Is the Prohibition of 'Pot' coming to an end in the US? The scene in Seattle is not what it seems at first glance. The market is only possible because, officially speaking, the stallholders and their customers are not potheads, but "patients"" certified under local laws to use medical marijuana. To enter, everyone must show their "green card"" authorisations and sign a declaration promising not to resell on the street. Officially, the market is not a market, but a "meeting point" for licensed marijuana growing collectives, and an "access point" for the patients to get their "medicine" in return for a "donation." A heavily air-conditioned room is available for patients to "medicate" themselves for conditions that range from terminal cancer to a mildly arthritic neck. That may all change after November 6 - general election day - when voters in Washington state will decide not just on whether to give Barack Obama a second term, but also whether to legalise marijuana for recreational use. If the referendum - known as Initiative 502 - is passed by a simple majority, everyone over the age of 21 in the state would, in theory, be able to go to a government-run shop and buy up to 1oz of marijuana or equivalent in edible products without fear of being arrested or harassed. The initiative is just one example of the momentum to legalise marijuana. This week, Andrew Cuomo, the governor of New York, suggested that young people caught with small amounts of marijuana should not be arrested, further decriminalising the drug. Like Washington, Colorado will also vote in November on a similar motion to fully legalise, while a Rasmussen Reports poll last month found that 56 per cent of Americans now support legalising and taxing marijuana like alcohol. Early polls show similar support (55 per cent) for initiative 502 in Washington state. There is now a distinct possibility that, for the first time, a US state will vote to legalise. Although there have been previous state-level initiatives to legalise pot - most recently in 2010 when California's Proposition 19 which failed to win a majority - none has had the kind of establishment backing gathered by the Washington campaign, which is supported by former US attorneys, an FBI supervisor and several judges and public health specialists. Initiative 502 is different because it has been designed to disarm critics, according to Alison Holcomb, the campaign director who is also a longtime criminal defence lawyer in the state. "We wanted to put a proposal in front of voters that addressed their concerns," she said at the group's modest offices in Seattle where the $5m autumn publicity campaign is being coordinated, "which on marijuana are fears over drug-driving and protecting kids." To allay concerns, the bill bans marijuana shop-window displays or advertising and insists all marijuana will be produced in-state, under government licence, with growers, refiners and retailers all taxed at 25 per cent. There will also be a strict provision outlawing "drug-driving"" just like drink-driving. There remains, however, one major problem: even if 502 passes, marijuana will still be an illegal drug under federal law. A yes vote in Washington state or Arizona will therefore create a showdown between state and federal governments. John McKay, a former US attorney for Washington state who is backing the initiative, says the showdown is reminiscent of the state-level rebellion that led to the end of Prohibition. "I think the states are going to have to rebel again before the federal government changes its policy," he said. States are going to have to say that the policy on marijuana - which creates a black market where only the bad guys profit and criminalises millions of ordinary people - has failed. Support for marijuana legalisation comes from different directions. For some, the arguments are economic - Washington state's government audit office estimates legalisation will generate some $516m a year in much-needed tax revenues. For others, legalising is the only practical response to the failure of the US's 40-year, $1 trillion "war on drugs" to stop the flow of narcotics. Decriminalising pot, they say, would relieve pressure on overpopulated prisons and free the hands of police who make more than 850,000 marijuana-related arrests every year - that's one every 37 seconds. For a fourth group marijuana is genuinely medicinal, like the New York supreme court judge who wrote movingly this month in the New York Times about how, after taking cocktails of pharmaceutical drugs, marijuana was the only drug that gave him an appetite when fighting the nausea brought on by his chemotherapy and allowed him to sleep peacefully. Ironically, one place support for 502 will not be forthcoming is among the stallholders at that Seattle cannabis farmers" market, who fear the strict rules would eat into their profits (donations), make their "medicine"" too expensive and precipitate a wave of drug-driving convictions. "We don't want it," says Dedrick, whose cinnamon buns are flying off the table like the hot cakes they are. If they license growing, it will drive it away from those who put love into our medicine. The opposition among the medical marijuana community, while strong, is not universal. Across town from the market, at the Green Buddha dispensary, the sentiment is different. Muraco, the owner, says she'll embrace 502 even if it means she'll go out of business. It's what we've been fighting for all these years, isn't it? If it happens, five other states will follow in five years, you watch. Legalisation, she says, is a natural, inevitable progression. When Washington state legalised medical marijuana in 1998 "green cards"" were extremely tightly controlled, and Muraco, who suffered from seizures, was one of the very first to receive one. But since "naturopathic"" doctors were allowed to authorise the use of marijuana, "any dude with a bad foot" can now get a note from his doctor, she admits. As a result, the number of dispensaries, from a handful two years ago, have exploded to more than 200 in Washington state. Certified medical marijuana users are reported to have hit 35,000, with one dispensary owner saying "hundreds" were joining the list every day. Legalisation would, in many ways, be a recognition of existing realities. Supporters of legalisation say the polls reflect a change in US public opinion. Even those who disapprove of drugs increasingly appear to feel that criminalising marijuana is out of step with an America in which surveys show that 16.7 million citizens used marijuana in the past month, and perhaps as many as 100 million will have smoked at some point in their lives. Support is not just confined to the liberal Left. Last March, to the anger of anti-drugs groups, Pat Robertson, a deeply conservative Christian televangelist, came out in favour of legalisation, citing the "social cost"" of continuing to criminalise marijuana. Gary Johnson, the two-term Republican governor of New Mexico and 2012 presidential candidate for the Libertarian Party, is also a proponent and will make liberalisation part of his platform during the election, in contrast to both Barack Obama (who has admitted to smoking pot in his youth) and Mitt Romney, who both remain opposed. "We are at a tipping point and we're going to legalise marijuana sooner or later," Johnson said in a telephone interview. We need to understand that the problems associated with marijuana are caused by prohibition itself. That is what is tearing people and families apart and turning otherwise taxpaying citizens into criminals. If 502 passes no one knows how the federal government will react to such a naked affront to its authority. The early signs are that it will fight the rebellious states. In what many take to be a signal of intent, federal agencies have recently mounted raids on "legal"" marijuana dispensaries in some of the 14 states that have passed medical marijuana laws. California, Washington and Arizona have been the focus of raids, which the Department of Justice says are targeted only at people using the medical marijuana laws (which the Department has officially tolerated since 2009) as a cover for large-scale cannabis growing and dealing. John Mckay, who was once the chief federal prosecutor for drug crimes in Washington state, feels it is almost certain that the federal government will try to assert its authority through the courts. In the short term, this will put legalisation on ice, but as happened with Prohibition, he believes it will start an argument that history suggests will almost certainly - eventually - lead to legalisation. "There is no doubt that 502 sets up a major showdown," he said. I bet the federal government already has its case prepared, but, at last, both sides will get to make the argument in the open. For supporters of legalisation, that can only be a good thing.