Give Lt. Gov. Gavin Newsom credit. He speaks with passion, particularly on issues of social justice. And, to him, that’s what Proposition 64 is all about.

During a meeting with The Press Democrat Editorial Board Tuesday, Newsom said of the 8,800 arrests for nonviolent marijuana felonies last year, a disproportionate number of them involved African-Americans and Latinos: “We are still arresting and incarcerating folks that don’t look like me.”

It’s a compelling argument, one that underscores many of the inequalities of the criminal justice system. But it’s not enough to warrant the acceptance of a poorly worded ballot proposition that opens the door to a number of social problems and unknowns — and potentially puts local growers at a competitive disadvantage in a world where the recreational use of marijuana is legal.

We accept that legalization is probably an inevitability in California. But this is neither the right time nor the right proposition to make that happen. Here are several reasons why.

First, despite Newsom’s concerns, efforts have already been underway for years to decrease the number of nonviolent offenders in state prison and to ease up on the prosecution of marijuana offenses. It’s one reason why voters in 1996 approved Proposition 215 legalizing the medicinal use of cannabis and why then-Gov. Arnold Schwarzenegger decriminalized marijuana possession in 2010. According to the state Department of Corrections and Rehabilitation, not a single individual among the roughly 112,000 now in state prison is serving time for marijuana possession.

Second, the timing is bad. Led by two local legislators, state Sen. Mike McGuire and Assemblyman Jim Wood, the state Legislature last year approved and the governor signed the Medical Marijuana Regulation and Safety Act, which, for the first time in 20 years, established a regulatory framework and tax system governing sales and distribution of medicinal marijuana. These rules are late in coming, but they are a game-changer. Both Santa Rosa and Sonoma County are in the process now of vetting their permitting systems. But much of that work could be steamrolled by the approval of Proposition 64, which would likely leave the future of medicinal marijuana sales in limbo. It would be far better to let the MMRSA system play out and learn from it before moving ahead with legalization.

Third, given how Proposition 64 is worded, local growers have reason to be concerned about whether they will be put at a competitive disadvantage. For example, the proposition’s commercial cultivation licensing system doesn’t prevent what is known as “vertical integration” or the ability of a few big players to capture most of the market. As former Rhode Island Rep. Patrick Kennedy, a recovering drug addict and member of the Kennedy clan, has noted, “It’s a smokescreen for big business.”

That and concerns about the potential heavy taxation of cannabis is causing a number of local growers, including some in the Emerald Triangle of Mendocino, Humboldt and Trinity counties, to oppose the measure.

Finally, there are the many unknowns. Marijuana would still be illegal under federal law, meaning cannabis businesses would continue to operate on an all-cash basis — given that banks are federally regulated — increasing the risk of criminal activity. Law enforcement groups also are opposed to Proposition 64 because of the lack of a clear standard for convicting drivers believed to be under the influence of marijuana. Supporters say that tax revenue from cannabis would be used to fund research to develop something similar to the blood-alcohol test. But wouldn’t it be better to have such a standard in place before rushing to move ahead with legalization?

If we learned anything from California’s medicinal marijuana law it’s the danger of passing a poorly worded ballot measure with the intent to fix it at some later date. Let’s not repeat that mistake by approving a proposition that potentially would create more problems than it would solve.

The Press Democrat recommends a no vote on Proposition 64.