PORTLAND — Access to marijuana among children and the economic impact of the drug were among points of contention Monday as top advocates for and against pot legalization took part in a campaign-style debate in Portland.

David Boyer, head of the Campaign to Regulate Marijuana Like Alcohol, squared off against Scott Gagnon, Maine director of Smart Approaches to Marijuana, in the point-counterpoint forum hosted by the Maine Law Federalist Society.

The debate, which attracted a crowd of about 60, took place at the University of Maine School of Law.

The topic comes as at least four simultaneous efforts are underway to legalize recreational use of marijuana by adults statewide.

Boyer’s group and another called Legalize Maine are collecting signatures to force potentially competing statewide ballot questions on the subject, with both aiming to legalize the drug, but with differences in who would regulate growth and distribution of marijuana, among other things.

Meanwhile, Democratic state Reps. Mark Dion and Diane Russell, both from Portland, are each promoting bills that would make possession of pot legal — although Dion’s legislation would let municipalities decide locally whether to allow it, while Russell’s would trigger a statewide vote in 2016.

Boyer, as Maine political director of the Marijuana Policy Project, was behind successful campaigns to pass ordinances in Portland and South Portland nominally legalizing pot possession — although he had less success in Lewiston and York, where voters rejected a similar ordinance and town officials refused to put it on the ballot, respectively.

During the debate Monday, Boyer reiterated a case he made in those previous campaigns, that marijuana is safer than alcohol and should be legalized — and regulated — similarly.

“It’s illogical to punish adults who would rather use the safer substance,” said Boyer.

He argued that legalizing and regulating the drug would take distribution — and revenues — out of the hands of drug dealers, who have incentives to hook customers on stronger and more dangerous drugs.

But Gagnon, who writes a public health blog for the Bangor Daily News, said efforts to legalize the drug make it seem less dangerous to children. He said more minors abuse alcohol than any other substance, so regulating marijuana the same way would lead to similarly poor results.

“Whenever perception of risk of any drug decreases, use increases,” Gagnon said. “When they hear ‘safer than alcohol,’ they hear ‘it’s safe.’ It doesn’t matter what they’re saying, it’s about what (young people) are internalizing.”

Colorado’s rate of youth marijuana use climbed from 14th in the country to third since that state legalized recreational use in 2012, he said.

Gagnon also rejected Boyer’s argument that legalization could be a financial boon for Maine because pot would be taxed like alcohol. He said that for every $1 in tax revenues Maine makes off alcohol, it pays $10 in social costs, like health care and law enforcement.

“The pocket change we’d get from taxing marijuana wouldn’t cover the costs to our state,” he said. “The idea that regulation is somehow going to wrap its arms around this and control it is interesting.”

But Boyer said that while marijuana should be regulated like alcohol, it doesn’t have nearly the same societal costs — most marijuana products are not carcinogens like legal cigarettes, and they don’t typically trigger violent behaviors or fatal overdoses, he said.

“Even the most potent marijuana couldn’t kill you, while you could drink a bunch of wine coolers and die,” he said.

Boyer said Colorado collected nearly $60 million in new tax revenues and licensing fees from marijuana sales last year without the same downside as legal alternatives, like alcohol.

“That’s $60 million that didn’t go to drug dealers,” he said. “They’re building schools with that money.”

Boyer’s group and Legalize Maine continue to collect signatures with a goal of placing the question before Maine voters in the 2016 general election ballot. The Legislature has yet to take action on Dion’s or Russell’s proposed legislation.