Cook County, Connecticut Defend AR-15 Bans in Supreme Court Briefs Ahead of December Arguments
Cook County and Connecticut challenge the common-use protection recognized in Heller, arguing that even firearms owned by millions of law-abiding Americans can be banned if governments consider them unusually dangerous.
Cook County, Illinois, and Connecticut are asking the U.S. Supreme Court to uphold their AR-15 bans by rejecting a central argument drawn from District of Columbia v. Heller: that firearms commonly possessed by law-abiding Americans for lawful purposes cannot be categorically prohibited. Their newly submitted briefs challenge the constitutional significance of common use, arguing that governments retain authority to outlaw widely owned rifles if lawmakers and courts consider them unusually dangerous.
The arguments strike at the heart of the Supreme Court’s modern Second Amendment jurisprudence. In Heller, the Court recognized an individual right to keep and bear arms and explained that the Second Amendment protects weapons in common use for lawful purposes. Now Cook County and Connecticut want the justices to conclude that widespread lawful ownership does not prevent governments from banning America’s most popular semiautomatic rifle.
The October 21 briefs were submitted in Viramontes v. Cook County, No. 25-238, and Grant v. Higgins, No. 25-566. The consolidated cases challenge state and local prohibitions on AR-15s and similar semiautomatic rifles. Oral arguments are scheduled for December 2.
Neither government expressly asks the Supreme Court to overturn Heller. Instead, both advance interpretations that would substantially weaken its common-use protection, allowing legislatures to prohibit widely owned firearms based on claims about lethality, military characteristics, and public safety.
That distinction matters because the consequences could extend well beyond AR-15s. If common lawful ownership cannot protect an ordinary rifle from prohibition, the same reasoning could eventually be directed against other semiautomatic rifles, handguns, and firearms politicians consider too effective for civilian possession.
Cook County and Connecticut have just filed their briefs in Viramontes and Higgins.
This thread will look at the Cook County brief first. To the extent the Connecticut brief differs in substance, we’ll cover that here too.
— SAF (@2AFDN) October 21, 2026
Cook County Argues Common Use Does Not Determine Constitutional Protection
In its 78-page Supreme Court brief, Cook County devotes an entire section to challenging the petitioners’ reliance on Heller.
The county’s position is unmistakable. One subsection is titled “Common Use Is Not Determinative of Constitutional Protection.” Cook County argues that the widespread ownership of AR-15s cannot prevent it from restricting the firearms if its ordinance otherwise satisfies the historical-tradition analysis required by New York State Rifle & Pistol Association v. Bruen.
The county contends that Heller’s common-use language helps determine whether a weapon falls within the Second Amendment’s text but does not automatically resolve whether the government can prohibit it. It cites Bruen’s examination of historical regulations involving handguns to argue that widely owned firearms remain subject to additional constitutional scrutiny.
That approach would allow Cook County to acknowledge the widespread ownership of AR-15s while still insisting that they fall within a category of weapons government officials may prohibit.
But the Second Amendment does not grant governments unlimited discretion to designate commonly possessed firearms as unusually dangerous. Heller recognized common lawful ownership as an important constitutional protection, not simply an inconvenient fact that lawmakers could acknowledge before proceeding with a ban.
Cook County goes further by arguing that Americans’ lawful ownership of AR-15s does not answer the government’s public-safety concerns.
The brief states:
“It is no answer that the vast majority of those who own AR-15 platform weapons pose no risk and seek to cause no harm.”
That admission exposes the danger of the county’s constitutional theory. Cook County acknowledges that the overwhelming majority of AR-15 owners are peaceful Americans, yet argues that government officials can still prohibit their firearms because of what criminals might do with similar weapons.
The Second Amendment protects the rights of individuals, not merely the interests of those whom governments consider sufficiently safe to exercise them.
Connecticut Challenges Heller’s Common-Use Rule
Connecticut’s 85-page merits brief advances a similar position, but its attack on common use is even more direct.
The state devotes an entire major section to arguing that the petitioners’ common-use-only test lacks merit. Attorney General William Tong’s office, represented in part by former U.S. Solicitor General Elizabeth Prelogar, maintains that historically governments restricted certain weapons even after those weapons became widely possessed.
Connecticut relies on the Fourth Circuit’s decision in Bianchi v. Brown, which upheld Maryland’s restrictions on certain semiautomatic rifles, to argue:
“Just because a weapon happens to be in common use does not guarantee that it falls within the scope of the right to keep and bear arms.”
The state contends that widespread civilian ownership cannot prevent a government from prohibiting weapons it considers unusually dangerous compared with other firearms.
This interpretation would give lawmakers considerable authority to decide which firearms remain available to ordinary Americans, even after millions have selected those arms for lawful purposes.
Connecticut also attempts to turn the expiration of the 1994 federal assault weapons ban into an argument against constitutional protection.
The state reasons that if common use prevents categorical bans, Congress may have retained authority to prohibit AR-15s before widespread civilian adoption but lost that authority after the federal ban expired in 2004 and millions of Americans lawfully acquired the rifles.
