In the Western world today, there is a group of people who live in a haze of unreality, and are prone at any moment to break into paranoia, hallucinations, and screaming. If you try to get between them and their addiction, they will become angry and aggressive and lash out. They need our help. I am talking, of course, about the Drug Prohibitionists: the gaggle of politicians, bishops and journalists who still insist that the only way to deal with the very widespread drug use in our societies is for it to be criminalized, where it is untaxed, unregulated, controlled by armed criminal gangs, and horribly adulterated.

An addict can only really begin to grapple with his problem when he hits rock bottom. This year, the prohibitionists hit theirs, as they unleashed the destruction of Mexico. But in Britain, there was a smaller story that serves as a perfect parable for how fact-free their cause now is.

In March, two young men named Louis Wainwright and Nicholas Smith died in a nightclub in the English seaside town of Scunthorpe. We now know what happened: they drank massive amounts of alcohol along with sedatives. But the prohibitionists embarked on a sudden, violent hallucination. They immediately announced -- with no evidence, long before the autopsy -- that these young men were the first victims of the party drug Mephedrone. The Drug Warriors had been nervously eying this a snort-or-swallow amphetamine since it started growing in popularity in 2008, and had swelled to be as popular as ecstasy. Surely it was evil! Surely it would kill! Now, they said, it had -- and it must be banned.

From the moment the story broke, it became filled with fictions and fantasies. Even the name of the drug was a fake. Somebody had randomly entered into Wikipedia two days before the deaths that the drug was called 'Meow-Meow'. Nobody I have ever met called it that. The term doesn't appear in online discussions of it anywhere. But the Sun slapped it on the front page, and the rest of the media followed. Me-ow. The drug had been used by millions of people across the world with no recorded fatalities at that point, but here's a selection of headlines from the conservative newspaper Daily Mail alone: "They're playing Russian Roulette with their lives!" "The Death Drug." "Legal But Lethal." "It triggers fits, psychosis, and death." Illustrated with pictures of Wainwright and Smith, even though the autopsies have proven they never touched the drug.

On the back of this drug-induced hysteria, the government announced it would ditch the rest of its pre-election parliamentary program and immediately criminalize Mephedrone. They were enthusiastically backed by the Conservatives and Liberal Democrats. Only a few brave politicians, like the Lib Dem Dr Evan Harris and the UK Independence Party's Nigel Farage, politely asked for evidence, and were rudely shouted down. Don't you know! Children are DYING! When it was proven that Mephedrone was framed, and had become the Birmingham Six of drugs, no politician apologized. Nobody suggested repealing the ban. Everybody has carried on straight-faced. It is the surest sign of a harmful addiction when you can't even acknowledge what you did the night before.

To be fair, though, one group of people has hugely benefited from the ban, and have every reason to be grateful. They are Britain's armed criminal gangs. Until this spasm, Mephedrone was sold by bespectacled chemists, who manufactured a clinically pure product, and had recourse to the law if their property rights were infringed. Not now. The trade has been transferred to the Mafia. Their product is regulated by nobody and so filled with deadly filth. The right to sell it on a particular patch will be established by shoot-outs, in which innocent people are often caught up by accident.

The ban on mepehedrone is a perfect parable about the prohibitionists' habits of mind. They waved fictitious victims under a fictitious name and said they were fighting for sobriety. In truth, they have been trying to suppress any sober discussion of risk for years. In 2009, Professor David Nutt, the chairman of the British government's scientific advisory panel on drugs, pointed out a simple fact: taking ecstasy is about as dangerous as horse-riding, which kills 10 people a year there, and causes 100 traffic accidents. Everybody who checked agreed the facts were true. He was immediately fired. Since then, seven other members of the panel have resigned, because the government can't handle the truth. The best evidence we have suggests taking Mephedrone is less dangerous than eating peanuts, an activity that also kills ten people a year. Should we send the police in to bust anybody spotted with a handful of dry roasted?

But prohibition is not about really reducing danger. If it was, we would start with by far the two deadliest drugs in the world: alcohol, which kills 40,000 a year, and tobacco, who kills 80,000. If the law is about "sending a signal" that it is a "bad idea" to kids to risk your health with a drug, surely we need to immediately prohibit them? Yet virtually everyone is grown up enough to know that a ban on them wouldn't stop people using. In the US in the 1920s, banning alcohol simply created a vicious criminal class selling a vastly more deadly product, and deprived the government of any tax revenue on it. The ban became more harmful than the drug itself. Why do we think it is any different with cannabis, or ecstasy, or cocaine?

The prohibitionists sometimes say that if alcohol was invented now, they would want to ban it, before its use became widespread. But the use of prohibited drugs is already buttered thickly across British society: some 34 percent of us have used an illegal drug, including our Prime Minister, Deputy Prime Minister, and the last three visiting Presidents of the United States. We can't even stop drugs from being freely available in prison, and we have the inmates there under armed guard.

There is a way out of this, and a new reason to do it urgently. In the early 1930s, the US ended alcohol prohibition partly because it had mid-wifed the criminal career of Al Capone and a thousand other goons, but primarily because they needed the taxes as the Depression struck. This November, California is having a referendum on whether to legalize cannabis and slap an alcohol-sized tax on it. At the moment, the legalizers are ahead in the polls. People are being persuaded the evidence from a 2005 study by Harvard University economist Professor Jeffrey Miron, showing that legalization would raise $7bn a year in taxes, and saved $13bn on wasted police, court, and prison time. The stoners, it turns out, will save us from ruin.

Perhaps the most startling international comparison, though, comes from Portugal. They decriminalized person possession of all drugs in 2001, and the prohibitionists screamed that children would soon be rolling in the gutters with needles jutting out of every available vein. What really happened? A detailed study by the Cato Institute has found that drug use has stayed the same, and slightly fallen among young people. Now, they treat addicts as ill people who need help, not criminals who should be banged up.

I know it will be hard for the prohibitionists to kick their habit. We will all need to support them as they finally leave behind their hallucinogens. I am happy to set up Prohibitionists' Anonymous, where they can confess the fears that have led them to this dark place. But the Mepehedrone madness was the equivalent of stealing your mother's jewelry and selling it for your next fix. Drug Warriors, it's time to sober up.

This article appeared as Johann's monthly column for GQ magazine in Britain. If you'd like to read these columns a month early, subscribe to GQ here.

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