The U.S. Supreme Court indicated Tuesday it would hear arguments possibly later this year over Cook County’s ban on so-called assault weapons and a similar law in Connecticut, a precursor to what could be a sweeping ruling on the constitutional right to own such firearms.
The Cook County case stems from a lawsuit by three county residents and two gun rights organizations against county officials, alleging the county’s assault weapons ban — which includes prohibitions on the AR-15 and similar semiautomatic rifles — violates the Second and Fourteenth amendments.
Cook County State’s Attorney Eileen O’Neill Burke vowed to “not back down” from defending the ordinance, saying assault weapons “have no place in our communities.”
“Countless victims have already endured the devastating impact of gun violence,” she said in a statement after the court declared it would hear arguments in the case. “We will defend this lawful ordinance before this nation’s highest court to continue protecting the people of Cook County.”
The ordinance applies to more than 100 rifles, shotguns and pistols, and it prohibits the sale, manufacture, loan, transfer, acquisition or possession of those weapons, as well as large-capacity ammunition magazines that generally hold more than 10 rounds.
Some exemptions exist, including for law enforcement and the armed forces, but violations can bring fines of $5,000 for a first offense, $10,000 for a second offense and up to six months in jail.
Illinois’ own ban also at stake
The Cook County case is separate from another lawsuit before the U.S. 7th Circuit Court of Appeals in Chicago challenging the constitutionality of Illinois’ statewide ban on assault weapons and high-capacity magazines — but a ruling in the Cook County case could directly shape that one.
The state law, which bans all or most of the same weapons as the Cook County ordinance, has been in effect since January 2023 when Democratic Gov. JB Pritzker signed it following the mass shooting at a Highland Park Independence Day parade in 2022 that killed seven people and wounded dozens more.
The state’s gun ban has so far withstood legal challenges. But two years ago, U.S. Supreme Court Justice Clarence Thomas wrote that the high court should review Illinois’ law, expressing deep reservations about its constitutionality.
“In my view, Illinois’ ban is ‘highly suspect because it broadly prohibits common semiautomatic firearms used for lawful purposes,’” Thomas wrote, citing case law to bolster his position.
It’s unclear what impact a favorable Supreme Court ruling for the Cook County plaintiffs could have on Illinois’ law. But U.S. District Judge Rebecca Pallmeyer, who ruled in 2024 in favor of Cook County, acknowledged that “plaintiffs assert, a ruling in their favor concerning the county’s ban would strongly imply that the state ban is also unconstitutional.”
David Sigale, an attorney for the Illinois State Rifle Association, likewise said he thinks a Supreme Court ruling in favor of the plaintiffs in the Cook County case would “have an enormous impact” on the Illinois case.
“It’s the same law,” Sigale said. “If the Supreme Court decides in that case that these firearms are protected by the Second Amendment, I mean that answers the question.”
In defending the state’s ban, Illinois Attorney General Kwame Raoul’s office has so far successfully argued that the prohibited weapons are not considered “arms” under the Second Amendment and share the same qualities as military weapons that are not commonly used for self-defense.
Republican President Donald Trump’s administration is not party to the case, but Harmeet Dhillon, the U.S. Justice Department’s assistant attorney general for civil rights, argued before the 7th Circuit in September that the nation has a “strong interest” in ensuring the Second Amendment’s right to bear arms is “not relegated to a second-class right.” She criticized Illinois officials’ claims that guns covered by the state ban are better suited to military operations than routine self-defense.
The 7th Circuit has not ruled in the case, which is being heard by the panel after a Trump-appointed federal district judge in southern Illinois found the state gun ban unconstitutional.
Broader landscape
Similar laws are in place in about a dozen states, covering major cities including New York, Los Angeles and Washington, D.C. Congress allowed a national assault weapons ban to expire in 2004, but Democrats have supported renewing it in response to a series of mass shootings.
Connecticut’s law, for example, was passed after a mass shooter used an AR-15 to kill 26 children and educators at Sandy Hook Elementary School in 2012. The state argues the guns are a preferred weapon of mass shooters and can be banned because they are similar to military-grade weapons.
“Assault weapons cause massive devastation,” said Janet Carter, managing director of Second Amendment litigation at Everytown Law, which has also pushed in Illinois to require some gun manufacturers to redesign pistols so they can’t easily be converted into automatic weapons. “These laws are critical public safety measures, and they are consistent with the Second Amendment.”
Gun rights groups, on the other hand, argue it’s unconstitutional to ban semiautomatic rifles, which are legally owned by millions of Americans.
Adam Kraut, executive director of the Second Amendment Foundation, one of the groups challenging the Cook County law, said in a statement that the Supreme Court hearing on the cases will provide “necessary guidance.”
“The modern semi-automatic rifles banned in Cook County, Connecticut and elsewhere are among the most commonly owned firearms in the country, placing them well within the scope of the Second Amendment,” Kraut said. “The Second Amendment protects arms in common use for lawful purposes, and it’s hard to argue that a type of rifle that potentially outnumbers Ford F-150 trucks in America doesn’t meet that standard.”
‘High’ stakes
The plaintiffs’ argument in the Cook County case rests on a few landmark Second Amendment rulings, chief among them the Supreme Court’s 2022 decision in New York State Rifle & Pistol Association v. Bruen, which greatly expanded Second Amendment rights.
In the case, a 6-3 conservative majority ruled that modern gun laws must be rooted in the nation’s historical tradition of firearm regulation. Key to that determination is whether gun laws are historically consistent with laws on the books in the 18th century, when the Second Amendment’s right to bear arms was ratified.
The Cook County plaintiffs argue the banned weapons are in “common use” in everyday society, and therefore protected.
In 2024, Pallmeyer ruled in favor of the defendants — Cook County, Sheriff Tom Dart, Board President Toni Preckwinkle and then-State’s Attorney Kim Foxx. The plaintiffs appealed to the 7th Circuit, which ruled against them, arguing they “failed to develop a record” to support a favorable ruling.
Darrell Miller, a law professor at the University of Chicago, said the stakes for any Second Amendment case are “high” since the Bruen decision.
“Every time (the court) writes an opinion applying the Bruen test, the consequences expand beyond the discrete regulation being challenged,” Miller said.
Miller said there’s some indication the high court and particularly some of the conservative justices are “very much in the Second Amendment rights-protecting frame of mind,” but that because assault weapons bans are such a politically fraught issue, it’s difficult to predict an outcome.
He said there’s uncertainty on where Justice Amy Coney Barrett or Chief Justice John Roberts would land.
“It’s not a fait accompli in any way,” Miller said. “Of the people that I’m in conversation with, some see this as an opportunity for the court to hold that these bans are unconstitutional, but some are a little less optimistic or pessimistic, depending on your politics, about where the court’s going to land on this.”
The Supreme Court backed Second Amendment rights in two cases this term, striking down gun carry restrictions in Hawaii and a broad federal ban on gun ownership by marijuana users. The high court has previously upheld some restrictions, including a law barring people under domestic-violence restraining orders from having guns.
The Associated Press contributed reporting.