Connecticut objects to that result, declaring:
“The Second Amendment does not create that one-way ratchet.”
But the question before the Supreme Court is not whether Congress should have prevented Americans from purchasing AR-15s before they became popular. It is whether a government can prohibit firearms currently possessed by millions of law-abiding citizens for lawful purposes.
The hypothetical constitutional status of a newly introduced firearm cannot erase the existing protection of an arm already widely owned throughout the country.
Connecticut’s argument also raises a larger problem. If the government can prohibit firearms regardless of their common lawful use, what meaningful protection does the common-use principle actually provide?
Millions of Americans Own AR-15s for Lawful Purposes
The ownership evidence makes these cases particularly important. As AmmoLand previously reported in its comprehensive review of the Supreme Court amicus briefs, Professor William English’s 2026 National Firearms Survey estimates that approximately 26.4 million American adults own an AR-15-type or similarly styled semiautomatic rifle, with approximately 60 million such rifles in civilian possession.
These are survey estimates covering AR-15-type and similarly styled rifles, rather than an exact count of AR-15s alone. Nevertheless, they demonstrate that the firearms targeted by the challenged prohibitions are firmly established in ordinary American gun ownership.
Americans possess these rifles for home defense, recreational shooting, competition, hunting, training, and other lawful activities. Their widespread adoption is not evidence of some unusual class of weapon operating outside normal civilian use.
The right to possess a firearm for self-defense also cannot be measured by the number of times its owner actually fires it at an attacker.
Cook County argues that AR-15s are not customarily used in defensive shootings and questions whether ownership surveys establish their defensive role. But an American who keeps a rifle for home protection does not lose that purpose merely because he never experiences a home invasion.
The Second Amendment protects the right to keep arms before an emergency occurs. Requiring gun owners to demonstrate actual defensive use before recognizing constitutional protection would turn the right on its head.
Second Amendment Foundation Executive Director Adam Kraut rejected the governments’ effort to justify categorical prohibitions.
“Categorical bans on the most commonly owned rifles in America violate the Second Amendment, full stop,” said Kraut.
He also criticized laws that target ordinary semiautomatic rifles based on features such as adjustable stocks and grip configurations, arguing that the Supreme Court’s existing constitutional standards do not permit the challenged prohibitions.
Historical Bowie Knife and Trap Gun Laws Cannot Justify AR-15 Possession Bans
To overcome the constitutional significance of common use, both governments rely heavily on historical restrictions involving other weapons.
Cook County cites laws addressing Bowie knives, trap guns, armed assemblies, and public affray. Connecticut turns to medieval English weapons restrictions, including lancegays, before discussing American laws governing Bowie knives, pistols, and other arms.
But many of those restrictions addressed conduct fundamentally different from peaceful ownership of a rifle.
Trap-gun laws targeted firearms configured to discharge through dangerous traps. Affray laws addressed threatening public conduct, while restrictions on armed assemblies concerned unlawful collective activity. Historical Bowie knife regulations frequently addressed concealed carry, public carry, sales, or taxation rather than broad prohibitions on possession.
These distinctions are central to the historical analysis required by Bruen and United States v. Rahimi. Historical regulations need not be identical to modern laws, but the burdens they impose and the problems they address must be sufficiently analogous.
A law against setting a firearm as a trap does not establish a historical tradition of prohibiting peaceful Americans from keeping an ordinary rifle.
The governments’ briefs also struggle with a more relevant historical comparison: revolvers and repeating rifles.
Henry and Winchester repeating rifles represented substantial advancements in practical firepower during the nineteenth century. Revolvers similarly expanded the capabilities of privately owned firearms. Yet the governments have not established a comparable national tradition of prohibiting peaceful ownership of these weapons simply because they were technologically superior to their predecessors.
The Second Amendment did not freeze firearms technology at the flintlock era.
The originalist argument is straightforward: Constitutional protection follows the right and the historical understanding of protected arms, not government approval of a particular generation of technology.
Cook County Treats Military Usefulness as a Reason to Ban Rifles
Cook County’s arguments also challenge the historical militia purpose of the Second Amendment.
The county emphasizes the AR-15’s military origins and similarities to military rifles, presenting battlefield suitability as evidence that the firearm is disproportionately dangerous for ordinary civilians.
But the Founders understood the militia as an armed citizenry, and privately owned arms suitable for the common defense were central to that arrangement.
Cook County addresses the United States’ argument that rifles appropriate for repelling invasions, suppressing insurrections, and resisting tyranny serve constitutionally protected purposes.
The county responds:
“Today, of course, these responsibilities are reserved for the United States military.”
It acknowledges the Founders’ distrust of standing armies but argues that the modern professional military has assumed responsibilities historically associated with armed citizens.
The existence of a professional military, however, did not repeal the Second Amendment. The government’s development of an organized standing army cannot eliminate the people’s separate constitutional right to keep and bear arms.
As AmmoLand previously reported in its examination of militia-suitable firearms, military usefulness has historically supported constitutional protection rather than disqualified an arm from civilian ownership.
