The analysis uses a cost-minimization model that aims to minimize over time the sum of the direct social loss from heroin addiction plus the cost of policies designed to reduce that loss. The model includes anti-supply enforcement as the only explicit policy. The analysis notes that in contrast to the implications of a static framework, dynamic considerations imply that under certain conditions, the legalization of heroin sales may be far from optimal. Although the optimality of permanent heroin legalization in general depends simultaneously on the strength of most of the relationships in the model, at least two circumstances, if found empirically, would support legalization regardless of other considerations. One would be a finding that anti- supply enforcement had no effect on the creation of addicts or the maturation of existing addicts. The second would be if the net current loss associated with an additional addict were negative under conditions predicted to prevail with no anti-supply enforcement at the maximum sustainable addict population. Figures, appended methodological information, notes, and 9 references