A new study published in The Economic Journal vindicates the optimistic prognosis of cannabis activists that legalizing the herb would de-escalate drug war violence. The study notes a reduction in violence in US states along the Mexican border in recent years, and especially in the counties along the international line. The authors draw a connection to the reduced legal pressure on cannabis in the United States over this same period, thanks to legalization and medical marijuana laws. So could the end of prohibition mean the end of cartel violence?

Crippling the Cartels

The study, released late last year by a team from Pennsylvania State University and the Norwegian School of Economics, is entitled “Is Legal Pot Crippling Mexican Drug Trafficking Organizations? The Effect of Medical Marijuana Laws on US Crime.” It found that when a border state passed a medical marijuana law, violent crime fell by an average 13%.

“We show that the introduction of medical marijuana laws (MMLs) leads to a decrease in violent crime in states that border Mexico,” reads the abstract. “The reduction in crime is strongest for counties close to the border (less than 350 kilometres) and for crimes that relate to drug trafficking.

In addition, we find that MMLs in inland states lead to a reduction in crime in the nearest border state. Our results are consistent with the theory that decriminalisation of the production and distribution of marijuana leads to a reduction in violent crime in markets that are traditionally controlled by Mexican drug trafficking organisations.”

According to a Jan. 13 write-up on the study in The Guardian, the researchers examined crime data from the FBI and other official sources covering 1994 to 2012. They found that among the border states, the effect was most pronounced in California, where there was a reduction of 15% in violent crime, and weakest in Arizona, where there was a fall of 7%.

Of course, California’s medical marijuana law was passed in 1996, the first in the nation; Arizona did not follow until 2010. New Mexico got a medical marijuana program in 2007, and Texas in 2015.

What Does the Data Mean?

Overall, robbery fell by 19% in this period in border states with MMLs (which means all of them at this point), and murder dropped by 10%. Homicides believed to be related to the drug trade fell by an astonishing 41%.

Norwegian economist Evelina Gavrilova, one of the co-authors said that legal growers in these states “are in direct competition with Mexican drug cartels that are smuggling the marijuana into the US. As a result, the cartels get much less business.”

Gavrilova concluded: “Whenever there is a medical marijuana law we observe that crime at the border decreases because suddenly there is a lot less smuggling and a lot less violence associated with that.”

This is but the latest piece of evidence that vindicates critics of the “war on drugs,” who argued that lifting the pressure on cannabis would undercut the cartels. Evidence has also been seen in US Border Patrol stats showing a plunge in pot seizures since Colorado and Washington legalized cannabis in 2012.

If you are looking for the proverbial other side of the story, it is, of course, there. During this same period, heroin and methamphetamine seizures at the border have jumped. Some have argued that easy stateside consumer access to high-quality cannabis was prompting the Mexican cartels to switch to exports of meth and smack.

Even if that’s true, it must be weighed against the reality that as cannabis use has risen nationally over the past years, presumably due in part to relaxed legal pressure and erosion of the stigma, meth use has been dropping. Indeed, contrary to prohibitionist assumptions, even youth cannabis use has dropped in Colorado since legalization, possibly because the herb no longer has the allure of the forbidden.

Final Hit: Could The End of Prohibition Mean The End of Cartel Violence?