Facing an uphill battle, proponents of a ballot measure to legalize marijuana are mapping out a campaign stressing the millions of dollars in tax revenue that pot could provide.

The initiative, sponsored by Oakland marijuana magnate Richard Lee, would legitimize the sale of marijuana and allow pot shops to open their doors in cities that permit it. Local authorities could also decide how to tax and regulate marijuana sales, although it’s unclear if federal officials would tolerate such a bold and unprecedented move.

Many of the state’s most important politicians want nothing to do with the measure, which would allow anyone over the age of 21 to grow or possess a drug considered by the federal government to be highly addictive and of no medical value.

Despite lawmakers’ reluctance, political consultants working on the initiative claim a marijuana tax could contribute more than $1 billion toward reducing California’s $20 billion budget deficit. Opponents call that a pipe dream.

“As my wife says, that’s just bong economics,” said John Lovell, a lobbyist who represents a coalition of law enforcement groups that are against the measure.

In fact, there is uncertainty about how much tax revenue could be generated, or if federal officials will even allow the legalization of marijuana. According to the state Legislative Analyst’s Office, “The amount of all the various revenues that could be generated by this measure depend considerably on the extent to which the federal government enforces its laws against marijuana in California.”

Last February, US Attorney General Eric Holder said the Justice Department would no longer raid medical marijuana dispensaries that comply with state law.

However, his office has not indicated if it would tolerate marijuana for people without a medical need.

A Republican political consultant predicted the issue would find little support from politicians outside the Bay Area.

“My guess is most if not all Republicans will oppose it and some Democrats will support it,” said Ray McNally, a partner in the Sacramento consulting firm McNally Temple & Associates. “Others running for statewide office will probably hide under the bed.”

Phone calls and emails to three gubernatorial candidates – Jerry Brown, Steve Poizner and Meg Whitman – were not returned.

Four Democratic candidates for Attorney General, Kamala Harris, Chris Kelly, Ted Lieu and Alberto Torrico, said they oppose the measure. Republican Tom Harman said he opposes it. Five other GOP candidates did not return phone calls seeking comment.

The 2010 campaign is better funded and organized than previous attempts to decriminalize marijuana. Lee, founder of an Oakland medical marijuana dispensary and Oaksterdam University, a marijuana trade school, spent $1 million to gather 680,000 signatures calling for the initiative to be placed on the November ballot.

The Secretary of State’s office is now checking to see whether at least 433,971 of those signatures – the minimum required for placement – are valid.

Lee’s corporate holding company, S.K. Seymour LLC, has also hired SCN Strategies, a San Francisco political consulting firm that has worked for Los Angeles Mayor Antonio Villaraigosa and Hillary Clinton’s 2008 presidential campaign. Lee has also contracted with Blue State Digital, an agency that has provided advocacy, fundraising and social networking technology for the website TaxCannabis.org.

“This is not a whim,” Dan Newman, a consultant with SCN Strategies, said. “The initiative is carefully crafted, well-funded, and professionally run. There will be TV ads, mail, sky writing – whatever it takes to communicate with voters – and a very active and engaged new media component.”

Lovell, the lobbyist for the state Police Chiefs Association, the Narcotics Officers Association and the Peace Officers Association, said opponents saw some of the same arguments in 2008 in the battle over handling non-violent drug offenses.

“We learned a couple of things from that,” he said, “We did not have to match the legalizers dollar for dollar in the campaign. They outspent us five to one. But our message was before voters and it resonated. That’s why we succeeded.

Polls show Californians’ attitudes about pot have softened since medical marijuana dispensaries began opening in 2004. In the two decades before that, – 35 percent in 1983. By 2004, the number had crept up only slightly to 39 percent.

But the past five years have seen an enormous shift in popular sentiment. In a Field Poll conducted in April 2009, 56 percent of voters said they were in favor of legalizing marijuana for recreational use and taxing its sale.

“When something changes I ask myself what happened, what events had an impact on voter attitudes,” said Mark DiCamillo, the director of the Field Poll. “The biggest thing I can think of is Initiative 215,” he said, referring to the ballot measure that legalized marijuana for medical purposes and took effect in 2004. “It seems to have moderated and taken away some of the public fears about marijuana.

Yet analysts and pollsters agreed the latest survey reflects only moderate support.

“Fifty-six percent is a hard sell,” McNally, the Republican strategist, said. “You typically want to start out above 60 percent or above. Because as a campaign unfolds, support typically drops.

“I think this goes down. I’m not sure everyone is ready to have head shops all over the place,” he said. “That’s the other thing working against this initiative – some people have the sense that things are changing too fast. Like health care, it’s too much, too soon. In that kind of environment, do they really want to legalize marijuana?”

Steven Maviglio, the head of Forza Communications, a campaign firm in Sacramento that works with Democrats, agreed that marijuana supporters are facing an uphill battle. “They have to make it look like mainstream California to appeal to moms and swing voters, not just pot heads who want marijuana,” he said.

On the other hand, he said, voters recognize that marijuana is a multi-billion dollar crop, and it makes fiscal sense to regulate an industry that isn’t paying its fair share of taxes.

“There has been more enthusiasm for this than anything I’ve seen in a long time,” he said. I was sitting in on a focus group the other day and people are voluntarily bringing this up,” Maviglio said.