A group led by Lt. Gov.
In a report provided to The Times, the group lists dozens of areas of inquiry, including how marijuana should be taxed, how to assess drivers under the influence of the drug and how it could be advertised and sold to consumers without increasing use by teenagers.
"We've said all along, we have to be accountable and responsible for making sure that we address the intended and unintended consequences of any effort to legalize, tax and regulate marijuana for adults," Newsom said in an interview. "It's not good enough to put something on the ballot and begin after the fact to ask those questions. We need to have some answers in mind before we present it to voters."
The effort appears aimed at assuaging concerns that have arisen since the state legalized medical marijuana in 1996 and the rocky rollout in a handful of states that have legalized recreational marijuana more recently.
Newsom, who is running for governor in 2018, is the highest-ranking state official to support the legalization of marijuana, though he professes to never have smoked it and says he hates the smell.
Though Newsom's support for legalization puts him at odds with Democrats such as Gov. Jerry Brown and U.S. Sen. Dianne Feinstein, Californians are increasingly supportive of marijuana legalization.
A Public Policy Institute of California poll released Wednesday reported that 53% of the state's residents said marijuana should be legal, while 45% said it should be not. That's the highest support for legalization since the PPIC began asking the question in 2010.
Newsom chairs the group that authored the report, a collection of medical, law-enforcement and civil-rights experts brought together by the American Civil Liberties Union of Northern California in 2013 to study the potential effects of legalization.
The 18-page report concentrates on three areas of further study: children, public safety and taxation/regulation. The panel plans to hold forums to solicit public comment in Los Angeles in April, San Francisco in May and Fresno in June, before announcing a set of policy recommendations by August.
Newsom pointed to the experience in other states that have legalized marijuana recently, notably Colorado, to argue that it was critical to do "granular" advance work before a legalization effort is undertaken in California.
"I don't take any of this lightly, and I think anyone advocating for this change needs to – we really need to be thoughtful about this. I want tough, I want sensible regulations," he said. "With respect to these other states, this is California…. It's very different than the other states. The magnitude, the scope of change here means we will have repercussions beyond our border, and we have to do it right."