In 2001, shortly before Michael Bloomberg became a candidate for mayor of New York, an interviewer asked him if he'd ever smoked marijuana. "You bet I did," he said, "and I enjoyed it."

Yet as mayor, Bloomberg has presided over what a recent report from the New York Civil Liberties Union (NYCLU) calls a "marijuana arrest crusade," seeking to punish pot smokers for an activity he enjoyed with impunity. This little-noticed crackdown, which began under Rudy Giuliani, has disproportionately affected young black and Hispanic men, engendering resentment, distrust of the police and disrespect for the law.

While marijuana arrests have risen between two- and three-fold nationwide since 1990, the increase in New York has been much more dramatic. "From 1997 to 2006," sociologist Harry Levine and drug policy activist Deborah Small note in the NYCLU report, "the New York City Police Department arrested and jailed more than 353,000 people simply for possessing small amounts of marijuana. This was 11 times more marijuana arrests than in the previous decade."

Based on their analysis of arrest data and their interviews with police, arrestees and public defenders, Levine and Small conclude that the pot busts are largely a byproduct of the NYPD's aggressive "stop and frisk" tactics. The U.S. Supreme Court has ruled that police may briefly detain people they suspect of involvement in criminal activity and, as a precautionary measure, pat them down for weapons. Taking advantage of this Fourth Amendment loophole, New York City police stopped and frisked people more than half a million times in 2006.

In the vast majority of cases, these stops do not result in arrests. But sometimes people are carrying small amounts of marijuana. Since police cannot legally search for drugs without probable cause, Levine and Small found, they typically trick or intimidate people into revealing their pot, at which point they can be arrested.

Such trickery not only exposes the contraband; it changes the nature of the offense. Under state law merely possessing a small amount of marijuana (up to 25 grams, about seven-eighths of an ounce) is a citable offense similar to a traffic violation. But having marijuana "in public view" is a misdemeanor.

The NYPD makes about 35,000 such arrests each year. Although marijuana possession is either the only or the most serious charge in these cases, the arrestees are nevertheless handcuffed and taken to a police station, where they are fingerprinted and photographed, and they usually spend a night in jail, an uncomfortable, degrading and often frightening experience. Continued...