The dispute centers on drawing a line between weapons deemed unusual and arms that are regularly used for legitimate ends.
The Trump administration has repeatedly challenged bans labeled as “assault weapons,” arguing that such prohibitions infringe the Second Amendment by restricting arms that are in broad lawful use. In a Supreme Court brief filed last Friday, Solicitor General D. John Sauer expands that argument, detailing the reasoning behind separating arms that are commonly used from those deemed “dangerous and unusual.”
That distinction sits at the core of two consolidated cases the Court will hear on December 2: Viramontes v. Cook County, addressing that Illinois jurisdiction’s similar ban on assault weapons, and Grant v. Higgins, which concerns a Connecticut statute with a comparable aim. The central issue is whether the Second Amendment protects “the right to possess AR-15 platform and similar semiautomatic rifles,” as these laws address. Sauer maintains that the answer is yes, reiterating the Justice Department’s Civil Rights Division position in multiple lawsuits.
“A firearms restriction conforms with the Second Amendment only if it is ‘consistent with the Nation’s historical tradition of firearm regulation,'” Sauer writes, invoking the standard laid out by the Supreme Court in New York State Rifle & Pistol Association v. Bruen. “And this nation’s regulatory tradition precludes prohibiting arms that are ‘in common use’ by law-abiding citizens for lawful purposes. The common-use test has deep roots in English and American legal history. The Court has already adopted that test and has repeatedly applied it to assess the validity of arms bans.”
From Sauer’s perspective, that framework suffices to resolve the issues raised by these cases, since “the AR-15 rifle is indisputably in common use among law-abiding citizens for lawful purposes.” He notes that such rifles “are lawful at the federal level and in 40 states.” “The vast majority of AR-15 owners possess these rifles for lawful uses to which they are suited, such as self-defense within the home, hunting, and target shooting. A prohibition on possessing such rifles thus infringes the Second Amendment.”
The U.S. Court of Appeals for the 7th Circuit, which sustained Cook County’s AR-15 ban in June 2025, took a different view, following its 2023 decision in Bevis v. City of Naperville, which held that such rifles can be prohibited because they resemble “military-grade weapons.” A couple of months later, the U.S. Court of Appeals for the 2nd Circuit likewise ruled that Connecticut’s rifle restrictions were consistent with the Second Amendment, arguing they targeted “unusually dangerous weapons while preserving numerous legal alternatives for self-defense and other lawful purposes.”
Neither court afforded dispositive weight to the notion that broad AR-15 ownership is constitutionally conclusive. Yet Sauer emphasizes that the premise rests on a solid historical footing: “Three bodies of historical evidence—militia laws, laws governing going armed, and state-court rulings—show that the common-use test has deep roots in English law, was settled in the United States by the founding, and was widely applied in the 19th century.”
Under “militia laws stretching back nearly a millennium,” the brief notes, “individuals had not just the right but the duty to maintain arms in common use.” That tradition carried over from England to America. At the Founding, the Supreme Court observed in the landmark 2008 case District of Columbia v. Heller that the “well regulated militia” to which the Second Amendment refers “was formed from a pool of men bringing arms
‘in common use at the time’ for lawful purposes like self-defense.” State and federal militia laws thus required those men to “supply themselves with arms ‘of the kind in common use.'”
That historical backdrop “explains the link between the Second Amendment’s prefatory clause (‘A well regulated Militia, being necessary to the security of a free State’) and its operative clause (‘the right of the people to keep and bear Arms, shall not be infringed’),” Sauer says. “The founders feared that the new federal government would ‘destroy the citizens’ militia by taking away their arms.’ Consequently, they codified an individual right to retain and carry the sort of arms used by the militia—arms ‘typically possessed by law-abiding citizens for lawful purposes.'”
That point underscores what Sauer sees as the illogic of the 7th Circuit’s reasoning, which posits that arms particularly valuable in military contexts fall outside the scope of the Second Amendment. “The founders would have been astonished to hear that legislatures may ban arms in common use if those arms can also be used for military purposes,” Sauer writes.
Lawful-goings-armed laws, dating back to the 1328 Northampton Statute, reinforce the distinction between “arms in common use” and other weapons. “A person could violate the statute by publicly carrying ‘dangerous and unusual weapons’ in a manner that terrified the community,” Sauer observes. That category included “lances that were typically carried only by those seeking combat or to breach the peace” but “not daggers,” which “were often carried by law-abiding subjects for self-defense.” An eighteenth-century treatise noted that a person was “‘in no Danger of Offending against this Statute by wearing common Weapons.'”
On the other side of the Atlantic, nineteenth-century state statutes drew a parallel line, aiming at “dangerous and unusual weapons” tied to “duels, brawls, and other criminal acts,” such as Bowie knives, spears, sword canes, slungshots, and brass knuckles. In reviewing these laws, state courts applied the common-use standard.
