Lt. Gov. Gavin Newsom is a deft politician. So when he announced that he would lead the latest campaign to legalize marijuana in California, the movement gained an instant level of legitimacy.

Newsom calls the war on drugs an abject failure and believes most politicians share his view, though they "say one thing publicly and another thing privately."

"If it was good politics, you'd have a lot more politicians out front," Newsom told me last week. "I can't defend the status quo. I feel an obligation to make a better argument."

Marijuana has been all but legal in California since 1996, when voters approved it for medical use. That has turned into a mess, with some growers denuding hillsides and using chemicals on what they claim is medicine, while bottom-feeding physicians blithely sell scripts, mostly to young men who claim one ailment or another.

(AP Photo/Brennan Linsley)
(AP Photo/Brennan Linsley)

Newsom believes California can do better by legalizing the weed, and licensing, regulating and taxing growers, distributors and retailers. Details to come.

His immediate allies include the ACLU and academics, with likely funding for any initiative from billionaire legalization advocates George Soros and Peter Lewis, the chairman of Progressive Auto Insurance.

In the initial announcement, the ACLU said Newsom would lead a "blue ribbon panel" of experts who would spend 18 to 24 months studying how Colorado and Washington implement marijuana legalization, and learn from those states' experiences.

The Oct. 17 press release promised policy "white papers," "round-table discussions" and "town hall events," presumably leading to a 2016 ballot measure. That still may happen. But Newsom told me the measure could be on the ballot in November 2014.

The reason has little to do with policy and much to do with politics. New polls including one by Gallup last week showing attitudes are shifting fast in favor of legalization. In September, a Public Policy Institute of California poll said 60 percent of likely voters back legalization, though Latinos oppose it by a wide margin, as do Republicans.

Newsom, who plans to seek re-election as lieutenant governor in 2014 and likely will run for governor in 2018, is taking a risk. If pot becomes legal and the regulation becomes problematic, he'd be tarred as the politician who led the effort.

There's also an incongruity between Newsom's causes and his new role in the legalization effort. As lieutenant governor, he has championed economic development and higher education. As San Francisco mayor, he combated homelessness.

Expanded availability of marijuana hardly would make for greater worker productivity. While his stand might play well on college campuses, weed never mixes well with serious academic studies. Homeless people definitely don't need drugs to be more readily accessible.

The reductionist explanation is that Newsom is seeking the next big issue, after having led politicians by marrying same-sex couples at City Hall a decade ago when he became mayor of San Francisco.

The issues are not equivalent. Marriage equality is a matter of civil rights. Marijuana raises no equal-protection question. It is, instead, a matter of commerce, taxation and self-gratification.

I was part of the majority of California voters who voted down the legalization initiative, Proposition 19 of 2010, by a 53.5 to 46.5 percent margin. With or without legalization, marijuana is readily available, as it was in my hazy high school days decades ago. But there's a serious public health issue, one that advocates, including Newsom, gloss over.

"Any cannabis use before age 14 is a risk factor for developing a psychotic illness," said UC Davis Medical School Professor Cameron Carter, a psychiatrist who focuses on young people who are severely mentally ill. "For people who have schizophrenia, marijuana can cause more symptoms."

Newsom says marijuana is less harmful than alcohol. That may be true for some people. But just as chronic alcoholics can buy Thunderbird at corner stores in the Tenderloin, schizophrenics could buy legalized marijuana at whatever retail outlet would sell it.

"You can't bring to widespread availability another mind-altering substance without social consequences," said Sacramento lobbyist John Lovell, who represents the California Police Chiefs Association, which has opposed legalization.

Whether the campaign is in 2014 or 2016, Newsom believes winning would be the easy part. Grappling with policy issues will be tougher. He posed some questions. I had others.

"How can we administer it in a safe way and make sure it is kept out of the hands of kids, that there is transparency, and that people don't drive under the influence?" he asked.

Would its use be legal in public places, in backyards and in shared space in apartments? What would be the legal age? Newsom thinks the age ought to be 21; others may push for 18.

What's the appropriate tax rate? Would tax revenue flow to the state general fund or be earmarked for drug treatment, research, or, the worst idea, for schools. Please spare us from another cynical And-the-kids-win-too pitch.

Would cities and counties be able to opt out of allowing marijuana retailers to operate in their jurisdictions? That would be reasonable, given how localities retain the right to ban plastic bags and regulate tobacco use more strictly than the state.

Newsom cloaks his arguments in lofty talk of criminal justice reform. But California long ago decriminalized possession. Prisons are not crowded because marijuana use is an infraction.

Newsom suggested there is a First Amendment right to advertise. If so, the state probably could not stop marijuana dealers from aiming pitches at teenagers, subtly and directly, just as alcohol and cigarette companies long have done, despite their claims to the contrary.

As any parent should, Newsom frets about how to prevent his young children from smoking weed when they become teenagers. I found value in being able to tell my kids that marijuana is illegal, along with saying this conversation was about them, not me. Even though it would be illegal for kids to buy marijuana, they'd see it's legal for adults and assume it's OK.

Then there's the matter of campaign donations. Indian tribes have become dominant political players since their casinos became legal in 2000. Nothing would stop rich and newly legitimate marijuana dealers from spreading their green in the Capitol, influencing policy and shaping regulation to their liking.

Newsom said he opposes legalizing heroin, meth and other drugs, though plenty of people support total legalization. Where to draw the line?

Legalization may be inevitable. But there should be no rush to place an initiative measure on the 2014 ballot. Newsom should take the time to learn from Washington and Colorado's mistakes. There will be many.