“America’s Rifle” Goes to the Supreme Court: Viramontes v. Cook County Could Spell the End of Massachusetts’ “Assault-Style Firearm” Ban

For decades, states such as Massachusetts, Connecticut, Illinois, California, New York and New Jersey have prohibited ordinary citizens from acquiring some of the most popular semiautomatic rifles in America. The justification is familiar: legislators label these firearms “assault weapons” or, as Massachusetts now calls them, “assault-style firearms,” characterize them as unusually dangerous, and argue that citizens remain free to defend themselves with some other firearm.

A major new case before the United States Supreme Court may finally determine whether that approach can survive the Second Amendment.

On August 28, 2026, the petitioners filed their merits brief in Viramontes v. Cook County, No. 25-238, consolidated with Grant v. Higgins, No. 25-566. The Supreme Court granted certiorari on June 30, 2026, on an extraordinarily important and straightforward question:

“Whether the Second and Fourteenth Amendments guarantee the right to possess AR-15 platform and similar semiautomatic rifles.”

The petitioners’ answer is equally straightforward: yes.

And if the Supreme Court agrees, the consequences for Massachusetts could be enormous.

Massachusetts currently prohibits possession, acquisition and transfer of broadly defined “assault-style firearms” under G.L. c. 140, § 131M, subject to grandfathering and specified exceptions. The Legislature substantially revised and expanded the Commonwealth’s firearms laws through Chapter 135 of the Acts of 2024. Viramontes now gives the Supreme Court an opportunity to decide whether governments may constitutionally prohibit law-abiding citizens from possessing rifles that are owned by millions of Americans throughout the country.

The Core Argument: AR-15s Are “Arms”

The petitioners begin with the constitutional text. The Second Amendment protects “the right of the people to keep and bear Arms.” Under District of Columbia v. Heller, 554 U.S. 570 (2008), the historical meaning of “arms” encompasses weapons of offense or defense. The petitioners therefore argue that an AR-15 is unquestionably an “Arm.” That proposition should seem almost self-evident, yet it matters enormously because lower courts have sometimes attempted to load additional considerations into the threshold question of whether a particular weapon receives Second Amendment protection at all. The petitioners argue that this gets the analysis backwards. Whether judges believe an AR-15 is too dangerous, too military-looking, unnecessary for self-defense, or sufficiently different from another rifle has nothing to do with whether it is an “Arm.” It plainly is. Once the regulated conduct falls within the Second Amendment’s text, New York State Rifle & Pistol Association v. Bruen, 597 U.S. 1 (2022), requires the government to justify its restriction through the Nation’s historical tradition of firearm regulation. The petitioners argue that Cook County and Connecticut cannot do so.

Heller Already Gave Us the Rule: Common Arms Cannot Be Banned

This is perhaps the most important argument in the entire brief. The petitioners maintain that the Court does not need to reinvent Second Amendment law to decide Viramontes because Heller already supplied the answer. The constitutional line is between weapons that are commonly possessed by ordinary citizens for lawful purposes and weapons that are properly characterized as “dangerous and unusual.” Those concepts are critically connected: a firearm possessed by tens of millions of ordinary Americans cannot plausibly be called “unusual.” The petitioners accordingly argue that AR-15s fall comfortably within Heller’s protection. Millions of Americans own them, a substantial majority of states permit them, and they are overwhelmingly possessed for lawful purposes.

The brief relies heavily upon the Supreme Court’s own recent description of the AR-15. In Smith & Wesson Brands, Inc. v. Estados Unidos Mexicanos, 605 U.S. 280 (2025), a unanimous Supreme Court described the AR-15 as “the most popular rifle in the country.”

That observation creates an obvious problem for an “assault weapons” ban. How can the most popular rifle in America simultaneously be an “unusual” weapon outside the protection of the Second Amendment? The petitioners’ answer is that it cannot. Their brief cites recent survey evidence suggesting that approximately 26 million individual Americans own at least one rifle within the relevant category and approximately 22 million Americans own an AR-15-platform rifle. The constitutional question, in their view, therefore should not be close.

