In an article published early online by Lancet Public Health, former NIDA U.S.–Mexico Drug Abuse Research Fellow Annick Borquez, Ph.D., and colleagues concluded that the Mexican drug law reforms of 2009 have had a negligible effect on the HIV epidemic in Tijuana. The law allows for personal consumption of certain drugs and mandates drug treatment rather than incarceration after a third apprehension. The authors found that between 2012 and 2017, the new law averted only 2% of new HIV infections among people who inject drugs (PWID). Using epidemic modeling, they predicted that 21% of new HIV infections could be prevented between 2018 and 2030 if PWID were referred to opioid agonist treatment instead of incarceration. They noted, however, that implementation of the 2009 law was marred by lack of police training and lack of evidence-based drug treatment. Beginning in 2014, “treatment” consisted of compulsory abstinence, which has proven to be detrimental in other settings and in Tijuana often involved police abuse and traumatic experiences for PWID. The authors predict that continuing to rely on compulsory abstinence could potentially increase the number of new HIV infections by as much as 2% between 2018 and 2030. An accompanying commentary reminds policymakers and researchers that it is imperative to monitor and evaluate the implementation of policy reforms. Read the open access article.