In 1871, for instance, the Tennessee Supreme Court held that legislators could ban weapons that were “not usual” but could not prohibit “the usual arms of the citizen.” The highest courts in Texas, Arkansas, West Virginia, North Carolina, and Michigan concurred that the right to bear arms encompassed weapons commonly owned by law-abiding people, including rifles.
In United States v. Miller (1939), the Supreme Court sustained the federal ban on short-barreled shotguns, noting that the petitioner, an armed bootlegger, had failed to demonstrate that “possession or use of a ‘shotgun having a barrel of less than eighteen inches in length’ at this time has some reasonable relationship to the preservation or efficiency of a well regulated militia.” The Court doubted that “this weapon is any part of the ordinary military equipment or that its use could contribute to the common defense.”
When the Second Amendment was adopted, the militia consisted of all males physically capable of acting together for the common defense, the justices observed. “Ordinarily when called for service these men were expected to appear bearing arms supplied by themselves and of the kind in common use at the time.”
Like the state court decisions cited by Sauer, Miller dealt with a weapon barred due to its association with criminal activity. But contrary to the 7th Circuit’s stance on the scope of the Second Amendment, the decision implied that the right to possess a short-barreled shotgun would be constitutionally protected if it could be shown that such firearms were “in common use” and militarily appropriate.
The Supreme Court reaffirmed the common-use standard in Heller, rejecting the District of Columbia’s ban on handguns, which the majority described as “the quintessential self-defense weapon” and “the most popular weapon chosen by Americans for self-defense in the home.” The Court was unpersuaded by the fact that criminals also favored handguns, stating that a categorical ban on arms in common use for lawful purposes was plainly inconsistent with the Second Amendment.
In Bruen, the Court reiterated that “the Second Amendment protects the possession and use of weapons that are ‘in common use at the time,'” including handguns, which are “indisputably in ‘common use’ for self-defense today.” It contrasted that category with arms that are “highly unusual in society at large.”
Sauer contends that “traditional legislative practice provides a useful guide to applying the common-use test.” Although semi-automatic rifles have been commercially available in the United States for roughly 120 years, he notes, they “have not historically been banned” or “even subjected to heavy regulation.” The fact that four-fifths of the states view AR-15s as legitimate arms, he adds, “indicates that they are in common use.”
So do sales and survey data. According to the latest figures from the National Shooting Sports Foundation, the gun industry’s trade association, Americans own more than 32 million “modern sporting rifles,” the group’s term for the models targeted by “assault weapon” bans. Surveys suggest that between 16 million and 25 million Americans have owned AR-15-style rifles, which they commonly report using for lawful purposes such as self-defense, hunting, and target shooting. Last year, a unanimous Supreme Court described the AR-15 as “the most popular rifle in the country.”
Nevertheless, appellate courts have questioned the usefulness of AR-15s for self-defense, argued they are better suited to the battlefield, and claimed they are especially deadly when used in mass shootings. Although Sauer counters each point, his verdict remains that these considerations are irrelevant under the Second Amendment, which prevents lawmakers from substituting their judgments for those of millions of law-abiding gun owners. It makes no exception for weapons with military lineage (which, as Sauer notes, includes widely used handguns like the Glock 17), firearms that could be employed to commit mass murder (predominantly handguns), or weapons favored by ordinary criminals (also overwhelmingly handguns).
Heller decisively rejected the notion that a weapon’s prominence in homicide statistics justifies prohibiting law-abiding people from possessing it. “Rifles are in many ways less dangerous than handguns, which Heller holds cannot be banned,” Sauer notes. “Handguns, which are easier to carry and conceal than rifles, ‘are the overwhelmingly favorite weapon of armed criminals.’ The FBI estimates that, of the 13,674 homicides in 2025, 5,179 (about 38%) were committed with handguns, while 363 (about 3%) involved rifles of any kind—even though millions of Americans own rifles. Handguns are also used in mass shootings, and some studies have found that ‘a victim’s probability of death is higher in shootings involving a handgun than in shootings involving a rifle.’
Given all this, “holding that the Second Amendment protects handguns but not rifles would be ‘backwards,'” Sauer asserts, quoting Justice Brett Kavanaugh’s 2011 dissent from a D.C. Circuit ruling upholding the District of Columbia’s “assault weapon” ban. Along with Kavanaugh, Justices Clarence Thomas, Samuel Alito, and Neil Gorsuch have signaled a propensity to view such laws as failing the Bruen test. And Bruen itself, which Chief Justice John Roberts and Justice Amy Coney Barrett joined, reaffirmed the common-use standard, suggesting that Cook County and Connecticut face an uphill battle.
