Colorado Gun-Law Suits Mark Aggressive DOJ Bid to Split Circuits

The Trump administration’s two lawsuits challenging firearms regulations in Colorado are emblematic of an aggressive new gun-rights posture at the Justice Department, fueled by attorneys who have long advocated against gun restrictions.

The suits, filed last week, challenge Denver’s decades-old assault-style weapons ban and a Colorado magazine-capacity law enacted in the wake of the 2012 Aurora movie theater shooting that killed 12 people.

The Civil Rights Division has also sued Los Angeles, the US Virgin Islands, and Washington, DC, over what it claims are Second Amendment violations.

But filing in US District Court for the District of Colorado was likely a strategic choice, attorneys said. Colorado is the rare state that has such restrictions on the books but no federal appellate case law explicitly condoning them. A case in the jurisdiction of the relatively moderate Tenth Circuit Court of Appeals could improve the chances of an eventual appellate split that persuades the Supreme Court to take up the matter.

Assault-style weapons — such as the AR-15 — and high-capacity magazines are the subject of one of the hottest Second Amendment legal disputes. Advocates say the firearms are extremely popular and used by law-abiding citizens; opponents call them the weapon of choice for deadly mass shooters.

DOJ declined to comment for this story. In an interview with Just the News touting the Denver lawsuit, Civil Rights Division head Harmeet Dhillon said the bans are “low-hanging fruit” that she anticipates the Supreme Court will overturn.

But those bans have been widely upheld even by appellate judges “who no one would consider to be radical progressives,” said Shira Feldman of Brady United Against Gun Violence.

Gun-rights advocates are looking toward the newly right-leaning Third Circuit to potentially create a circuit split. That court heard oral arguments en banc last year on New Jersey’s restrictions but hasn’t yet released a decision.

Filing in Colorado is likely “a strategic effort on the government’s part to involve one of the more moderate circuits in the debate,” said Hayley Lawrence of the Duke Center for Firearms Law.

Kostas Moros of the Second Amendment Foundation isn’t certain the Tenth Circuit would strike down a ban, but said it’s worth a try.

“DOJ has a fighting chance of getting a good ruling here,” he said. “I wouldn’t take it as a given, though.”

A Gun-Rights Champion

Donald Trump’s administration has brought on multiple attorneys who have long fought against gun restrictions from positions outside the government. That includes Dhillon, who represented the National Association for Gun Rights as amicus in New York State Rifle & Pistol Ass’n v. Bruen, which resulted in a 2022 Supreme Court decision that established a new test for Second Amendment cases. NAGR’s co-founder, David Warrington, is now White House counsel.

DOJ’s Denver and Colorado complaints were both signed by Barry Arrington, former chief legal counsel at NAGR who spent years challenging gun restrictions on behalf of private clients, including in Colorado. Since joining DOJ’s new Second Amendment Section this year, he has the full force of the federal government behind him.

“We’re over the moon about it,” said Hannah Hill, vice president of NAGR’s legal arm. Having DOJ show up for the group’s cause, she said, “feels like the cavalry has arrived.”

DOJ declined to make Arrington available for an interview.

NAGR describes itself as “accepting NO COMPROMISE on the issue of gun control” and positions itself as more hard-line than groups like the National Rifle Association.

Having people with close ties to that group at the top of the administration is deeply troubling, advocates for gun restrictions said.

“They have looked to some of the most extreme organizations, and some of the folks within these organizations, and put them in powerful positions in government,” said Adam Skaggs of Giffords Law Center. “What’s at risk here is the ability of states to take meaningful action to try and combat gun violence.”

DOJ’s recent Second Amendment suits were brought under a federal law passed in the wake of the Rodney King beating and intended to help the government “root out problematic discriminatory policing practices,” Feldman said.

The suits are a “perverse” use of that statute and of the Civil Rights Division, which “was supposed to root out and address invidious racism, police brutality, systemic problems that were really rooted in complicated things about this country’s history,” Feldman said.

Arrington has a history of filing Second Amendment suits in Colorado on behalf of private groups, including one complaint challenging the same magazine restriction he’s now targeting on behalf of DOJ. That suit was later withdrawn.

“He’s had a lot of successful lawsuits, but I think this was sort of unfinished business for him in Colorado,” said Moros, who knows Arrington professionally. While it’s likely DOJ chose the state as a venue because of the Tenth Circuit, Moros said, “I’m sure Barry was very happy that he got to try and go finish this work.”

Arrington also brought a 2022 complaint against assault weapons and magazine bans in multiple Colorado municipalities, which is still pending. He withdrew from representing the gun-rights plaintiffs in March; signing on around the same time was an attorney at Dhillon Law Group, which Dhillon founded before she left to join the Trump administration.

Arrington “jumped into a trench with us” after Bruen, NAGR’s Hill said.

“He started the fight here, and that’s where he really learned the ins and outs of how to effectively fight against a gun ban,” she said. Bringing that experience to a gun-rights-friendly DOJ, she said, is “really the man meeting the moment right now.”

Everytown Law represents the Colorado municipalities in the 2022 lawsuit challenging gun restrictions. Everytown for Gun Safety, which advocates gun-safety measures, is backed by Michael Bloomberg. Bloomberg Law is operated by entities controlled by Michael Bloomberg.

The cases are United States v. City and County of Denver, D. Colo., No. 1:26-cv-01929 and United States v. State of Colorado, D. Colo., No. 1:26-cv-01950.