Should (and Could) We Ban Prescriptions?

In a simple model of social interaction I analyze the welfare effects of positive (prescriptive) and negative (proscriptive) social norms, together with the private incentives for their enactment. I find that imposing no law is socially optimal when individual actions have no significant externalities, while bans become socially optimal as the externalities increase. Prescriptions are generally the worst choice, except when the externalities involved are very high. However, in the political arena support is rarely won for non intervention or for a ban, since an alternative majority will generally be found in favor of some prescription. This remains true even when strategic voting is considered, and provides an argument for the idea that a liberal state cannot be liberally enforced by rational voters.