Nationwide Impact: DOJ’s Gun Law Battle Begins

Black rifles on a dark fabric background

The Trump administration’s Department of Justice has filed federal lawsuits challenging Denver’s 37-year-old assault weapons ban and Colorado’s large-capacity magazine restriction, marking an aggressive enforcement of Second Amendment protections that signals a nationwide campaign against local gun control measures.

Quick Take

DOJ filed separate lawsuits on May 5-6, 2026, against Denver and Colorado, arguing their bans violate the Second Amendment under precedents established in Heller and Bruen
Denver Mayor Mike Johnston and city officials refused a prior DOJ demand to repeal the ban, calling it “federal overreach” and vowing vigorous defense
The litigation represents the first cases under a new Second Amendment Section within the DOJ’s Civil Rights Division, part of a broader Trump administration campaign
Gun rights advocates argue the bans fail constitutional scrutiny because AR-15-style rifles are “in common use” for lawful purposes, with tens of millions owned nationwide

Federal Action Targets Local Gun Restrictions

The Department of Justice, under Acting Attorney General Todd Blanche and Civil Rights Division Assistant Attorney General Harmeet Dhillon, filed United States v. Denver on May 5, 2026, challenging the city’s prohibition on semi-automatic rifles with certain features and magazines exceeding 15 rounds. The following day, DOJ filed United States v. Colorado, targeting the state’s 2013 large-capacity magazine ban. Both suits seek permanent injunctions, arguing these restrictions violate the Second Amendment as applied to arms “in common use” for lawful self-defense purposes.

Denver’s ordinance, enacted in 1989, represents one of the oldest municipal assault weapons bans in the nation, predating the federal Assault Weapons Ban (1994-2004). Colorado’s magazine restriction followed the 2012 Aurora theater shooting and 2012 Sandy Hook Elementary shooting. City Attorney Miko Brown contends the DOJ misapplies federal statute 34 U.S.C. §12601, designed for police misconduct cases, to challenge local ordinances. Despite these objections, the suits proceed in U.S. District Court for the District of Colorado.

Constitutional Arguments Center on “Common Use” Standard

The DOJ’s legal strategy relies heavily on the Supreme Court’s 2022 decision in New York State Rifle & Pistol Association v. Bruen, which established a history-and-tradition test for evaluating gun regulations. The government argues Denver and Colorado cannot meet this standard because no historical tradition supports banning popular semi-automatic rifles. The AR-15, DOJ contends, is the most popular rifle in America, with tens of millions in civilian hands, making bans constitutionally indefensible under the “common use” framework established in District of Columbia v. Heller (2008).

Dhillon stated that no historical analog exists for banning the most popular rifle in the nation for lawful self-defense. The DOJ rejects “assault weapon” as a technical classification, characterizing it instead as political terminology used to circumvent constitutional protections. This framing distinguishes the federal position from lower courts, where six appellate courts have upheld similar bans post-Bruen, creating a split that may invite Supreme Court review.

Denver Stands Firm Amid Federal Pressure

Mayor Mike Johnston rejected the DOJ’s late April demand letter, publicly declaring “Hell no” to federal pressure and characterizing the demand as federal overreach. Johnston emphasized that Denver’s 37-year ban reflects community values and public safety priorities. City officials vowed vigorous defense, citing the ban’s longevity and the city’s commitment to preventing gun violence. Gun control advocates argue the restrictions have proven effective, pointing to Denver’s experience and the broader public health rationale for limiting access to high-capacity magazines and semi-automatic rifles.

The city’s resistance reflects broader tensions between local autonomy and federal authority. Denver’s Democratic leadership, aligned with urban gun control advocates, contrasts sharply with Colorado’s rural gun culture and Republican-leaning areas. This geographic and political split within Colorado complicates the state’s position as a defendant in the magazine ban litigation, creating internal pressure as the Trump administration escalates its Second Amendment enforcement agenda.

Broader Campaign Signals National Shift

The Denver and Colorado suits represent the first cases filed under the DOJ’s newly established Second Amendment Section within the Civil Rights Division, launched in 2025. The Trump administration previously sued Washington, D.C., over its assault weapons ban, establishing a template for challenging similar restrictions nationwide. Legal experts note that approximately 20 states and cities maintain comparable bans, making these cases potentially precedent-setting for a nationwide litigation campaign.

Gun rights organizations, including the NRA-ILA and Colorado State Shooting Association, have pledged support for the DOJ’s legal positions. Short-term implications include potential court injunctions halting enforcement, which would allow possession and sales of currently banned weapons in Denver and Colorado. Long-term outcomes could reshape gun regulations across the country if courts uphold the DOJ’s constitutional arguments or if the Supreme Court grants review, fundamentally altering the post-Bruen legal landscape.