In a 2016 file photo, Attorney General Maura Healey is interviewed at the T&G offices. [T&G File Photo/Christine Peterson] ▲ In July 2016, gun rights advocates stand outside the Statehouse in Boston over Attorney General Maura Healey's crackdown on assault weapons. [File Photo/Mike P. Norton/SHNS] ▲

WORCESTER – Attorney General Maura T. Healey is expected Thursday to request a stay of a federal lawsuit over her 2016 crackdown on "copycat" assault weapon sales, arguing a delay is justified until a related suit in state court is resolved.

The move, announced in federal court in Worcester Wednesday, drew criticism from the plaintiffs, two of whom say they have shut down retail operations as a result of what they see as politically motivated executive overreach.

"She's doing everything she can to stop the case from moving forward ... because they cannot defend the indefensible," Lawrence Keane, general counsel for the National Shooting Sports Foundation, alleged Wednesday.

Regardless of whether the ban is upheld, it appears to be having the desired effect.

"Sales of assault weapons covered by the ban have effectively stopped since our enforcement of the ban and we have not prosecuted anyone," a spokesman for Ms. Healey wrote in an email Wednesday.

When she initiated the controversial enforcement notice in July 2016, Ms. Healey contended that 10,000 illegal "copycat" assault rifles had been sold statewide the prior year.

She charged that gun manufacturers, by making small tweaks to guns, had been violating the intent of the law, and threatened criminal prosecution of retailers who, from that point forward, sold guns that failed to pass an enumerated two-prong test.

"The gun manufacturers have marketed these weapons as the legal version of a prohibited gun, but I want to be clear: these weapons are illegal, they are copies or duplicates of banned weapons, and they cannot be bought or sold here in Massachusetts," she said at the time.

NSSF, a large firearms trade association, joined four state gun shops, including Pullman Arms of Worcester, in suing Ms. Healey a month later over the announcement, alleging that it was overly vague and exceeded her authority.

"She can't even interpret her own enforcement notice," Mr. Keane alleged, saying that dealers who reached out with questions on specific firearms were told to use their "best judgment."

Two of the four gun shops in the lawsuit, Pullman Arms of Worcester and Grrr! Gear of Orange, have stopped retail sales as a result of declining sales attributed to the enforcement notice, Mr. Keane said.

The announcement, although supported in 2016 by state district attorneys, drew criticism from other officials.

Republican Gov. Charlie Baker and his administration wrote letters of concern over perceived ambiguity in the notice, while 58 lawmakers, including 18 Democrats, sent Ms. Healey a letter objecting to her action "in the strongest possible terms."

Ms. Healey stood her ground, and the Worcester lawsuit has moved slowly. U.S. District Court Judge Timothy S. Hillman in March 2018 denied a motion to dismiss that Ms. Healey had filed 14 months prior, and Ms. Healey appealed a portion of that denial to the U.S. Court of Appeals.

The court heard arguments on the appeal on Jan. 9 and denied it within hours.

"I've never seen that in my 30 years practicing law," Mr. Keane said, alleging the appeal was "frivolous" and a "stall tactic."

A spokesman for Ms. Healey characterized the appeal differently, saying it was dismissed "only because the other side made a concession in open court that they had refused to make before the district court."

The disagreement concerns an argument Ms. Healey made that part of the claim alleged an abuse of state law that could not be brought in federal court. Mr. Keane objected to the implication that his lawyers made a concession, saying that neither of the counts in their amended lawsuit has been dismissed.

"They're trying to mischaracterize the complaint to create this false basis to appeal," Mr. Keane said. "They didn't succeed."

Assistant Attorney General Julia E. Kobick said Wednesday said she intends to file a motion Thursday asking the case to be stayed while a related case is heard in Suffolk Superior Court.

Baystate Firearms of Peabody and Cape Gun Works of Hyannis are also suing the AG over the enforcement notice, arguing that a court should render it invalid because it constitutes an improperly created regulation.

Ms. Kobick argued Wednesday that the Worcester case should be stayed until the Baystate case is resolved.

Should Baystate prevail, she reasoned, the lawsuit in Worcester would be moot because the enforcement notice would be invalid.

When Judge Hillman remarked that the Worcester case has already been moving slowly, Ms. Kobick asserted that it was "not in (Ms. Healey's) interest to keep prolonging these cases."

Mr. Keane disagreed, and slammed Ms. Healey as threatening gun dealers with criminal prosecution based on an ill-defined, "transparently political" enforcement notice.

He noted that the July 20, 2016, press conference came five days before the Democratic National Convention.

The conference, as Ms. Healey noted at the time, also came a month after a gunman in Orlando killed 49 people at a night club with an assault rifle.

"Study after study has shown that gun laws work," then-Suffolk County District Attorney Dan Conley said at the announcement, applauding Ms. Healey for her action.

Also supporting Ms. Healey that day was Greg Gibson, a Gloucester veteran whose son, Galen, was killed in a school shooting in 1992.

"I wholeheartedly support this initiative and every other initiative that we can come forward with that will save other families from having to endure what my family suffered," he said.

A federal judge in Boston last April denied a separate legal challenge to Ms. Healey's enforcement notice filed by, among others, the Gun Owners' Action League of Northboro.

That case is under appeal.

The enforcement notice does not apply to individual gun owners who transfer banned weapons bought before the July 20, 2016 notice date.

This story has been updated to clarify the attorney general's enforcement options.

Contact Brad Petrishen at brad.petrishen@telegram.com. Follow him on Twitter @BPetrishenTG.