In this country, political movements to legalize something are usually also social movements to normalize it. The most vocal supporters of drug legalization believe there is nothing immoral about drug use, even if they acknowledge the dangers of addiction (and some don’t even do that), while the most vocal opponents of legalization believe that drug use is both a threat to public health and a moral problem. A similar coincidence of moral and legal views obtains, mutatis mutandis, in the case of what legalizers call sex work and what prohibitionists continue to call prostitution: most of those campaigning to make it legal also believe that no social stigma should attach to either the sex worker or the client, while most who believe that prostitution is immoral can be counted on to believe that it should remain illegal.
This tight alignment between ideas about the law and ideas about morality is a distinctly American phenomenon. Outside of this country, it is not so uncommon to encounter people who do not believe prostitution is always immoral but nevertheless believe it should be prohibited for some other reason, perhaps because of its connection to human trafficking. Nor is it uncommon in other parts of the world to meet people who disapprove of prostitution but do not believe it should be illegal. The very liberal prostitution laws of most Latin American countries are widely accepted there, despite the fact that public disapproval of prostitution remains very high. This circumstance would surely strike many Americans as odd. But why should it? Why is there so little space between our own intuitions about the law and our intuitions about what might be called public morality (as opposed to the purely private, to-each-her-own morality that our public discourse passes over in silence)?
One possible explanation has to do with our cultural and religious pluralism. Law and commerce are perhaps the only two things that all Americans can now safely be assumed to have in common. Some have argued that the United States is today less a nation in the traditional sense than a multi-cultural commercial empire. But social stigmas against things like drug use and prostitution are cultural artifacts and therefore make sense only within the context of a common culture. The values Americans are still assumed to have in common, like equality and freedom, are all readily translatable into a legal idiom: equality before the law, freedom understood as a set of rights. In order to be intelligible to one another, we find it necessary to formulate our moral ideas in purely economic or legal terms—terms of equity, utility, and consent.
Another possible reason for the close alignment between legal and moral ideas has to do with our country’s pre-pluralist roots in Puritanism. To the Puritan mindset, law and morality are really the same thing. Just as the Constitution is the charter for our government, for the Puritan the Decalogue is the charter for all morality, a set of basic prohibitions from which we can derive other, more specific prohibitions. The Book of the General Lawes and Libertyes Concerning the Inhabitants of the Massachusets (1648), one of the earliest codes of criminal law in colonial America, begins with this observation:
So soon as God had set up Politicall Government among his people Israel he gave them a body of lawes for judgement both in civil and criminal causes. These mere breif and fundamental principles, yet withall so full and comprehensive as out of them clear deductions were to be drawne to all particular cases in future times.
The same document goes on to claim an equivalence between God’s laws and the laws of properly constituted civil authorities:
That distinction which is put between the Lawes of God and the lawes of men, becomes a snare to many as it is mis-applyed in the ordering of their obedience to civil Authoritie; for when the Authoritie is of God and that in way of an Ordinance Rom. 13. 1. and when the administration of it is according to deductions, and rules gathered from the word of God, and the clear light of nature in civil nations, surely there is no humane law that tendeth to common good (according to those principles) but the same is mediately a law of God, and that in way of an Ordinance which all are to submit unto and that for conscience sake. Rom. 13. 5.