The parents of a Portland woman who died after being shot in 2010 filed initial paperwork Monday for a statewide referendum that would require background checks on anyone purchasing firearms at gun shows or from private sellers.

Judi and Wayne Richardson of South Portland submitted a ballot initiative application with the Maine Secretary of State’s Office on behalf of the state chapter of Moms Demand Action for Gun Sense, a national gun-control organization that formed after the Sandy Hook Elementary School shooting in December 2012. The organization hopes to secure a spot on the November 2016 ballot for a referendum to close the “gun show loophole,” which critics contend allows convicted felons and the mentally ill to obtain guns without scrutiny.

“While nothing can bring back our daughter, we can and must take action to prevent other parents from going through the senseless pain and suffering of having a child or loved one taken by gun violence,” said Judi Richardson, the chief sponsor of the ballot measure, whose 25-year-old daughter, Darien, died after being shot with a gun that changed hands several times without background checks.

The proposed ballot question would ask Mainers whether they support expanding Maine’s current criminal background requirements to sales that occur at gun shows as well as in private, person-to-person transactions. In the latter case, private sellers would have to complete the transaction with a registered gun dealer who can run a background check through the federal system.

Moms Demand Action for Gun Sense would need to collect more than 61,000 signatures from Maine residents to qualify for the November 2016 ballot, which is likely to feature several high-profile ballot questions along with presidential, congressional and legislative races.

Maine law now requires commercial gun dealers and retailers to conduct background checks on buyers, but private sales are not covered. The FBI conducted 44,195 background checks primarily for dealers in Maine between Jan. 1 and July 31 this year, but there are unknown numbers of private sales that occur between acquaintances, outside of gun shows or in response to ads published through venues such as the weekly classified shopper Uncle Henry’s.

Gun control groups have lobbied hard at the state and federal level to require background checks on all gun sales, arguing that looser laws in states such as Maine help fuel an interstate black market for both guns and drugs. Those efforts have failed both in Augusta and Washington, D.C., in the face of stiff opposition from the National Rifle Association and gun rights groups.

OPPOSED BY SPORTSMAN’S ALLIANCE

David Trahan, executive director of the Sportsman’s Alliance of Maine, hadn’t yet read the full text of the proposed referendum, but said his organization has opposed past “universal background check” efforts. Trahan questioned how police would enforce the requirement on private, person-to-person sales and echoed concerns among staunch Second Amendment defenders that the record-keeping needed to meet the law would lead to a de facto national database or registry of gun owners.

Trahan portrayed the referendum as part of former New York City Mayor Michael Bloomberg’s national campaign to strengthen gun laws. The organization founded by Bloomberg, Everytown for Gun Safety, has worked closely with Moms Demand Action for Gun Sense.

“Maine has one of the highest per-capita gun ownership rates in the country and is one of the safety states in the country,” Trahan said. “This is part of a national agenda.”

Everytown and Moms Demand Action waged stiff campaigns to expand the federal requirements for background checks in the months after 20 elementary school children were killed inside the Sandy Hook Elementary School in Newtown, Connecticut. The background check expansion was among several gun control proposals that failed in the U.S. Senate after supporters were unable to muster the 60 votes needed to break a filibuster despite polls showing strong public support for the provision.

Similar efforts repeatedly failed in the Maine Legislature as well. For instance, a bill that would have increased the penalty for anyone who transfers a gun to someone prohibited from owning one died in the Legislature this year.

The background check referendum, if the signature-gathering campaign is successful, would further crowd what is expected to be a packed ballot in November 2016. Other organizations are collecting signatures for petitions to legalize marijuana, to increase Maine’s minimum wage and to ban asylum seekers from receiving General Assistance.

CLOSING LOOPHOLE, WITH EXCEPTIONS

The gun referendum would exempt family members – from immediate family down to first cousins and in-laws – from having to undergo a background check before a gun transfer. It also would contain exemptions to allow hunters to loan firearms to others, as long as the owner is present, and if a gun transfer was necessary “to prevent imminent death or prevent great bodily harm.”

Maine law requires at least five residents to sign an application for a ballot initiative. The Richardsons were joined on the application by Bucksport Police Chief Sean Geagan, Laurie Fogelman, who is involved in domestic violence issues, father and gun owner Christopher Dickens of Blue Hill, and mother Amy Fiorilli of Otis. The Richardsons have become involved in the gun control and gun safety debate in Maine and nationally in the years since their daughter died in a slaying that remains unsolved.

A graduate of Bowdoin College, Darien Richardson died in early 2010 from a blood clot caused by several bullet wounds she suffered weeks before when masked intruders burst into her Portland apartment.

The same .45-caliber handgun was later used by a different gunman to kill another man in Portland. But that shooter refused to say where he obtained the gun, and police were unable to trace the gun’s history because the original private seller was not required to conduct a background check.

“This ballot measure will close that loophole,” Judi Richardson said in a written statement. “It won’t stop all gun violence, but it will save lives and make it harder for dangerous people to get their hands on guns.”

MAINE GUNS IN OUT-OF-STATE CRIMES

Although Maine consistently has gun-violence rates that are among the lowest in the country, advocates for stronger gun control laws maintain the state is an exporter of guns used in crimes.

The U.S. Bureau of Alcohol, Tobacco and Firearms and Explosives regularly traces the origins of firearms that are recovered by police as part of an investigation. In 2014, 5.5 percent of the firearms recovered and traced by police in Massachusetts had originated in Maine, second only to New Hampshire as the top source state, according to ATF data. From 2006 to 2011, an average of 8.3 percent of the guns traced in Massachusetts had originated in Maine.

Opponents counter that criminals will find ways to get guns, and that universal background checks merely impose a burden on law-abiding gun owners.