Nor does an ordinary semiautomatic AR-15 become a machine gun because its design shares features with military rifles. Civilian AR-15s fire one round per trigger pull, and ergonomic similarities do not change their operating mechanism.
The county’s argument effectively asks the Supreme Court to turn an important purpose of the Second Amendment into a reason to narrow its protection.
Anti-gun Governments Argue AR-15s Are Too Dangerous Because They Are Effective Firearms
Both governments attempt to justify their prohibitions by emphasizing the AR-15’s ballistic capabilities.
Cook County discusses projectile velocity, kinetic energy, penetration, effective range, and the serious injuries that rifle ammunition can produce. Connecticut similarly describes the rifles as unusually dangerous because of their ability to deliver accurate semiautomatic fire.
But many of the capabilities being criticized are common characteristics of centerfire rifles generally.
Numerous traditional hunting rifles fire cartridges with greater muzzle energy than .223 Remington or 5.56 NATO. Effective range and penetration are not exclusive to the AR-15 platform, nor are accuracy and controllability constitutional defects.
If those characteristics justify banning semiautomatic AR-15s, the same reasoning could eventually be directed against ordinary bolt-action hunting rifles and other conventional firearms.
Cook County also invokes the possibility of illegally converting semiautomatic rifles into automatic weapons. But criminal modification does not change the legal or mechanical characteristics of the original, unmodified firearm.
The potential for someone to commit an illegal act with a firearm does not eliminate another person’s constitutional right to possess it.
Ultimately, these arguments ask the Supreme Court to place the government’s judgment about firearm effectiveness above the constitutional protection afforded to the people who own them.
Cook County Says Gun Owners Can Move Somewhere Else
Cook County’s approach to common use also leads it to an extraordinary argument about the geographic limits of constitutional rights.
The county contends that different states and local governments should be permitted to adopt different firearms restrictions based on their citizens’ preferences.
Quoting a federal appellate decision, the county suggests that Americans dissatisfied with local prohibitions can:
“vote with their feet and move to a jurisdiction where their views have prevailed.”
That reasoning treats an enumerated constitutional right as though it were merely a local policy preference.
The Bill of Rights does not protect liberties only in jurisdictions where elected officials approve of their exercise. Its purpose is to restrain government power, including when political majorities support restricting individual rights.
An American should not have to leave Illinois or Connecticut to exercise a right protected by the United States Constitution.
The Second Amendment applies throughout the country, and the constitutional protection of ordinary arms cannot depend on the ideological preferences of a county board or state legislature.
Supreme Court Faces a Defining Test of Heller’s Common-Use Protection
The constitutional stakes extend well beyond Cook County and Connecticut.
The United States has filed in support of the petitioners challenging the bans, and Solicitor General D. John Sauer has requested time to present the federal government’s position during oral arguments.
A coalition of 27 states has also urged the Supreme Court to reject AR-15 prohibitions, emphasizing the constitutional protection owed to firearms commonly possessed for lawful purposes.
SAF is joined in Viramontes by the Firearms Policy Coalition and two private citizens. In Grant, its fellow plaintiffs include the Connecticut Citizens Defense League and three private citizens.
The Court’s eventual ruling could also affect other challenges to rifle and magazine prohibitions, including litigation involving New Jersey’s restrictions.
SAF founder and Executive Vice President Alan M. Gottlieb criticized the continued defense of categorical bans on widely owned rifles.
“It’s high time that assault weapons bans recede back into the primordial ooze of gun control legislation from which they emerged,” said Gottlieb.
The argument before the Supreme Court is ultimately about whether Heller’s recognition of protection for commonly possessed arms places meaningful limits on government authority.
Cook County and Connecticut want the justices to accept that widespread lawful ownership does not prevent the government from prohibiting firearms it considers unusually dangerous. Their supporting arguments about historical weapons restrictions, military utility, public safety, and ballistic effectiveness all serve that larger objective.
If the Court accepts such a broad theory, the constitutional consequences may reach far beyond the AR-15.
The Second Amendment does not give lawmakers permission to ban ordinary arms merely because government officials believe those firearms are too effective or unnecessarily dangerous. Nor should millions of peaceful Americans lose constitutional protection because criminals have misused similar weapons.
When the justices hear arguments on December 2, they will confront a fundamental question: Does the Constitution protect the firearms Americans commonly possess for lawful purposes, or can the government override that protection by declaring those arms unsuitable for civilian ownership?
Heller recognized that the Second Amendment protects arms in common use for lawful purposes. Viramontes and Grant now give the Court an opportunity to make clear whether governments can continue evading that protection by labeling America’s most popular rifle unusually dangerous.
About Duncan Johnson:
Duncan Johnson is a lifelong firearms enthusiast and unwavering defender of the Second Amendment—where “shall not be infringed” means exactly what it says. A graduate of George Mason University, he enjoys competing in local USPSA and multi-gun competitions whenever he’s not covering the latest in gun rights and firearm policy. Duncan is a regular contributor and editor-in-chief for AmmoLand News and is responsible for AmmoLand’s daily gun-rights reporting and industry coverage.