A Cannabis Crackdown Contracts

After rising dramatically, marijuana arrests are falling and the trend seems likely to continue.

In 1992, when Americans elected a president who said he had smoked pot without inhaling, the number of marijuana arrests in the United States began a steep climb. It peaked in 2007, during the administration of a president who refused to say whether he had smoked pot because he worried about setting a bad example for the youth of America. Since 2009, when a president who "inhaled frequently" because "that was the point" took office, the number of marijuana arrests has fallen steadily—a trend that continued last year, according to FBI numbers released this month.

It's not clear exactly why pot busts exploded during the last decade of the 20th century and the first decade of the 21st century, when the annual total rose from fewer than 288,000 to almost 873,000—a 200 percent increase. There does not seem to be any consistent relationship between the level of marijuana consumption and the number of arrests, the vast majority of which (nearly nine out of 10 last year) involved simple possession rather than cultivation or distribution. Judging from survey data on marijuana use, arrests did not rise in response to increased consumption; nor did the cannabis crackdown have a noticeable deterrent effect. The risk of arrest for any given pot smoker rose substantially between 1991 and 2007 but remained small.

In 1991, according to the National Household Survey on Drug Abuse (NHSDA), about 15 million Americans smoked pot. That year there were about 288,000 marijuana arrests, one for every 52 cannabis consumers. In 2007, according to the National Survey on Drug Use and Health (successor to the NHSDA), about 25 million Americans smoked pot. That year there were about 873,000 marijuana arrests, one for every 29 cannabis consumers.

Although the overall risk of arrest is small, it is decidedly higher for blacks and Latinos. In 2010, according to a report from the American Civil Liberties Union, blacks were nearly four times as likely to be arrested for marijuana possession as whites, even though survey data indicated they were no more likely to smoke pot. In some jurisdictions the black-to-white risk ratio was even higher. It was 8 to 1 in the District of Columbia, which helps explain the dramatic turnaround in black Washingtonians' opinions about marijuana legalization.

The good news is that the downward trend in marijuana arrests since 2009 seems likely to continue, helped along by the spread of decriminalization and legalization. In recent years California, Colorado, Maine, Massachusetts, and Washington have changed their marijuana laws so that people caught with small amounts are no longer arrested. That change has eliminated tens of thousands of marijuana arrests each year—more than 50,000 in California alone. Under ballot initiatives approved this month, Alaska and Washington, D.C., will eliminate all penalties for possessing small amounts of marijuana. (Possessing up to an ounce was already a citable offense in Oregon, where voters also approved marijuana legalization this month.) In 2016 marijuana legalization is expected to be on the ballot in several more states.

Even in New York City, where the cannabis crackdown has been especially noticeable, police are arresting fewer pot smokers, a trend that is likely to accelerate as a result of a policy change that took effect last week. Low-level marijuana possession arrests by the New York Police Department (NYPD) skyrocketed from about 3,000 in 1994, when Rudolph Giuliani took office as mayor, to more than 51,000 six years later. The crackdown continued during Michael Bloomberg's administration, when the NYPD arrested an average of nearly 39,000 pot smokers each year, compared to 24,487 under Giuliani, 982 under David Dinkins, and 2,259 under Ed Koch, according to data gathered by Queens College sociologist Harry Levine.

On the face of it, this huge increase in pot busts was puzzling, since the New York legislature decriminalized possession of up to 25 grams (almost nine-tenths of an ounce) in 1977, making it a violation punishable by no more than a $100 fine. But possessing marijuana that is "burning or open to public view," a.k.a. "criminal possession of marihuana in the fifth degree," remained a Class B misdemeanor, punishable by a $500 fine and up to three months in jail. That is the provision New York cops typically use to bust pot smokers.

Why did arrests for public display of marijuana rise so dramatically? Perhaps cannabis consumers suddenly became more brazen in the mid-1990s, waving their weed under cops' noses to a much greater extent than before. Perhaps they always carried their cannabis conspicuously, and cops suddenly decided they would no longer accept such ostentatious violations of the law. Or perhaps cops started to bust people for having marijuana "open to public view" after patting them down or instructing them to empty their pockets during street stops.

Those explanations are not mutually exclusive, but reports from defendants and their lawyers suggest that the practice of transforming violations into misdemeanors by bringing marijuana into "public view" was pretty common. It was common enough to generate an extraordinary 2011 directive from Ray Kelly, Bloomberg's police commissioner, reminding his officers that such trickery is illegal. "To support a charge [of criminal possession], the public display of marihuana must be an activity undertaken of the subject's own volition," Kelly wrote. "Thus, uniformed members of the service lawfully exercising their police powers during a stop may not charge the individual with [criminal possession] if the marihuana recovered was disclosed to public view at an officer's discretion."

It so happens that 2011 was the peak year for pot busts during the Bloomberg administration, so maybe Kelly's memo had an impact. Low-level marijuana arrests fell from more than 50,000 in 2011 to fewer than 29,000 in 2013. The decline also coincided with a sharp drop in stop-and-frisk encounters—which, like pot busts, overwhelmingly involve blacks and Latinos.

This month Mayor Bill de Blasio, who during his campaign promised to change the "unjust and wrong" practice of busting cannabis consumers for carrying small amounts of marijuana, announced that from now on they will generally be cited for a violation instead. De Blasio and his police commissioner, Bill Bratton, who also ran the NYPD when the city's cannabis crackdown began under Giuliani, said misdemeanor charges will be reserved for people caught smoking pot in public.

Police union officials were not pleased by De Blasio's decision to ease up on cannabis consumers. "I just see it as another step in giving the streets back to the criminals," Michael Palladino, president of the Detectives' Endowment Association, told The New York Times. "And we keep inching closer and closer to that."

Ed Mullins, president of the Sergeants Benevolent Association, had a similar reaction to a recent report that the NYPD will no longer use "buy and bust" tactics to nab small-time pot dealers. "If the current practice of making arrests for both possession and sale of marijuana is, in fact, abandoned," Mullins told the New York Post, "then this is clearly the beginning of the breakdown of a civilized society."

A little historical perspective suggests that such apocalyptic warnings are premature. The NYPD could cut low-level possession arrests in half and still bust a lot more pot smokers than it did in any year prior to 1997. Likewise, last year's nationwide total of 693,000 marijuana arrests, although one-fifth lower than the number in 2007, was still more than twice as high as the 1991 tally. Furthermore, a recent study by Jon Gettman, a professor of criminal justice at Shenandoah University in Virginia, found that marijuana arrests rose in some states between 2008 and 2012 while falling in others. The end of civilization may be further away than Mullins and Palladino think.

This article originally appeared at Forbes.com.