Emily Snyder, spokeswoman for the attorney general, said Ms. Healey’s office has not reviewed or approved any bylaws to ban medical marijuana dispensaries. However, she pointed out a 2013 decision by former Attorney General Martha Coakley’s office that disallowed an attempt by Wakefield to ban medical marijuana dispensaries from opening in that town. Wakefield’s argument was that not allowing the ban would force the town to violate the federal law that classifies marijuana as a controlled substance.

Margaret J. Hurley, assistant attorney general and director of the Municipal Law Unit under both Ms. Coakley and the current attorney general, deemed Wakefield’s proposed bylaw invalid, saying it conflicted with the state statute.

She said the law “could not be served if a municipality could prohibit treatment centers within its borders, for if one municipality could do so, presumably all could do so … The question is not whether a ban in Wakefield alone would make it impossible for there to be ‘one treatment center … in each county.’ The question is whether the legislative purpose of reasonable access to treatment centers could be achieved if every municipality banned them.”