"Drugs got enormously cheaper so users didn’t have to hit as many old ladies over the head and steal their pocketbooks," study author Travis Wendel, an anthropologist at John Jay College in Manhattan, told The New York World's Alexander Hotz, who wrote about the study titled "More Drugs, Less Crime." As Hotz reports, "the price of cocaine fell from $400 to $460 per pure gram in the early 1980s to less than $200 by the early 2000s. Similarly heroin dropped from $3,000 to $3,600 per pure gram in the 1980s to about $2,000 by the 2000s." And as the price of each drug fell, the rate of homicide, assault, and larceny in New York fell accordingly. When heroin cost about $1,072 for .04 gram in 1988,* there were 966.9 assaults in New York. In 2007, when the price of heroin hit $345.9 for .04 grams, there were 332 assaults per 100,000 people. Along the way, the price of heroin surged back in the early 90s, and the assault and murder rates did too, before all three tapered off.

*Note: There's been some confusion about the $1,072 figure mentioned above. Check the comments section for more discussion on that.

The paper argues that the border clampdown that started with the South Florida Task Force of 1981 led the major Colombian and Mexican cartels to switch from marijuana production to large-scale cocaine and heroin production because those drugs are physically smaller, easier to smuggle, and more profitable. "Other Reagan-era initiatives had the effect of increasing heroin production in Central Asia and increasing available Central American transshipment routes for South American drug production destined for US consumers," the paper argues. "The result was a huge increase in global production of heroin and cocaine and a consequent eventual drop in retail prices in rich/consumer nations."

Another Reagan-era policy, of spraying the herbicide paraquat on foreign drug fields, helped push the supply chain from focusing on marijuana to a focus on cocaine and heroin, the paper argues:

Efforts to eradicate marijuana, first in Mexico and later in Colombia, via spraying with paraquat, effectively crimped the supply chain and encouraged many Colombian growers to switch to coca, a plant that was much hardier in the face of spraying, and produced a more profitable product. The Reagan-era crackdowns on entry points mentioned above further encouraged the transition from the marijuana growing that had been traditional in Colombia.

Inside the United States, mandatory minimum sentencing remains pretty controversial. But the New York Police Department's spin on it, which Wendel and his team call a "war of attrition on street-level drug markets," actually seems to have succeeded in disrupting the drug trade -- not because everybody who could or would sell drugs was behind bars, but because it caused a huge labor headache for organized crime:

One generally unobserved but important outcome of the pressure that law enforcement applied to street-level drug selling organizations in the post-1987 period was the degree to which the greater turnover rate of employees engendered by the arrests affected the ability of the organization to make a profit. As trusted employees were locked up, the large heroin-selling organizations began to dip into the reserve army of labor (i.e., active heroin users) to replace them, but these new employees were far less trustworthy or reliable as effective street-level sellers.

Eventually it was the cost of staffing, combined with the decreasing value of their product, that led New York's major heroin dealing organizations to unravel, the paper argues, reducing crime between competitors. And with less organization and a flooded market, the price of the drugs went down (or rather, the purity went up -- Wendel points out a $10 bag of heroin still has about the same mass but contains much more dope than it once did) and the need to mug people and break into cars in order to buy your dope went down. It's not how most of us would have expected the war on drugs to work, certainly. And while the theory as to why is still up for debate (Wendel's paper hasn't yet been peer-reviewed), you can't argue with the numbers: New York is a hell of a lot safer than it used to be, and much of the rest of the country is, too.

This article is from the archive of our partner The Wire.