SOUTH PORTLAND — Maine might soon be going to pot.

Ballot questions about the legalization of marijuana in two Maine cities are a run-up to a statewide legalization drive in 2016, pro-marijuana activists say. They hope success in Tuesday’s election is a bellwether for a statewide vote to legalize the drug. Pro-pot activists are also following the votes to check on the prospects of Maine becoming the third state in the nation to legalize.

People in South Portland and Lewiston will vote on ballot initiatives that would legalize possession of marijuana. Activists also tried to get a question on the ballot in York but were denied by the town’s Board of Selectmen.

The ballot initiatives are designed to “build support in advance of our 2016 statewide initiative,” said David Boyer, Maine political director for the Washington, D.C.-based Marijuana Policy Project. He said the statewide petition drive would likely take place in 2016 so the marijuana referendum would be on the ballot during a high-turnout presidential election year.

“We haven’t been shy about our plan to do a statewide initiative that would tax it in the same way as alcohol and tobacco,” Boyer said. “Marijuana is being sold every day in these communities. Is it going to be by drug dealers, or by licensed dealers?”

The petitions call for the municipalities to allow people age 21 and older to possess an ounce of marijuana without facing any penalty. Portland voters overwhelming approved a similar law in their city last year. It remains illegal to buy or sell marijuana or smoke it in public.

But not everyone is so high on the idea. Law enforcement officials are adamant that marijuana possession remains illegal throughout Maine under state law. Possession of marijuana under 2.5 ounces is a civil violation and 2.5 ounces to a pound is a misdemeanor. More than that can be a felony charge for possession with intent to distribute.

“Officers are duty bound to enforce state law, so long as that’s on the books, it’s a law that will be enforced,” said Roy McKinney, director of the Maine Drug Enforcement Agency.

Officials in South Portland, Lewiston and York also have spoken out against legalization. Lewiston Mayor Robert Macdonald said he opposes legalization and city police will continue enforcing laws if it passes.

“It can pass, but if you light up out there, you’re going to get summonsed, just like now,” he said. “Nothing’s going to change, except in your mind it’s going to be OK.”

A 2013 Public Policy Polling poll said Maine residents think marijuana usage should be legal in the state by a 48 to 39 margin. Senior citizens were the only group opposed to it, while every other age bracket supported it by at least 15 percent.

State Rep. Diane Russell, who has made a handful of attempts to legalize marijuana through state legislation, said legalizing marijuana through a patchwork of city and town laws is not the right approach.

“I have no question that we will be legalizing. The question is when and how,” the Portland Democrat said. “Maine will be legalizing marijuana whether you like it or not, the question is whether we do it responsibly.”

Statewide legalization votes, and another in Washington, D.C., are planned in Oregon and Alaska this fall. They would join Colorado and Washington if passed.

The Maine city votes “will definitely give us a good read on where the public sentiment is” in the state, said Erik Altieri, spokesman for NORML, a nationwide pro-marijuana advocacy group.