The Government Cannot Decide That Americans Chose the “Wrong” Gun

There is a deeper principle underlying the common-use argument: who decides what firearm Americans need—the government, judges, or the people exercising the constitutional right? Heller already confronted essentially the same argument concerning handguns. Washington, D.C. contended that citizens still had access to long guns notwithstanding its handgun prohibition, and the Supreme Court rejected that argument. As Heller famously explained, constitutional rights remove certain policy choices from the political branches. The Viramontes petitioners contend that precisely the same principle applies to AR-15s. Government cannot answer a challenge to an AR-15 ban by saying that citizens remain free to buy a shotgun, revolver, bolt-action rifle, or some other government-approved firearm. The Second Amendment does not merely require government to leave citizens some firearm; it protects the people’s right to keep and bear arms. If Americans have overwhelmingly selected a particular firearm for lawful purposes, the petitioners argue, courts cannot substitute their judgment for the people’s choice.

“Dangerous AND Unusual” — Not Merely “Dangerous”

Another crucial feature of the brief concerns a phrase that has become enormously important after Heller: “dangerous and unusual.”

The petitioners emphasize that the historical test is conjunctive. A weapon does not lose constitutional protection merely because the government calls it dangerous. That would make little sense. Firearms are weapons, and virtually every firearm is capable of causing serious injury or death. A rule permitting prohibition whenever government demonstrates that a firearm is “dangerous” would threaten the very arms Heller expressly held constitutionally protected. Instead, the historical tradition concerns dangerous and unusual weapons.

That distinction was prominently discussed in Caetano v. Massachusetts, 577 U.S. 411 (2016), where the Supreme Court unanimously vacated a Massachusetts decision upholding a stun-gun prohibition. Justice Alito’s concurrence emphasized that an arm may not be prohibited unless it is both dangerous and unusual.

That case has particular significance for Massachusetts. The Supreme Court has already once corrected Massachusetts for construing the Second Amendment too narrowly when determining which weapons receive constitutional protection.

Viramontes could provide another, considerably broader correction.

Courts Cannot Resurrect Interest Balancing After Bruen

The petitioners also attack what has become a recurring feature of lower-court Second Amendment decisions: courts formally claiming to apply Bruen while effectively returning to the interest-balancing methodology that Bruen rejected. Arguments about mass shootings, criminal misuse, relative lethality, the availability of alternative firearms, or whether judges consider a particular weapon “necessary” for self-defense may sound like public-policy arguments, but that is precisely the problem. Bruen rejected means-end scrutiny. The petitioners argue that courts cannot resurrect it by simply calling the same policy analysis “history.”

Once an arm is commonly possessed by law-abiding Americans for lawful purposes, the government cannot prohibit it because legislators or judges conclude that its dangers outweigh its benefits.

As Heller put it, the enumeration of a constitutional right removes from government the power to decide on a case-by-case basis whether that right is worth insisting upon.

That principle may prove devastating to laws premised primarily upon legislative declarations about the perceived dangerousness of semiautomatic rifles- the same ones that have existed, by the way, for decades.

An AR-15 Is Not a Machine Gun

The petitioners also confront one of the most persistent rhetorical devices used to defend these laws: attempting to associate AR-15s with machine guns or military automatic weapons. Mechanically, they are different. An ordinary AR-15 is semiautomatic: one trigger pull fires one round. It does not become a machine gun because it has a pistol grip, adjustable stock, barrel shroud, flash suppressor, or other feature that legislators have chosen to place on a prohibited-features list. Indeed, the petitioners argue that many of the supposedly dangerous characteristics targeted by these laws do not increase a rifle’s rate of fire or power at all. Adjustable stocks accommodate shooters of different sizes, pistol grips assist the shooter in holding and controlling a straight-stocked rifle, and other features can reduce muzzle movement, assist aiming, or reduce muzzle flash.

The brief’s point is powerful: many of the features condemned by “assault weapons” legislation actually make a firearm easier to control and more accurate.

It is difficult to explain why constitutional protection should decrease as a firearm becomes easier for its lawful owner to control.

