Legalizing drugs harms some black markets but spurs activities in others:
It is widely hypothesized that legalization disrupts illicit markets and displaces illegal suppliers, but the consequences for those who are displaced remain poorly understood. In this paper, I use comprehensive administrative data from three states that legalized marijuana covering all individuals released from prison in the years immediately before and after the policy change to estimate the effect of legalization on the subsequent criminality of convicted dealers. I find that marijuana legalization increased the 9-month recidivism rate of marijuana offenders by 6 percentage points relative to a baseline rate of 10 percent. The increased recidivism is largely driven by a substitution to the trafficking of other drugs, which is consistent with a Becker-style model where individuals develop human capital specific to the drug industry. To learn about potential mechanism behind these results, I use detailed drug transaction price data to estimate the effect of legalization on average prices and price dispersion, and I find suggestive evidence that both the average level and residual variance decline following legalization, which is consistent with legalization eroding rents earned in the illicit marijuana market. Lastly, I explore the generalizability of my findings in a distinct legalization experiment from history: the end of National Prohibition. I replicate the main insights at an organizational level and show that, in response to the repeal of Prohibition, the Italian-American Mafia shifted personnel from bootlegging to narcotics. Overall, the results in this paper suggest that an unintended consequence of drug legalization is a re-allocation of drug criminals to other illicit activity.
That is from Heyu Xiong, who is currently on the job market from Northwestern.