SOUTH PORTLAND (AP) — Marijuana advocates want to finally take their legalization drive — thus far the province of western states — to the Northeast, and they say the first state to do it here might be Maine.

The Pine Tree State has a long history with cannabis — Maine voters approved medical marijuana legalization 15 years ago, becoming the first state to do so in New England. Now, national marijuana advocates say, the state represents a chance for pro-marijuana forces to get a toe-hold in the northeastern states they have long coveted.

Supporters of marijuana legalization say part of their focus on Maine is schematic — the ease of Maine’s citizen-led public ballot initiative process makes it a more viable target than states where laws can only be changed through complicated state legislative battles. Pro-legalization advocates also cite a pair of recent victories in municipal legalization drives — Portland, the state’s largest city, in 2013 and South Portland, its fourth largest, this month.

Maine also decriminalized the possession of small amounts of marijuana nearly four decades ago, and the state already has a sizeable network of eight dispensaries and more than 1,500 legal growers. The favorable climate for legalization has national and local pro-marijuana groups gearing up for a potential statewide legalization ballot initiative in 2016.

“It’s quite possible that Maine could be the first state in the Northeast to legalize marijuana and other states would follow,” said Bill Piper, director of national affairs for the Washington, D.C.-based Drug Policy Alliance.

Marijuana reformers around the country scored a series of wins on election night, when Oregon, Alaska and Washington, D.C., all went legal. Maine supporters are already crafting the ballot initiative for the 2016 election cycle, according to David Boyer, a Falmouth resident and political director for the Washington-based Marijuana Policy Project.

The petitioners will need to collect about 61,000 signatures to get the item on the ballot, according to the state constitution. Boyer said the petition drive will likely begin in the next six months.

Maine does have some competition to be first to legalize in the Northeast, as national advocates are also targeting Massachusetts for a potential referendum in 2016. State legislatures in Rhode Island and Vermont could also take up the issue next year. Outside the Northeast, national advocates are also pushing for popular ballot initiatives in California, Arizona and Nevada.

Maine’s ballot initiative will face significant opposition from some public and law enforcement officials, some of whom campaigned against legalization in its cities. Some medical marijuana advocates also have reservations, including Hillary Lister, director of the Medical Marijuana Caregivers of Maine, who said she fears large-scale investors could crowd smaller growers out of the market.

Roy McKinney, director of the Maine Drug Enforcement Agency, said the legalization vote in South Portland — where voters approved a measure to allow people age 21 and older to possess an ounce of marijuana — doesn’t supersede state law. He said the agency’s stance on the statewide ballot initiative would depend on how it was written, but added that it opposed efforts to legalize marijuana via the state legislature.

Approval on a statewide level won’t sail through, as anti-marijuana forces are emboldened by a recent victory of their own — a November legalization referendum’s failure in Lewiston, the state’s second-largest city.

Lewiston Mayor Bob Macdonald, who worked in the drug unit of Lewiston’s police department before becoming mayor, called legalization a sign of “degeneration of society.” He said he is glad the referendum to legalize marijuana in his city failed.

“I’m set in my ways and that’s one thing I’m totally against — making any drugs legal,” he said.