It is silly to suggest that morality cannot be legislated. Legislation *just is* the legislation of morality. Laws are formal promulgations of the convictions of the mighty regarding what is ill done, and by implication what is well enough done. Laws tell us what it is important to do, and what it is important not to do; by what they omit to cover, they tell us what is not important, what is in the eye of the Law neither here nor there. Statute by statute, they constitute a written and procedural record of a comprehensive moral vision of things.
Each law implies all by itself a comprehensive moral vision; for no one thing can be right or wrong except under a moral system that implicitly evaluates all acts as either good, bad, or indifferent. If for example we explicitly ruled out only murder, we would thereby implicitly evaluate all other sorts of acts as morally unobjectionable – as either good, or morally neutral (whether there can be such a thing as a morally neutral act – there cannot – is an argument for another day).
A comprehensive moral vision is impossible except under an exhaustively comprehensive vision of all things. Indeed: a comprehensive moral vision is nothing other than an integral aspect of some exhaustively comprehensive vision.
Such a vision need not be spelled out completely in order to be completely implicit in whatever is in fact spelled out. Perfect understanding of all things is not a prerequisite to any given jot of understanding, however small. But even the tiniest jot of understanding presupposes the complete intelligibility of all things, at least in principle, and to a mind sufficiently sapient (NB: nothing less than an infinitely sapient mind will do; no Principal of knowledge, then no principle of knowledge). If things are altogether unintelligible, then obviously there is no chance that they might be intelligible in part (NB: things that are absolutely unintelligible are eo ipso and absolutely inactual; they are not things in the first place).
An exhaustively comprehensive vision of all things includes a vision of God. It is then essentially and inescapably religious, in the sense that – at least implicitly – it avows religious propositions of some sort as, not just credible, but actually true.
Laws then all cannot but establish a body of religious doctrine, at least implicitly.
The antiestablishment clause of the First Amendment then is incoherent. Congress *cannot* pass a law that does not somehow formally establish the truth of some religious doctrine or other. At the very most, the First Amendment then can coherently proscribe laws that compel men to any explicit avowal of adherence to such doctrines, whether through utterances, or deeds, or payments of tithes or taxes, or acceptance of limitations upon their government service, or any other act. It can, i.e., coherently proscribe only laws that prevent men from renouncing their subjection to, and leaving, a polis that has established a moral vision of things, to which they cannot in good conscience subscribe. The First Amendment establishes the immutable propriety of any man’s decision to renounce his citizenship in the United States, and the protection of her laws.
The First Amendment insists that it is evil to prevent such renunciations. It is, in other words, itself a religious law.