Several Latin American and European countries pressed their case to decriminalize drugs at a special session of the United Nations this week. They came up short. The document that emerged maintained a basic prohibitionist stance. But the advocates for a softer touch did garner some prominent backers, including former U.N. Secretary General Kofi Annan, who argued in an op-ed that the war on drugs has failed .

"Prohibition has had little impact on the supply of or demand for drugs," Annan wrote. "When law enforcement succeeds in one area, drug production simply moves to another region or country, drug trafficking moves to another route and drug users switch to a different drug. Nor has prohibition significantly reduced use. Studies have consistently failed to establish the existence of a link between the harshness of a country’s drug laws and its levels of drug use."

Measuring the effectiveness of prohibitions can be tricky. For this fact-check, we're looking into the connection between getting tough on drugs and less use.

We reached out to the Kofi Annan Foundation and did not hear back, so we don’t know what specific studies he had in mind. We reached out to several experts in the field and generally, they agreed with his statement.

Jonathan Caulkins, professor of public policy at Carnegie Mellon University, has worked on some of the broadest examinations of drugs in America. Caulkins was part of the team that wrote the U.S. Office of National Drug Policy’s latest assessment of how much users spend on drugs .

"There is some research that finds increased harshness reduces use, but the overall statement is true," Caulkins told PolitiFact. "By and large, expanding toughness beyond a basic prohibition plus the usual amount of enforcement does not drive down use."

European countries created a natural laboratory of sorts on the interplay of marijuana laws and marijuana use. Over the decades, different countries have adopted a variety of approaches. The European Monitoring Centre for Drugs and Drug Addiction examined the results in each place .

The center’s legal analyst Brendan Hughes told us no clear relationship emerged.

The following chart shows why. In Italy, for example, penalties went up but so did use. Denmark also tightened its laws and saw almost no change. On the flip side, the United Kingdom adopted lighter sanctions and the prevalence of marijuana fell. But when Slovakia did the same, usage rose.

One approach to gauging the impact of enforcement is to track trends in the price of drugs, after factoring in changes in purity. Based on the basic rules of supply and demand, if the price falls, use is expected to rise, and vice versa.

The most recent analysis from the U.S. Office of National Drug Policy dates back to 2008. While the numbers could have changed since then, that report had discouraging news for the zero-tolerance camp. The price of heroin had fallen about 30 percent for all grades or purity in 10 years, cocaine showed a modest but steady decline, and some grades of marijuana saw a 50 percent drop in price. (This predates by many years the decriminalization moves in Colorado and Washington State.)

Thomas Kerr, Co-Director of the Urban Health Research Initiative at the British Columbia Centre for Excellence in HIV/AIDS, said the federal data provide "compelling evidence" of the limits of a get-tough policy.

"As expenditures on drug control increased dramatically, use has not gone down, nor has price, while purity has gone up," Kerr said.

Kerr pointed to research in Thailand, where simple possession of heroin can lead to up to 10 years in prison, that found harsh enforcement tactics had no apparent impact on heroin users.

We did find one study that concluded that greater incarceration reduced drug use. Economist Steven Levitt at the University of Chicago co-authored a 2001 article that examined cocaine patterns between 1980 and 2000. It was a time, Levitt wrote, when the number of prisoners jailed for drug-related offenses rose 15-fold.

"We estimate that cocaine prices are 10 to 15 percent higher today as a consequence of increases in drug punishment since 1985," Levitt wrote. "Based on previous estimates of the price elasticity of demand for cocaine, this implies a reduction in cocaine consumed of as much as 20 percent."

However, that conclusion hangs on a rising price of cocaine, and data gathered after that report showed prices falling, not rising. That doesn’t mean that cocaine use rose in response. As a sign of the complicated nature of drug consumption, federal data showed that from 2002 to 2010, the amount of cocaine used in the United States fell by half.

An article by Caulkins and his colleague Peter Reuter at the RAND Corporation, a prominent think tank, concluded that enforcement can sometimes help stop a mass market from forming, such as in the case of a new drug coming on the scene. But once a drug takes hold , "there may be little return to intense enforcement. A modest level of enforcement may generate most of the benefits from prohibition."

Caulkins emphasized that the policy choice is not between a total ban and no ban at all.

"If one goes from the basic enforcement necessary to make a prohibition real to no prohibition at all, then use and abuse would go way up," he warned.

Our ruling

Annan said that studies consistently fail to find a link between the harshness of a country’s drug laws and its levels of drug use. The experts we reached and the data and reports we found largely backed that up. In some places, tougher penalties led to less use. In others, tougher laws had no effect at all.

In the United States, while there are shifting patterns of drug use, there is no simple relationship to the severity of the nation’s drug laws.

The caveat is that from the European study, relaxing penalties had equally unpredictable results.

Annan’s statement needs that bit of context. We rate this claim Mostly True.

https://www.sharethefacts.co/share/57b76f03-26f4-41a0-8a93-f3bfa84ccb0f