Data: High Risk

In 2006, according to FBI data released in September, more people were arrested on marijuana charges in the United States than ever before: almost 830,000, up from the previous record of about 787,000 in 2005. Those arrests represented more than two-fifths of all drug arrests, and the vast majority involved simple possession, as opposed to sale or manufacture. Overall, marijuana arrests have increased more than 150 percent since 1990.

You might think that increases in marijuana use prompt increases in arrests, or that increases in arrests lead to reductions in use. But judging from the federal government's own survey data, there is no clear relationship between the number of arrests and the number of pot smokers. Since 1990, a period during which arrests have risen more or less steadily, the number of Americans using marijuana in the past year has gone up and down, ranging from a low of 16.3 million in 1992 to a high of 25.8 million in 2002. Even allowing for methodological changes that seem to have boosted self-reported drug use after 2001, the number of pot smokers was no lower in 2006 than it was in 1990 and perhaps somewhat higher. Meanwhile, the risk of getting arrested for pot possession, as measured by the ratio of arrests to users, roughly doubled.