Massachusetts lawmakers are currently considering a bill to legalize recreational marijuana. If they fail to pass the measure, there's a good chance that the proposal will go before voters as a ballot question in November. With this in mind, a trio of state leaders - Governor Charlie Baker, Attorney General Maura Healey, and Boston mayor Marty Walsh - published an op-ed in the Boston Globe voicing their opposition to marijuana legalization. In it, they cited what they say is the negative impact that widely available recreational marijuana has had on Colorado, where residents have been able to buy the drug legally since 2014. WGBH All Things Considered host Barbara Howard spoke with Colorado Public Radio reporter Ben Markus about how legalized marijuana has affected that state.