SOUTH PORTLAND, Maine — South Portland city voters on Nov. 4 will decide whether to join their neighbors across the Casco Bay Bridge in legalizing marijuana possession.

A citizen-initiated referendum question will ask whether residents are in favor of an ordinance that would make it legal for citizens 21 and older to recreationally use up to an ounce of marijuana.

A similar ordinance will be on the ballot for voter consideration in Lewiston, and one nominally legalizing possession of 2.5 ounces of the drug passed handily in Portland last November.

The proposed ordinance would also make the possession and use of associated paraphernalia legal, though it would not legalize public use, or the operation of any type of vehicle while under the influence of the drug.

The ordinance does not propose any form of taxation, the establishment of dispensaries, or any stipulations regarding the buying or selling of the substance.

It also would not change state or federal laws that prohibit the sale or possession of pot.

David Boyer, Maine political director for the Marijuana Policy Project, said he believes South Portland will pass the ordinance.

“Prohibition has been a failure,” he said. “It’s done nothing to stop the flow of marijuana into the communities.”

He added that “58 percent of Americans are ready to move forward with a more sensible marijuana policy,” citing a 2013 Gallup poll.

In July, proponents for legalization submitted a petition of over 1,500 signatures to the city, although only 959 signatures (5 percent of registered voters) were needed to qualify for the ballot.

Boyer said that, in his experience with South Portland residents, more people seemed for the ordinance than against it. Citizens over 65 are less likely to support it, he said, since they grew up in a time during which the war on drugs and government campaigns against drug use were ramping up.

Many senior citizens use the drug medicinally, but illegally, because they cannot afford a doctor or have a condition that is not covered for medicinal use, he said, noting that legalization would remedy that problem.

The ordinance cites six studies that found alcohol to be more harmful than marijuana.

“It’s illogical to punish adults for a substance that’s less harmful than alcohol,” Boyer said.

The ordinance also argues that “marijuana laws are disproportionately enforced against communities of color.”

The text cites a 2013 report produced by the American Civil Liberties Union, which states that “African Americans in Maine are more than two times more likely to be arrested for marijuana possession than white citizens are, despite similar rates of consumption.”

In addition, the ordinance suggests that police officers’ time could be better spent addressing more serious offenses, including violent crimes or property crimes.

After the November election, win or lose, Boyer said, the MPP will commence a statewide initiative for inclusion on the 2016 ballot.

For the last 20 to 30 years, he said, there’s been no “sane” message about marijuana. It’s difficult to overcome years of propaganda and fear, but Boyer pointed to Colorado’s decision to legalize marijuana as evidence that it’s possible.

“Look at Colorado,” he said. “The sky hasn’t fallen there.”

Boyer said the MPP is all for promoting responsible use, just as Colorado has done. Billboards in Colorado, Boyer said, use the slogan “start low, take it slow” to encourage safe use.

“Fear mongering and scare tactics don’t work,” Boyer said. “Having conversations does.”

This is the farthest extent to which marijuana policy can be pursued at the local level, but Boyer said the MPP and the ordinance will “direct law enforcement to use discretion and respect the will of the voters” instead of continuing to aggressively enforce state or federal laws against the drug.

However, South Portland Police Chief Edward Googins opposes the ordinance.

“The issue for me as a police chief is that the initiative is not a good thing for our community or anywhere else,” Googins said.

Marijuana is a controlled substance that affects the way a person thinks and acts, he said. Colorado’s legalization, according to Googins, is an example of a “failed public policy experiment.”

The number of cases of people operating vehicles while under the influence, as well as the number of emergency room visits, has increased dramatically since the state’s 2012 decision, he said. Googins is worried, too, about the city’s younger citizens and their access to the drug.

According to the chief, pot is dangerous because it “continues to create and perpetuate other problems” in society.

“Claims that marijuana is safer than alcohol are so bogus it’s not even funny,” he said.

City councilors unanimously passed a nonbinding resolution opposing legalization in early June, and also expressed disapproval at a press conference. Their main concern was the effect that legalization would have on children, and that legalizing the drug adds little benefit to the community.

Last year in Portland, 67 percent of voters supported an ordinance allowing adults 21 and over to use or possess up to 2.5 ounces of recreational marijuana.

Following that success, the MPP pursued initiatives in South Portland, York and Lewiston. The question will be on the November ballot in Lewiston; York’s selectmen voted twice not to put it on the town ballot, and their action was upheld in court.