State adult-use cannabis policy effects on law enforcement efforts to disrupt drug markets

Abstract

BACKGROUND: Legalizing cannabis impacts law enforcement strategies on drug deterrence. While cannabis possession arrests have fallen post-legalization, findings on racial disparities are mixed. No research has yet investigated cannabis legalization effects on police behavior in the form of drug seizures, or how it may influence the enforcement of other drugs. We sought to evaluate the effect of cannabis legalization on drug seizures and their related disparities by race to understand how law enforcement have adjusted to this rapidly shifting legal landscape.

METHODS: Drug seizure data were collected from the National Incident Based Reporting System (NIBRS) and include state, race, and drug types from 16 states with over 95 % population coverage for 2017-2022. Treatment and control assignments were determined by whether cannabis had been legalized for adult use between 2017 and 2022. Log seizure rates and Black-white risk ratios were calculated using census data. Two-way fixed effects difference-in-differences models robust to multiple treatment periods evaluated the effect of cannabis legalization on seizure rates and Black-white risk ratios.

RESULTS: Our findings indicate that cannabis legalization significantly reduced overall drug seizures, particularly those involving cannabis. Of the other seizure types tested, only one non-cannabis drug seizure rate type was significant. We found a moderate yet significant decrease in the Black-white risk ratio for cannabis seizures, though all other racial disparities in seizure rates persisted after the legalization of cannabis.

DISCUSSION: Cannabis legalization was associated with reduced drug seizures overall, driven by a large reduction in cannabis seizures. There was also a significant reduction in the Black-white risk ratio for cannabis seizures, though Black individuals remained at higher risk for all drug seizure types compared to white individuals. While expected to decrease without cannabis smell to prompt seizures, non-cannabis drug seizures were unchanged except for an increase in methamphetamine seizures not involving cannabis, potentially due to shifting enforcement priorities. These results suggest that cannabis policy reform can alleviate law enforcement burdens and may improve racial disparities in drug seizures to a small extent yet highlight the continued necessity for policies addressing systemic biases in drug enforcement.