PORTLAND, Maine (AP) — A coalition of gun groups has filed a lawsuit claiming that Maine’s new 72-hour waiting period for firearms purchases is unconstitutional and seeking an injunction stopping its enforcement pending the outcome of the case.

The lawsuit filed on behalf of five individuals contends that it’s illegal to require someone who passed a background check to wait three days before completing a gun purchase, and that this argument is bolstered by a 2022 U.S. Supreme Court ruling that changed the standard for gun restrictions.

“Nothing in our nation’s historical tradition of firearm regulation supports that kind of ‘cooling-off period’ measure, which is a 20th century regulatory innovation that is flatly inconsistent with the Second Amendment’s original meaning,” the plaintiffs’ attorneys wrote in the federal lawsuit filed Tuesday.

Maine is one of a dozen states that have a waiting periods for gun purchases. The District of Columbia also has one. Democratic Gov. Janet Mills allowed Maine’s restriction to become law without her signature. It took effect in August.

Maine’s waiting period law was one of several gun control measures the Democratic-controlled Legislature passed after an Army reservist killed 18 people and wounded 13 others in the state’s deadliest shooting in October 2023.

RELATED COVERAGE Maine elections chief who drew Trump’s ire narrates House tabulations in livestream Ranked voting will decide a pivotal congressional race. How does that work? Ranked voting tabulation in pivotal Maine congressional race to begin Tuesday

Laura Whitcomb, president of Gun Owners of Maine, said Wednesday that the lawsuit is being led by coalition of her group and the Sportsman’s Alliance of Maine, with assistance from the National Shooting Sports Foundation.

She and other critics of the waiting period law have pointed out that there are certain situations where a gun purchase shouldn’t be delayed, such as when a domestic violence victim wants to buy one. Maine hunting guides have also pointed out that someone who’s in the state for a short period for legal hunting may no longer be able to buy a gun for the outing.

The plaintiffs include gun sellers and gunsmiths who claim their businesses are being harmed, along with a domestic abuse victim who armed herself because she didn’t think a court order would protect her. The woman said she slept with a gun by her side while her abuser or his friends pelted her camper with rocks.

Nacole Palmer, who heads the Maine Gun Safety Coalition, said she’s confident that the waiting period law will survive the legal challenge.

The bill’s sponsor, state Rep. Peggy Rotundo, D-Lewiston, said half of Maine’s 277 suicides involved a gun in the latest data from 2021 from the Center for Disease Control and Prevention, and that she believes the waiting period law will reduce the number of suicides by firearm.

“I am confident that the 72-hour waiting period will save lives and save many families the heartbreak of losing a loved one to suicide by firearm,” she said.