Blow in the wind: cocaine interdiction fiction.

"THERE WERE those who did not think it was possible to change the availability of cocaine in the United States," drug czar John Waiters said during a November visit to Colombia. "There's no question that's happened."

But according to a report from the Government Accountability Office (GAO) published that same month, there's no shortage of cocaine, or of questions about the impact of interdiction. The report used the word "problematic" n times to describe the evidence on which the government relies to measure its success.

To begin with, the government does not know how much cocaine moves from Latin America to the U.S. each year. The estimate for 2004, the GAO noted, was "between 325 and 675 metric tons," but "such a wide range is not useful for assessing transit zone interdiction efforts."

Waiters' Office of National Drug Control Policy (ONDCP) bragged that cocaine production was cut by nearly a third between 2001 and 2004, while "seizures and disruptions" increased by more than 40 percent, reaching almost 200 tons. "Despite these reported successes in disrupting cocaine trafficking," the GAO noted, a 2004 RAND Corporation study "indicates that the retail price of cocaine in the United States continued to decline through the second quarter of 2003 ... while retail purity remained relatively high, indicating that the supply of cocaine had not been reduced."

More to the point, the dramatic increase in interdiction has not had a noticeable impact on cocaine use. In the National Survey on Drug Use and Health, the number of past-month cocaine users was almost exactly the same in 2004 as it was in 2002 (around 2 million). During the same period, past-month cocaine use among high school students, as measured by the Monitoring the Future study, likewise remained essentially flat.

The report also observes that there are no good nationwide data on drug use among populations not covered by such surveys--a significant problem, since "a large portion of major cocaine (and other drug) users are members of generally hard-to-survey populations, such as the homeless or incarcerated." The fact that drug use is common in prisons not only makes it hard to measure the impact of interdiction; it also makes you wonder how people like Waiters can believe that preventing drugs from entering the country is a practical mission to begin with.