The Historical Analogues Don’t Work

The petitioners then turn to history. Historical laws regulating the threatening public carry of weapons do not establish a tradition of prohibiting peaceful possession of commonly owned firearms inside the home. Nor, they argue, do nineteenth-century restrictions involving Bowie knives save modern rifle bans. Many of those laws concerned concealed carry or misuse rather than possession; others were enacted decades after ratification; still others were historical outliers.

And twentieth-century firearm restrictions are even less useful. The petitioners argue that semiautomatic restrictions were rare, often concerned magazine capacity rather than the firearms themselves, and arrived far too late in American history to establish the original scope of the Second Amendment.

There simply was no American historical tradition of allowing government to prohibit ordinary citizens from possessing an entire category of commonly owned arms because legislators considered those arms excessively dangerous.

What Does All of This Mean for Massachusetts?

For Massachusetts gun owners, this may be the most important part of the case. The petitioners’ Supreme Court brief actually cites Massachusetts General Laws chapter 140, § 131M(a) among the modern state laws prohibiting these firearms. Massachusetts is therefore not merely analogous to the laws before the Court; its prohibition is expressly identified in the petitioners’ discussion of the nationwide regulatory landscape.

Under the current Massachusetts statute, G.L. c. 140, § 131M(a) provides that, subject to exceptions, “[n]o person shall possess, own, offer for sale, sell or otherwise transfer in the commonwealth or import into the commonwealth an assault-style firearm, or a large capacity feeding device.”

The 2024 legislation includes grandfathering for certain assault-style firearms lawfully possessed in Massachusetts on August 1, 2024, but otherwise imposes a categorical prohibition.

That matters because Viramontes is not merely about some technical licensing condition. It concerns the fundamental question whether government can prohibit a class of semiautomatic rifles in the first place.

Massachusetts Has the Same “Common Use” Problem

The Commonwealth faces the same fundamental problem as Cook County and Connecticut: Massachusetts cannot make AR-15s “unusual” simply by banning them within Massachusetts. Common use is a national constitutional inquiry. A state cannot manufacture the rarity necessary to justify a prohibition by first prohibiting the firearm and then pointing to its resulting rarity inside the jurisdiction. If approximately 22 million Americans own AR-15-platform rifles, the Commonwealth should not be able to evade Heller simply because Massachusetts legislators prefer that Massachusetts residents not be among them. Constitutional rights are national rights, and the Second Amendment does not become weaker when one crosses the Massachusetts border.

Massachusetts’ Feature-Based Definitions Face the Same Problem

The Massachusetts law also relies upon definitions and characteristics to distinguish prohibited “assault-style firearms” from other semiautomatic firearms. But Viramontes attacks the constitutional relevance of precisely these sorts of distinctions. A pistol grip does not convert a semiautomatic rifle into a machine gun; neither does an adjustable stock, a barrel shroud, or a muzzle device. If the Supreme Court accepts the petitioners’ reasoning that such features do not remove an otherwise common semiautomatic rifle from Second Amendment protection, Massachusetts’ attempts to classify firearms according to comparable characteristics become constitutionally vulnerable.

Massachusetts Cannot Answer: “You Can Buy Another Gun”

Another likely argument supporting Massachusetts’ law is that residents remain permitted to possess many other firearms. But Heller rejected that reasoning. The availability of government-approved alternatives does not cure a ban on a constitutionally protected arm. Imagine applying that theory to another constitutional right: government could hardly prohibit newspapers while arguing that citizens remain free to read books, or prohibit one religion while observing that hundreds of others remain available. The existence of alternative means of exercising a constitutional right does not necessarily authorize government to prohibit the protected means citizens actually choose. If AR-15s are protected arms in common use, Massachusetts cannot save its prohibition by pointing toward firearms it would rather citizens purchase.

The Massachusetts Ban May Have an Especially Serious Historical Problem

Massachusetts also must contend with Bruen’s historical requirement. Where is the Founding-era tradition of categorically prohibiting ordinary citizens from possessing commonly owned rifles in their homes? That is the question. Historical restrictions against carrying weapons in a threatening manner are not equivalent; restrictions upon concealed Bowie knives are not equivalent; and laws punishing misuse of weapons are not equivalent. Nor can twentieth-century firearm legislation enacted generations after the Second and Fourteenth Amendments, by itself, establish the historical understanding of the right.

