruen recognized constitutional protections for firearms and related equipment commonly possessed for lawful purposes—the same standard the DOJ says Colorado already acknowledged these magazines meet.

A different kind of civil-rights case

The legal counterpunch came from Denver first. In an April 28 response letter to the DOJ, Denver City Attorney Miko Brown went after the statute itself.

“Your reliance on 34 U.S.C. Section 12601 as a basis for your threatened lawsuit is neither compelling nor proper,” Brown wrote. “Congress enacted Section 12601 in the wake of the horrific Rodney King beating to provide the federal government with tools to combat excessive force and other kinds of misconduct in state and local police departments. Your effort to use Section 12601 to mount a facial challenge to the City’s democratically-enacted Ordinance flies in the face of text, history, and past practice.”

Weiser made the same case after the DOJ sued the state on May 6.

“Using federal civil rights law to put Coloradans at greater risk of gun violence is a dangerous overreach by the Justice Department, and this lawsuit turns the mission of the DOJ’s Civil Rights Division on its head,” Weiser said in a statement.

The lawsuits also offer a glimpse into how the Trump administration is reshaping priorities inside the DOJ’s Civil Rights Division. The department now includes a dedicated Second Amendment Section focused on identifying what it describes as “litigation opportunities” involving gun rights.

“Colorado’s ban on certain magazines is political virtue signaling at the expense of Americans’ constitutional right to keep and bear arms,” Assistant Attorney General Harmeet Dhillon, who leads the Civil Rights Division, said in announcing the suit.

The Colorado lawyer behind the complaints

The complaints against Denver and the state were signed by Barry K. Arrington, Acting Chief of the DOJ’s Second Amendment Section. 

Before joining the Justice Department, Arrington brought a federal lawsuit challenging Colorado’s magazine ban on behalf of the National Foundation for Gun Rights. The case was dismissed in 2024—two years before Arrington signed the DOJ complaint now seeking to block enforcement of the same law.

For more than a year, leaders with Rocky Mountain Gun Owners traveled to Washington, met with DOJ officials and delivered more than 60,000 petitions urging federal action against Colorado’s gun restrictions.

“For years, Denver has treated the Bill of Rights like a suggestion,” said Ian Escalante, Executive Director of RMGO. “They banned commonly owned rifles, threatened peaceful citizens with criminal penalties, and dared gun owners to fight back. Well, now the fight is here. RMGO members helped drag this issue all the way to Washington, D.C., and today the anti-gun politicians in Denver are finally facing consequences.”

When gun rights meet civil-rights enforcement

Colorado’s magazine ban survived a challenge before the state Supreme Court in 2020, but that case turned on Colorado’s constitution—not the federal Second Amendment arguments driving the DOJ lawsuit.

The 10th Circuit has not yet issued a controlling post-Bruen ruling on Colorado’s magazine ban.

For decades, §12601 has been used by the federal government to challenge constitutional violations tied to policing. In Colorado, DOJ is now applying that same civil-rights authority to the enforcement of state gun laws—a significant shift in how the federal government defines constitutional enforcement.