Emilio San Pedro
The Bulldog Cafe is allowed to sell marijuana for medicinal purposes
In 1996, voters in California approved a referendum that made it legal for the first time in decades in the US for people to consume cannabis for medicinal purposes.
More than a dozen states have followed suit since and several others - the most recent of which is Massachusetts - have approved laws decriminalising the possession of small amounts of the drug.
Now, there are moves afoot in California to go further to fully legalise marijuana.
Evidence of the impact that the approval of medicinal marijuana has had on some areas of California is clear in Oakland.
Across the bay from San Francisco, it has come to be known as Oaksterdam, in a nod to the symbolic global capital of marijuana deregulation, Amsterdam.
The relaxed approach to marijuana use in this part of Oakland has led to the opening of several marijuana dispensaries.
They are establishments in this once deprived area of town which sell a broad array of cannabis related products, from food products such as brownies and cereal bars laced with cannabis to traditional marijuana for smoking.
"This is where it all started," says Richard Lee, a leading advocate of the legalisation of cannabis, pointing to a building where the first ever dispensary was opened in 1996.
His sense of excitement is palpable as he shows me around Oaksterdam, which is also home to a facility where state residents can get the ID needed to establish their right to use cannabis for medical purposes.
Richard Lee runs Oaksterdam University which opened in 2007
The area is also home to the Oaksterdam University, which Mr Lee runs.
He shows me around the student union of the university, which he describes as a trade school for all of those interested in finding a place in the thriving cannabis trade that medicinal marijuana has spawned.
Mr Lee tells me that making cannabis use legal would make economic sense but would also help in the fight against the Mexican drugs cartels.
"According to some estimates, the Mexican cartels get 60-70% of their money - their profit - from cannabis," he tells me.
"So if we cut that out of the equation then theoretically 60-70% of the violence they perpetrate would be cut out, because they'd have less money for the guns and weapons and ammunition to kill people and to spend on bribing officials and all the rest," Mr Lee says.
That perspective, along with the fact that California state authorities estimate marijuana could bring in nearly $1.5bn a year in much needed tax revenue if it were legalised, has led to increased support among the state's voters for the full legalisation of the drug.
Politicians like Tom Ammiano, who represents one of the most liberal districts of San Francisco in the California state assembly, have been paying close attention.
Mr Ammiano came into politics as a trailblazing gay rights activist in the 1970s and has long advocated greater tolerance of cannabis use.
Earlier this year, he took that approach one step further and introduced a bill in the California state assembly which, if approved, would grant cannabis the same legal status in the state as alcohol and tobacco.
That would put California ahead of even Amsterdam, where marijuana use is tolerated but not altogether legal.
Sitting with him in his office in the state government building in San Francisco, with its sweeping views of the city, it becomes clear that his proposal is far from a flight of fancy.
He tells me he has been finding that more and more of his colleagues in the state assembly are coming around to seeing why moving towards legalisation makes perfect sense.
"People across the board, whether they're conservative or liberal, have come to realise that the so-called war on drugs has failed and failed miserably," Mr Ammiano says.
"In fact, it's costing us money instead of saving us money. This new approach would be a way for the policing efforts to be focused on the big bad guys, the cartels, with their violence and murder, and lighten up on the more minor offences. We like to say prohibition is chaos and regulation is control," he adds.
"On the streets, a drug dealer does not ask a kid for his ID before selling him cannabis," he concludes with an acerbic, humorous tone that serves as proof that he has, beyond politics, also had some success in his other career as a stand-up comedian.
But, despite his optimistic tone, Mr Ammiano says he knows that those who oppose his proposal, including key figures in the medical and law enforcement community, are armed with statistics pointing to the damaging long-term effects of the drug and have the stamina and resources to wage a major fight to ensure that the bill never gets signed into law.
One of those opponents is Ronald Brooks, president of the National Narcotic Officers' Associations' Coalition, which represents more than 70,000 narcotics enforcement officers in the US.
We meet in the town of Redwood City, south of San Francisco and, as I get in his car, we drive past what appears to be a nondescript office building.
However, he tells me that in the 1980s it was a bank - the place where his partner on the police force was killed in front of him by a ruthless marijuana dealer, who was carrying out a bank robbery to fund his drug business.
He says experiences like that have strengthened his resolve that America can't allow itself to take a more lenient approach to marijuana.
"This argument of freeing up law enforcement so that we can take on the cartels is seriously flawed," he tells me.
Ronald Brooks is firmly against the proposed change in the law
"This is really a hoax being perpetrated on the voters of California to authorise their political agenda - that is to legalise marijuana as one step to legalise drugs in America because they simply don't think the government ought to control drugs," he adds.
"The people who are going to lose if this gets approved are the taxpayers, because we're going to have increased costs associated with this, both healthcare and law enforcement costs, and the people who have to drive on the state's highways who are going to be in danger from being hit by someone intoxicated from using cannabis. This is simply a reckless public policy," he concludes.
Back across the San Francisco Bay in Oakland, specifically Oaksterdam, the patrons of the Bulldog Cafe are enjoying their legally sanctioned right to consume marijuana for medicinal purposes.
Gary has travelled from Texas for the weekend to attend a seminar on the cannabis trade at the Oaksterdam University across the street.
He is in his 50s, but says he is hoping to take the information he has picked up in his course on the cannabis business and make a life-transforming move in the coming months to California.
"My girlfriend and I are interested in moving to California from Texas to become a part of this here. We're not quite sure where we fit in but we want to get into the business itself. We feel it's an emerging industry, and this is where I feel compelled to come," he tells me as the smell of cannabis wafts through the room.
Like Gary, there are hundreds of others participating in the courses at the Oaksterdam University on any given week.
Beyond that, there are more than 200,000 people in the state registered as consumers of marijuana for medicinal purposes.
As for Mr Ammiano's proposal to legalise marijuana in the state, that is still making its way through the California state assembly and it is difficult to say whether it will succeed or not.
What is clear, however, is that whatever the outcome of the legalisation proposal, the medical marijuana law and the multi-million dollar industry it has spawned appear to be here to stay in California.