The group pushing for Massachusetts voters to legalize recreational marijuana says Alex Morse of Holyoke is the first mayor in the state to endorse the ballot question.

Morse says — for him — the issue is in part about criminal justice reform.

“One of the advantages of being a state that isn’t the first in implementing this is that we can learn from both what’s worked in places like Colorado but also what hasn’t worked,” Morse says.

Most of Massachusetts’ top government leaders oppose legalizing marijuana — including Governor Charlie Baker, Attorney General Maura Healey, House Speaker Bob DeLeo and Boston Mayor Marty Walsh.