One of the costs of anticipated amnesties is current and future non-compliance with the law. Relatively to a no-amnesty situation, efficient enforcement policies may therefore differ when an amnesty is offered. To study this question, a model is built in which individuals impose a cost on society when they commit a crime. When a criminal participates in an amnesty, or (to a lesser extent) when he is caught, some fraction of the social cost is recovered, reflecting co-operation with the authorities. The analysis characterizes efficient anticipated amnesties. It is shown that the efficient level of enforcement may be smaller in the case of an anticipated amnesty than in a no-amnesty situation. The reason is that despite the increase in the initial number of criminals generated by the amnesty, many criminals eventually participate in it. If participants in the amnesty are very co-operative, then a large proportion of the social cost is recovered making the initial increase in the number of criminals less costly. The optimal level of the reduced sanction imposed on those who participate in the amnesty is also characterized. Copyright Kluwer Academic Publishers 2000
