Debates over gun regulation are increasingly being decided through competing readings of U.S. history, especially after the Supreme Court’s 2022 Bruen decision told courts to measure modern laws against the nation’s historical firearms tradition. That national legal fight has narrowed to a new Republican argument that an 18th-century militia statute helps protect ownership of AR-15-style rifles, with Illinois’ assault weapons ban again at the center of the dispute. The issue has drawn attention because House Republicans are using a founding-era law, not only modern policy arguments, to defend one of the country’s most contested firearms.
House Republicans tie AR-15s to a founding-era militia requirement
A group of House Republicans backed a Supreme Court amicus brief in a challenge to Illinois’ assault weapons ban, arguing that AR-15-style rifles are consistent with the type of arms ordinary citizens were expected to possess under early American militia laws. The brief in the Illinois case, known as Harrel v. Raoul, pointed to the Militia Act of 1792, which required many enrolled militia members to equip themselves with a musket, bayonet and ammunition, according to the historical text preserved by the Library of Congress and the National Archives.
The legal argument builds on the framework the Supreme Court set out in New York State Rifle & Pistol Association v. Bruen in June 2022, requiring judges to assess whether modern gun restrictions align with historical tradition. In a later decision, United States v. Rahimi on June 21, 2024, the court said governments may still rely on historical analogies rather than exact founding-era twins, according to Congress.gov’s Constitution Annotated.
Supporters of the brief say that matters because AR-15-style rifles are commonly owned civilian semiautomatic weapons, not automatic military firearms. An amicus brief filed in the Illinois litigation cited an industry estimate of more than 24.4 million modern sporting rifles in circulation nationwide as of 2022, based on National Shooting Sports Foundation data included in the court filing.
The direct state impact is in Illinois, where Governor JB Pritzker signed the Protect Illinois Communities Act on January 10, 2023, banning the sale and distribution of many assault weapons, large-capacity magazines and switches, according to Illinois State Police. The law includes AR-15-style rifles among the firearms covered by the restrictions, and litigation over that law has become one of the highest-profile tests of post-Bruen gun regulation.
What is confirmed is that the Supreme Court declined in July 2024 to immediately take up appeals challenging the Illinois ban, leaving lower-court rulings in place for the time being, according to Reuters. What is not yet known is whether the justices will ultimately hear a future merits case on state assault weapons bans after additional appellate review.
Illinois residents therefore remain under the current state framework unless courts order otherwise. The state has publicly described the law as regulating assault weapons and related devices, but a final nationwide answer on whether bans on AR-15-style rifles survive the Supreme Court’s historical-tradition test has not yet been issued.
The reason lawmakers are reaching back to 1792 is the Supreme Court’s instruction that Second Amendment disputes now turn heavily on history. In Bruen, the justices rejected the balancing tests many lower courts had used for years and directed courts to ask whether a modern firearms restriction is consistent with the country’s historical tradition of regulation. That has pushed both gun-rights advocates and governments to search statutes, practices and commentary from the 18th and 19th centuries.
Republicans’ reliance on the Militia Act of 1792 also reflects a broader argument that firearms in common civilian use deserve constitutional protection. In court papers, supporters of AR-15 ownership have argued that widespread lawful possession matters under the Supreme Court’s earlier Heller decision and remains relevant after Bruen. Opponents of assault weapons bans say the rifles are standard semiautomatic arms; supporters of the bans argue the weapons’ firepower and use in mass shootings justify restrictions.
For residents, the practical takeaway is that this debate is no longer limited to legislatures. It is unfolding in appellate briefs, Supreme Court petitions and state enforcement rules, with Illinois serving as a major test case while judges decide how much weight to give laws written in the founding era and how closely those laws map onto modern AR-15-style rifles.