With the global economy collapsing all around us, the last issue President Barack Obama wants to talk about is the ongoing War on Drugs. But if he doesn't - and fast - he may well have two collapsed and haemorrhaging countries on his hands. The first lies in the distant mountains of Afghanistan. The second is right next door, on the other side of the Rio Grande.
Here's a starter for 10 about where this war has led us. Where in the world are you most likely to be beheaded? Where are the severed craniums of police officers being found week after week in the streets, pinned to bloody notes that tell their colleagues, "this is so that you learn respect"? Where are hand grenades being tossed into crowds to intimidate the public into shutting up? Which country was just named by the US Joint Chiefs of Staff as the most likely after Pakistan to suffer a "rapid and sudden collapse"?
Most of us would guess Iraq. The answer is Mexico. The death toll in Tijuana today is higher than in Baghdad. The story of how this came to happen is the story of this war - and why it will have to end, soon.
When you criminalise a drug for which there is a large market, it doesn't disappear. The trade is simply transferred from chemists and doctors to gangs. In order to protect their patch and their supply routes, these gangs tool up - and kill anyone who gets in their way. You can see this any day on the streets of London or Los Angeles, where teen gangs stab or shoot each other for control of the 3,000 per cent profit margins on offer. Now imagine this process on a countrywide scale, and you have Mexico and Afghanistan today.
Drugs syndicates control 8 per cent of global GDP - which means they have greater resources than many national armies. They own helicopters and submarines and they can afford to spread the woodworm of corruption through poor countries right to the top.
Why Mexico? Why now? In the past decade, the US has spent a fortune spraying carcinogenic chemicals over Colombia's coca-growing areas, so the drug trade has simply shifted to Mexico. It's known as the "balloon effect": press down in one place, and the air rushes to another.
When I was last there in 2006, I saw the drug violence taking off and warned that the murder rate was going to rocket - but I didn't imagine it would reach this scale. In 2007, more than 2,000 people were killed. In 2008, it was more than 5,400 people. The victims range from a pregnant woman washing her car, to a four-year-old child, to a family in the "wrong" house watching television. Today, 70 per cent of Mexicans say they are frightened to go out because of the cartels.
The cartels offer Mexican police and politicians a choice: plato o plomo. Silver or lead. Take a bribe, or take a bullet. Juan Camilo Mourino, the Interior Secretary, admits the cartels have so corrupted the police they can't guarantee the safety of the public any more. So the US is trying to militarise the attack on the cartels in Mexico, offering tanks, helicopters and hard cash.
The same process has happened in Afghanistan. After the toppling of the Taliban, the country's bitterly poor farmers turned to the only cash crop that earns them enough to keep their kids alive: opium. It now makes up 50 per cent of the country's GDP. The drug cartels have a bigger budget than the elected government, so they have left the young parliament, police force and army riddled with corruption and virtually useless. The US reacted by declaring "war on opium".
The German magazine Der Spiegel revealed that the NATO commander has ordered his troops to "kill all opium dealers". Seeing their main crop destroyed and their families killed, many have turned back to the Taliban in rage.
What is the alternative? Terry Nelson was one of America's leading federal agents tackling drug cartels for over 30 years. He discovered the hard way that the current tactics are useless. "Busting top traffickers doesn't work, since others just do battle to replace them," he explains. But there is another way: "Legalising and regulating drugs will stop drug market violence by putting major cartels out of business. It's the one sure-fire way to bankrupt them, but when will our leaders talk about it?"
Of course, the day after legalisation, a majority of gangsters will not suddenly join the Hare Krishnas and open organic food shops. But their profit margins will collapse as their customers go to off-licences and chemists, so the incentives for staying in crime will largely end. We don't have to speculate about this. When alcohol was legalised, the murder-rate fell off a cliff - and continued to drop for the next 10 years. (Rates of alcoholism, revealingly, remained the same.) No, Obama doesn't want to spend his political capital on this. He is the third consecutive US President to have used drugs in his youth, but he knows this is a difficult issue, where he could be tarred by his opponents as "soft on crime".
Yet remember: opinions are febrile in a depression. At the birth of the last great downturn, support for alcohol prohibition was high; within five years, it was gone. The Harvard economist Professor Jeffrey Miron has calculated that drug prohibition costs the US government $44.1bn per year - and legalisation would raise another $32.7bn on top of that in taxes if drugs were taxed like alcohol. (All this money would, in a sane world, be shifted to drug treatment.)
Can the US afford to force this failing policy on the world - especially when it guarantees the collapse both of the country they are occupying and their own neighbour?
Drug addiction is always a tragedy for the addict - but drug prohibition spreads the tragedy across the globe. We still have a chance to take drugs back into the legal regulated economy, before it's too late for Mexico and Afghanistan and graveyards-full of more stabbed kids on the streets of Britain. Obama - and the rest of us - have to choose: controlled regulation or violent prohibition? Healthcare or warfare?