Maine has joined 15 other states in a lawsuit against the Trump administration over its plan to allow the sale of forced-reset triggers, which make semiautomatic guns fire more rapidly, and return already seized devices to their owners.

The suit announced Monday argues that returning the triggers would violate federal law, pose a threat to residents and law enforcement, and worsen gun violence. It was filed in federal court in Maryland.

The complaint cites the high gun-related deaths in 2023, including 200 in Maine. That year, a mass shooting in Lewiston left 18 people dead and at least 13 others injured.

There have been several legal battles over the devices, which replace the typical trigger on an AR-15-style firearm. Maine lawmakers have also taken steps to try to ban similar rapid-fire devices.

The Biden administration had previously argued the triggers qualify as machine guns under federal law because constant finger pressure on the triggers will keep the gun firing, essentially creating an illegal machine gun.

Rare Breed Triggers, which makes the devices, had argued that the Bureau of Alcohol, Tobacco, Firearms and Explosives was wrong in its classification and the company ignored demands to stop selling the triggers until it was sued by the Biden administration.

Now under the Trump administration, the Justice Department reached a deal announced last month with Rare Breed Triggers to allow sale of forced-reset triggers to resume. The company was previously represented by David Warrington, Trump’s current White House counsel.

Under the settlement, Rare Breed Triggers agreed not to develop such devices to be used on handguns, according to the Justice Department. The settlement also requires the ATF to return triggers that it had seized or that owners had voluntarily surrendered to the government.

The states’ lawsuit is being led by the attorneys general of Delaware, Maryland and New Jersey. Besides Maine, the other states involved are Colorado, Hawaii, Illinois, Massachusetts, Michigan, Minnesota, Nevada, Oregon, Rhode Island, Vermont, Washington, along with the District of Columbia. The attorneys general in those states are all Democrats, though the office in Hawaii is technically nonpartisan.

A spokesperson for Maine Attorney General Aaron Frey declined Wednesday to comment on the lawsuit outside of what’s written in the complaint. The action, though, fits into a larger political picture in Maine where Democratic lawmakers have ramped up efforts to restrict gun use in the state, and faced heavy opposition from gun rights groups.

The deadly attack in Lewiston spurred several proposed state laws in 2024, including efforts to ban bump stocks, another accessory that lets gun users fire faster.

But Gov. Janet Mills vetoed that bill last spring. She said at the time that she was concerned that the ban would be impacted by pending U.S. Supreme Court decision on the constitutionality of a Trump-era bump stock ban. The national ban was overturned in June 2024, about two months after Mills’ veto.

State lawmakers are again considering a similar proposal this session. It left the Judiciary Committee with a divided report and has yet to be considered by the full House and Senate.

Another recent law passed in the wake of the Lewiston shooting that created a three-day waiting period for firearm purchases is currently on pause after gun rights advocates sued the state in federal court.

Mainers are also poised to vote on a citizen’s initiative to enact a red flag law, which would make it easier to temporarily remove access to firearms from people who are in a crisis. Though the issue will go to voters, Democrats agreed to hold a public hearing at the Legislature Wednesday following pressure from Republicans and gun groups.

Staff Writer Emily Allen contributed to this report.