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Defending the City of Boulder, Colorado Against Legal Challenge to the City’s Restrictions on Assault Weapons, Large-Capacity Magazines, and the Possession of Firearms by those Under 21

Caldara, et al. v. City of Boulder, et al.


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Boulder, CO – Everytown Law is representing the City of Boulder, Colorado in a legal challenge to the City’s gun-safety ordinance, enacted in 2018, which includes prohibitions on the possession and sale of assault weapons and large-capacity magazines in the City and strengthens restrictions on the possession of firearms by minors under the age of 21.

Plaintiffs–two individuals, a gun dealer, and a shooting club–filed a lawsuit against the City the day after the ordinance was passed and, a month later, filed a motion in an effort to prevent the City from enforcing the ordinance while their lawsuit is ongoing. On September 17, 2018, agreeing with the arguments made by the City, the federal district court decided that it would abstain from deciding any of the plaintiffs’ Second Amendment and other federal constitutional claims until a state court decided whether the ordinance was preempted under state law. On April 10, 2020, the United States Court of Appeals for the Tenth Circuit affirmed, and the U.S. Supreme Court subsequently denied certiorari review. Everytown Law is co-counsel in this litigation with Arnold & Porter Kaye Scholer LLP, the Boulder City Attorney’s Office, and the Giffords Law Center to Prevent Gun Violence.

In a related state-court lawsuit, a separate set of plaintiffs–backed by the National Rifle Association and initially including the NRA’s Colorado state affiliate–challenged the Boulder ordinance under Colorado’s preemption law. On March 12, 2021, a state district court judge sided with the plaintiffs, blocking enforcement of the provisions of the ordinance prohibiting assault weapons and large-capacity magazines on state preemption grounds. Since that time, the assault weapons and large-capacity magazine provisions of Boulder’s ordinance have not been in effect.

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