420 FILE--Drugs and crime: The two phenomena have been linked for so long that many assume one inevitably leads to the other. Attorney General Jeff Sessions insists legalizing marijuana can inspire violent activity, while some in Colorado have linked legal pot to that state's increase in crime.

Fear-mongering? New research suggests as much. It provides evidence that legalizing cannabis in the state of Washington led to a significant decrease in criminal activity.

America is debating "the costs and benefits of a legal drug market," writes a University of Bologna research team led by economist Davide Dragone. "An increase in crime does not appear to be a plausible cost."

The study, published in the Journal of Economic Behavior and Organization, takes advantage of a two-year window (2013 and 2014) when recreational marijuana was legal in Washington, but illegal in the adjacent state of Oregon.

The researchers focused on counties on either side of the state border—10 in Oregon, and 11 in Washington—comparing crime statistics and data on alcohol and drug consumption.

They report legalizing pot "caused a significant reduction in rapes and property crimes on the Washington side of the border in 2013–14, relative to the Oregon side, and relative to the pre-legalization years 2010–12."

These drops were quite sizable: "It reduced rapes by between 15 and 30 percent (between two and four occurrences per 100,000 inhabitants), and thefts by between 10 and 20 percent (between 60 and 100 per 100,000 inhabitants."

Not surprisingly, the researchers report consumption of pot increased after smoking it became lawful. But the change in the law apparently decreased use of other drugs, and specifically reduced binge drinking.

The results echo those of another study released in January, which found the rate of violent crime fell in counties close to the United States-Mexico border after marijuana was legalized for medical purposes.

These latest findings offer no evidence as to why the change in law is having a positive effect, but the study's authors offer four possible explanations.

First, and most obviously, they note that, for most users, pot produces "a state of relaxation and euphoria," which presumably "reduces the likelihood of engaging in violent activities." (Unless you count brutally ripping open potato-chip bags during a bad case of the munchies.)  

"Second, this effect is reinforced if cannabis is a substitute for violence-inducing substances such as alcohol, cocaine and amphetamines," they write—a dynamic confirmed by their data.

"Third, the legalization of recreational marijuana may induce a reallocation of police efforts away from cannabis pushers and consumers, and towards other types of offenses," they note. And finally, it "may have reduced the role of criminal gangs and small criminals in local cannabis markets."

The researchers call this "first-pass evidence" of a link between legal pot and lower crime rates; more studies are needed. But at the very least, it suggests that, if they intend to slow this trend, anti-pot crusaders will need to come up with better scare tactics.

It's doubtful the frightening specter of higher home prices will cut it.

(Tom Jacobs is the senior staff writer of Pacific Standard where this was first posted. He specializes in social science, culture, and learning.)