"The farmers are not our enemy," the State Department's Richard Holbrooke recently declared, referring to Afghans who grow opium poppies. Since the U.S. government is officially determined to wipe out their livelihood, they could be forgiven for misunderstanding. To reassure those who interpret ripping up their crops as a hostile act, Holbrooke said, "we're going to phase out eradication."

This policy shift is a long overdue admission that anti-drug efforts in Afghanistan are strengthening the Taliban insurgency and undermining stability. But the reasons Holbrooke cited for the change apply more broadly than he is willing to acknowledge, indicting not just poppy pulling in Afghanistan but an international drug control regime that has been an expensive flop for nearly a century.

Holbrooke, the special U.S. envoy to Pakistan and Afghanistan, told The Associated Press: "Eradication is a waste of money. It might destroy some acreage, but it didn't reduce the amount of money the Taliban got by $1. It just helped the Taliban." By encouraging farmers to view the theocratic insurgents as defenders against foreign invaders bent on eliminating their income, he said, "the U.S. policy was driving people into the hands of the Taliban."

Although Afghanistan's counternarcotics minister responded to Holbrooke's remarks by insisting that "our strategy's perfect," he may be the only person outside the Taliban who thinks so. Last year, according to the U.N. Office on Drugs and Crime (UNODC), Afghanistan produced 40 times as much opium as it did in 2001, the year of the U.S. invasion. It supplied 93 percent of the world's illicit opium, the export value of which was equivalent to one-third of the country's gross domestic product.

A new UNODC report shows the failure of international drug control is not limited to Afghanistan. Between 1998 and 2007 -- the U.N. Decade Against Drug Abuse -- estimated illegal production of opium more than doubled worldwide. The average U.S. retail price for a gram of heroin, adjusted for purity and inflation, fell from $597 to $364.

Estimated production of cocaine in Latin America rose from 825 metric tons in 1998 to 994 in 2007, while the inflation-adjusted price for a pure gram fell from $189 to $162 in the United States. Although comparable data are not available for marijuana, for years American drug warriors have been advertising their own failure in this area by warning that cannabis potency is rising.

As the UNODC notes, "the production costs of drugs comprise only a tiny fraction of their retail cost" (a fact "entirely attributable to their illegality"). That's one reason source control is futile: It does not have a noticeable impact on the street price of drugs, which acquire most of their value after arriving in destination countries. But if Holbrooke is right that crop eradication is a counterproductive "waste of money" in Afghanistan, how can it be a good idea in Colombia, Peru or Bolivia?

Focusing on traffickers, which is what the United States now plans to do in Afghanistan, is no more effective at reducing access to drugs than focusing on farmers. "Traffickers have proven to be resilient and innovative," the UNODC notes. Consequently, it says, "law enforcement has not succeeded in stopping the flow of drugs," and the most that can be expected is to shift the traffic from one route to another.

Meanwhile, the UNODC concedes, prohibition breeds "violence and corruption" while delivering "obscene profits" not only to the Taliban but to rebels, terrorists and thugs throughout the world, from Helmand province to Ciudad Juarez. The report notes that the attempt to prevent people from using politically incorrect intoxicants has "enriched dangerous criminals, who kill and bribe their way from the countries where drugs are produced to the countries where drugs are consumed."

UNODC Executive Director Antonio Maria Costa has a solution, however. "It is no longer sufficient to say: no to drugs," he writes. "We have to state an equally vehement: no to crime." Why didn't anyone think of that before?