Washington — The Supreme Court on Tuesday turned away a challenge to an Illinois law banning certain semi-automatic rifles and large-capacity magazines, leaving the measure intact.

The court declined to review a decision from the U.S. Court of Appeals for the 7th Circuit that preliminarily upheld Illinois’ prohibition on assault-style weapons. The challenge to the ban has been before the justices twice before, though in an emergency posture, and they have declined to block the law while legal proceedings played out.

Its rejection comes on the heels of the justices’ decision not to consider the constitutionality of a similar law from Maryland, though they were asked to weigh in before a federal appeals court has ruled. Ten states, including Illinois, and the District of Columbia have laws that prohibit the possession of certain assault-style weapons.

Justice Samuel Alito said he would have granted the bid to consider the ban’s constitutionality. In a separate statement, Justice Clarence Thomas noted that the case remains in the early stages and hopes the Supreme Court will consider the issues raised by the challengers after the 7th Circuit renders its final decision in the case.

“It is difficult to see how the Seventh Circuit could have concluded that the most widely owned semiautomatic rifles are not ‘Arms’ protected by the Second Amendment,” Thomas wrote.

The Illinois ban

Illinois passed its law outlawing semi-automatic “assault weapons” and large-capacity ammunition feeding devices in 2023, after a gunman killed seven people and wounded 48 at an Independence Day parade in Highland Park in 2022. Armed with an AR-15-style rifle and 30-round magazines, the suspected shooter fired 83 rounds in less than a minute, according to court filings.

The law bans specific guns including the AR-15 and AK-47, and it defines large-capacity magazines as those that hold more than 10 rounds for long guns and 15 rounds for handguns. Inoperable or antique firearms, air rifles and handguns are some of the weapons still legally allowed in the state.

Shortly after the law was signed in January 2023, six groups of Illinois residents, firearms sellers and gun rights advocacy groups challenged the restrictions on certain semi-automatic rifles and large-capacity magazines as a violation of the Second Amendment. In four of the cases, a federal district court in Southern Illinois agreed to block the ban, but in the remaining two, district courts refused to do so.

A three-judge panel on the 7th Circuit reviewed the decisions, and in a divided ruling, kept the weapons ban in place. Applying the Supreme Court’s framework announced in 2022, the appeals court said in part that there is a “long-standing tradition of regulating the especially dangerous weapons of the time, whether they were firearms, explosives, Bowie knives or other like devices” to protect public safety.

As part of this tradition, the 7th Circuit majority found, there is a long history of allowing the military and law enforcement to have access to “especially dangerous weapons,” while restricting civilians from owning them.

The panel wrote that it is “not persuaded that the AR-15 is materially different from the M16,” and noted that the Supreme Court has said those firearms can be regulated or banned.

The firearms banned under the Illinois law are “much more like machine guns and military-trade weaponry than they are like the many different types of firearms that are used for individual self-defense,” the 7th Circuit said, concluding that these semi-automatic rifles are not considered arms protected by the Second Amendment.

The challengers appealed the ruling to the Supreme Court, arguing that under the Illinois ban, law-abiding residents can’t have firearms that are owned by millions of Americans.

“The Seventh Circuit’s decision demonstrates a continuing refusal to follow this court’s Second Amendment precedents and manifests a continued distaste for, if not hostility towards, the people’s right to keep and bear arms,” lawyers for one group of plaintiffs, led by the group Gun Owners for America, wrote in a Supreme Court filing.

Another group of challengers, led by the National Association for Gun Rights, argued that laws banning weapons that are in common use for lawful purposes are “categorically unconstitutional.”

“If courts continue to operate under the misimpression that the right to keep and bear arms protects only neutered firearms like break-barrel shotguns and bolt-action hunting rifles, the Second Amendment will offer little but a parchment barrier against tyranny,” Gun Owners of America said in their filing.

But lawyers for the state urged the Supreme Court to turn away the dispute, which would leave the ban in place, because it is too soon for it to intervene.

“Courts are working with diligence and care to apply the text-and-tradition standard announced two years ago in Bruen to laws prohibiting civilian possession of assault weapons and [large-capacity magazines] — many of which have been on the books for decades. And, as the decision below demonstrates, they are doing so in a manner consistent with” the Supreme Court’s precedents, they said in a filing.

Illinois’s attorney general and solicitor general also noted that the 7th Circuit applied the Supreme Court’s history-and-tradition test, and determined that the features of certain semi-automatic weapons and large-capacity magazines are “unsuitable and unnecessary for civilian self-defense.”

The lower court’s decision, they said, “found that the tradition of restricting certain weapons for civilian use included a tradition of reserving some of them, if appropriate, to the military or law enforcement. That tradition is supported by many federal, state, and local laws.”