The uncertainties associated with the precise nature of legalization regimes and with their expected outcomes sometimes are used to justify the maintenance of drug prohibition. This paper details the role that buyer licensing and exclusion might play in implementing a low-risk, post-prohibition drug regulatory regime. Buyer licensing and exclusion provide assistance to those who exhibit or are worried about self-control problems with drugs, while not being significantly constraining upon those who are informed and satisfied drug consumers. Relative to prohibition, licensing (...) and self-exclusion can be part of a drug regulatory structure that is much more finely tuned to the risks of harms stemming from drug use. (shrink)