Less than two weeks before Colorado voters decide whether to legalize marijuana in that state, a new report highlights one important reason they should vote yes: Even though Colorado supposedly "decriminalized" marijuana possession in 1975, police there continue to arrest more than 10,000 pot smokers every year. That's because possession of small amounts (less than an ounce at first, two ounces since 2010) remains a crime, albeit a "petty offense." The report's authors, Queens College sociologist Harry Levine and Jon Gettman, a professor of criminal justice at Shenandoah University, explain:

A person charged with possessing marijuana is issued a summons to appear in criminal court. The court appearance is mandatory and failure to appear is another crime, a Class 3 Misdemeanor, punishable by six months in jail and a $500 fine…. Police departments have discretion as to whether they charge under state or municipal law, and in some municipal courts marijuana possession is punished more harshly than in county courts where state law applies. In the city of Lakewood, for example, possession of a small amount of marijuana can be punishable by $1,000 and one year in jail. In many cities, municipal courts typically impose fines of $300 or more for a first time marijuana possession charge. It is not unusual for municipal judges to place people on probation for up to six months, charge them $50 per month in probation fees, [and] require that they meet with a probation officer and submit to regular drug testing. Some judges send people to jail for several days for failing a drug test for marijuana…. Marijuana possession arrests create criminal records easily found on the internet by employers, landlords, schools, credit agencies, licensing boards, and banks, erecting barriers to education, employment, and housing.

Levine and Gettman count 210,000 marijuana possession arrests in Colorado since 1986. Following a national trend, pot busts in Colorado have risen dramatically since the early 1990s, from less than 4,000 in 1992 to about 10,500 in 2010; the peak year was 2000, when there were more than 12,000 marijuana possession arrests. As in New York City and California, the arrests are racially skewed: Blacks are more than three times as likely as whites to be charged with marijuana possession, even though survey data indicate they are no more likely to smoke pot. More generally, the burdens of enforcing marijuana prohibition are arbitrarily distributed, landing on the unlucky few who happen to be caught. Data from the National Survey on Drug Use and Health indicate that 10 percent of Coloradans consume marijuana every year, amounting to about 368,000 people. (The actual number is probably higher, since people may be reluctant to admit illegal behavior even in a confidential survey.) That means less than 3 percent of pot smokers are arrested in any given year. When a "crime" is committed each year by at least a tenth of the population, 97 percent of whom get away with it, it probably should not be treated as a crime, especially when it violates no one's rights and most people think it is not the sort of behavior that justifies an arrest.

In addition to legalizing possession of up to an ounce, Colorado's Amendment 64, which was supported by 48 percent of voters in the most recent survey, would authorize state-licensed pot shops. You could eliminate all the possession arrests counted by Levine and Gettman without taking that step, but only by accepting an egregious moral inconsistency: If consuming marijuana is not something for which people should be punished, how can it possibly be just to punish people for aiding and abetting that noncrime?