The Dutch depenalization and subsequent de facto legalization of cannabis since 1976 is used here to highlight the strengths and limitations of reasoning by analogy as a guide for projecting the effects of relaxing drug prohibitions. While the Dutch case and other analogies have flaws, they appear to converge in suggesting that reductions in criminal penalties have limited effects on drug use-at least for marijuana-but that commercial access is associated with growth in the drug-using population.