JEFFERSON CITY — Missouri Attorney General Catherine Hanaway, joined by plaintiff Dave Marshak, filed a lawsuit Tuesday against the Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF), seeking to strike down federal registration requirements for suppressors and short-barreled rifles.

The lawsuit argues that federal restrictions on suppressors and short-barreled rifles are unconstitutional because the items qualify as protected arms under the Second Amendment. The complaint cites the U.S. Supreme Court’s ruling in District of Columbia v. Heller, which affirmed an individual right to keep and bear arms for self-defense, and argues that, consistent with the framework the court later laid out in New York State Rifle & Pistol Association v. Bruen, there is no historical tradition in the United States of requiring citizens to register protected firearms. The complaint further contends that suppressors and short-barreled rifles are commonly used for lawful purposes, including hunting, safer firearms training, and self-defense.

“Law and order and the Second Amendment go hand in hand,” Hanaway said in a statement. “A government that respects the Constitution has empowered, law-abiding citizens who can protect themselves and their families. It does not paper over rights with red tape. The ATF’s heavy-handed restrictions on suppressors threaten lawful firearm use and undermine the rights protected by the Second Amendment.”

The lawsuit argues that when Congress reduced the making and transfer taxes under the National Firearms Act to zero for suppressors, short-barreled rifles, and short-barreled shotguns, it undercut the law’s original constitutional basis as a tax measure. Despite that change, Hanaway’s office argues, the federal government continues to enforce extensive registration and data-collection requirements, backed by criminal penalties, that Missouri contends no longer have a valid constitutional justification.

Missouri is asking the U.S. District Court for the Eastern District of Missouri to declare that the federal law’s registration requirements for those untaxed firearms exceed Congress’s constitutional authority and violate the Second Amendment as applied to suppressors and short-barreled rifles. The state is also asking the court to block the ATF and the U.S. Department of Justice from enforcing those provisions and related regulations.