PORTLAND — Voters will be asked to enact an ordinance that would legalize possession of up to 2.5 ounces of marijuana and paraphernalia.

It would not legalize the sale or purchase of marijuana, but would allow one to “engage in activities for the purposes of ascertaining the possession of marijuana and paraphernalia.”

That murky wording was chosen specifically to allow anyone arrested for possession — should the ordinance pass — to be able to mount a legal defense in court, City Councilor David Marshall has said.

The ordinance would prohibit recreational use of marijuana in public spaces, on school grounds or in transportation infrastructure. It also gives landlords the power to prohibit tenants from using marijuana on their property.

Police would still be authorized to cooperate with federal drug agents.

It also prohibits use by minors under the age of 21.

The ordinance also requires the mayor to issue an annual report to the full council about marijuana enforcement in the city.

The ordinance would also proclaim that the city officially supports the taxation and regulation of marijuana by the state and federal governments.

The Maine Green Independent Party led the initial petition drive to put Question 1 to voters, collecting more than 2,500 signatures.