The US Supreme Court declined on Monday to hear a challenge to a Democratic-backed ban in Maryland on assault-style rifles such as AR-15s, steering clear of the dispute while the litigation continues in a lower court.
The justices turned away an appeal by commercial firearms dealers, gun rights groups and several Maryland residents who have argued that the ban violates the right to keep and bear arms under US Constitution's Second Amendment.
The challengers had asked the Supreme Court to decide the legality of the ban before the Richmond, Virginia-based 4th US Circuit Court of Appeals issues a ruling in the case.
Other appeals still pending before the Supreme Court seek to challenge a similar law in Illinois banning assault rifles and large-capacity ammunition magazines. The justices did not act on those cases on Monday.
The availability of assault rifles, which are popular among gun enthusiasts, continues to fuel fierce debate in a nation bitterly divided over how to address firearms violence including frequent mass shootings.
The Supreme Court, which has a 6-3 conservative majority, has taken an expansive view of Second Amendment rights.
In 2022, the court recognized a constitutional right to carry a handgun in public for self defense in a decision that struck down New York state gun limits on carrying concealed firearms.
The court is expected to rule by the end of June in two major cases that implicate gun rights. One involves a challenge to a federal law barring people under domestic violence restraining orders from having guns. The second is a challenge to a federal ban on "bump stocks" - devices that enable semiautomatic weapons to fire rapidly like machine guns.
Maryland in 2013 enacted its ban on "military-style assault rifles" such as the semiautomatic AR-15 and AK-47, after a shooter used such a weapon in the 2012 mass killing of 20 children and six adults at Sandy Hook Elementary School in Newtown, Connecticut.
The Maryland plaintiffs - residents seeking to buy the banned weapons, a firearms dealer called Field Traders and three gun rights groups including the Second Amendment Foundation - sued the state in 2020.
Contesting the term "assault weapon" as an inaccurate "political term," the Maryland plaintiffs said that assault weapons cannot be outright banned because they are in "common use" by millions of law-abiding people.
The 4th Circuit dismissed their case based on a 2017 ruling by that same court that had upheld Maryland's ban after concluding that, under the Supreme Court's 2008 precedent, assault weapons are not protected by the Second Amendment because they are like "weapons of war" that are most useful in military service.
After the Supreme Court's 2022 ruling in the New York case, the justices asked the 4th Circuit to revisit the case made by the Maryland plaintiffs. The 4th Circuit decided in January to rehear the matter before its full slate of judges, and that remains pending.