Thirty-five years ago, New York's legislature decriminalized marijuana possession. Numbers released last week show the New York Police Department continues to flagrantly flout that policy, wasting resources on a pointless, unjust, and illegal crusade against pot smokers.

Under the Marijuana Reform Act of 1977, possessing up to 25 grams of cannabis (about nine-tenths of an ounce) is a citable offense similar to a traffic violation, punishable by a maximum fine of $100. But if the marijuana is "burning or open to public view," that's a Class B misdemeanor, punishable but up to three months in jail. An officer who uses intimidation or coercion to convert the former offense into the latter, thereby providing a pretext for an arrest, is breaking the law.

Don't take my word for it. In a directive issued last September, New York Police Commissioner Raymond Kelly reminded the city's cops that "the public display of marihuana must be an activity undertaken of the subject's own volition." He said the charge is not legally appropriate "if the marihuana recovered was disclosed to public view at an officer's discretion."

Why did Kelly think it was necessary to remind his officers that they are supposed to follow the law? He was responding to complaints that police in New York manufacture misdemeanors by instructing people they stop to take out any contraband they might have or by searching them (ostensibly for weapons) and pulling out a joint or a bag of pot.

Such tricks help explain why pot busts have skyrocketed in New York City during the last decade and a half, even while marijuana use (as measured by government-sponsored surveys) has remained about the same. From 1997 through 2011, according to figures compiled by Queens College sociologist Harry Levine, the number of low-level marijuana arrests averaged about 39,000 a year, 14 times the average for the previous 15 years.

Based on interviews with "veteran New York City legal aid and public defender attorneys and supervisors from Manhattan, Brooklyn and the Bronx," Levine estimates that "two-thirds to three-quarters of the people arrested for misdemeanor possession" are busted in circumstances that Kelly himself says make the charge unjustified. Yet nine weeks after his directive, marijuana arrests were down only 13 percent compared to the same period in the previous year, and new data show the number for 2011 was 50,684, the second highest total ever.

Kelly seems unperturbed, suggesting that most of the arrests involve people brazenly waving their weed under officers' noses, although he concedes it's "very difficult to quantify" what fraction of the busts are legitimate. "Our clients are still regularly stopped [and] searched, and marijuana is recovered from their pocket," a Bronx public defender told A.P. last week. "At no point were they having it out [or] smoking it."

If such arrests are as common as they seem to be, most of the 400,000 or so pot smokers busted on Kelly's watch have been wrongly detained, wrongly fingerprinted, wrongly jailed, wrongly booked, and wrongly saddled with criminal justice records and all the attendant expense, inconvenience, and humiliation. Adding to the unfairness, these burdens are disproportionately borne by young black and Latino men, even though surveys indicate they are less likely to smoke pot than young white men.

The marijuana arrests are largely an outgrowth of the NYPD's "stop and frisk" program, which focuses on supposedly suspicious individuals in predominantly black and Latino neighborhoods. In New York City during the last three years, Levine calculates, blacks were seven times as likely to be arrested for marijuana possession as whites.

To stop these bogus busts, Assemblyman Hakeem Jeffries (D-Brooklyn) and state Sen. Mark Grisanti (R-Buffalo) have introduced a bill that would treat public display the same as possession for small amounts of marijuana. Kelly had a chance to show this legislation was not necessary, but it is abundantly clear by now that the NYPD cannot be trusted to decide whether pot smokers should be treated like criminals.

Jacob Sullum is a senior editor at Reason and a nationally syndicated columnist. Follow him on Twitter.

© Copyright 2012 by Creators Syndicate Inc.