If the Supreme Court holds that no relevant historical tradition supports the Cook County and Connecticut prohibitions, Massachusetts will face the same historical deficiency.

And Massachusetts Has Another Problem: Caetano

There is a remarkable historical irony here. One of the Supreme Court decisions upon which the Viramontes petitioners rely most heavily arose from Massachusetts itself. In Caetano v. Massachusetts, the Supreme Judicial Court had concluded that stun guns fell outside Second Amendment protection in part because they did not exist at the Founding. The United States Supreme Court unanimously rejected that reasoning, reminding Massachusetts that the Second Amendment extends to arms that did not exist in the eighteenth century. That principle applies with equal force to semiautomatic rifles.

Massachusetts cannot avoid the Second Amendment merely because modern firearms incorporate technology unknown in 1791. The First Amendment protects the Internet despite the absence of websites at the Founding. The Fourth Amendment applies to smartphones despite the absence of digital data in the eighteenth century.

Constitutional principles govern modern technology.

Caetano already established that proposition specifically against Massachusetts in the Second Amendment context.

This Case Could Finally Resolve the “Assault Weapons” Question

There is an important reason gun-rights advocates should watch Viramontes especially closely. The Supreme Court is no longer merely being asked whether it should hear an AR-15 case: it has agreed to hear one. The Court granted certiorari on the explicit question whether the Second and Fourteenth Amendments protect the right to possess “AR-15 platform and similar semiautomatic rifles.” That framing puts the central constitutional question squarely before the Justices.

A holding that AR-15s and similar semiautomatic rifles are “Arms,” are commonly possessed by law-abiding Americans for lawful purposes, and therefore cannot constitutionally be prohibited would place statutes such as Massachusetts G.L. c. 140, § 131M in immediate constitutional jeopardy.

And the ramifications could extend beyond rifles.

The logic of the petitioners’ common-use argument potentially bears upon restrictions on commonly possessed magazines as well. That issue is not identical to the question formally presented in Viramontes, and the Court need not decide magazine restrictions to resolve this case. But a strong Supreme Court reaffirmation that government cannot prohibit commonly possessed arms merely because it considers them unusually dangerous would inevitably influence litigation over magazine-capacity restrictions.

The Fundamental Question: Who Chooses the Arms?

Ultimately, Viramontes presents a question considerably larger than the AR-15. It asks who decides what arms ordinary Americans may possess. The government believes it may draw that line according to its assessment of which firearms are too dangerous; the petitioners respond that the Constitution already drew the line.

Under their reading of Heller, McDonald, Caetano and Bruen, arms commonly possessed by law-abiding citizens for lawful purposes are protected. Government retains broad authority to punish criminal misuse of firearms and historically grounded authority to regulate conduct involving weapons. But it cannot transform a commonly owned firearm into contraband simply because legislators disapprove of the people’s choice.

That is particularly important in Massachusetts. The Commonwealth has progressively expanded its firearms restrictions while repeatedly assuring citizens that each new restriction represents merely another “reasonable” public-safety measure. But Bruen rejected “reasonable regulation” as the constitutional test. The question is not whether Massachusetts legislators believe their prohibition is sensible, whether judges believe AR-15s are necessary, or whether the Commonwealth can produce studies suggesting that prohibiting them might advance public safety. The constitutional question is whether the Second Amendment protects them.

And if the Supreme Court accepts the argument now placed before it in Viramontes, the answer will be unmistakable:

The AR-15 is an “Arm.” It is owned by millions of ordinary Americans. It is commonly possessed for lawful purposes. And government cannot ban it merely because government would prefer that Americans choose something else.

For Massachusetts gun owners, Viramontes v. Cook County therefore may become one of the most consequential Second Amendment cases since Bruen.

The Supreme Court now has an opportunity to make explicit what Heller arguably established eighteen years ago:

A firearm cannot simultaneously be one of America’s most commonly owned rifles and an “unusual” weapon outside the Second Amendment.

If the Court says so, Massachusetts’ “assault-style firearm” ban may be living on borrowed time.