> All of this stems from religion, yet our system is supposed to have a separation of church and state. Restrictions on prostitution are pretty far downstream

> All of this stems from religion, yet our system is supposed to have a separation of church and state. Restrictions on prostitution are pretty far downstream of core church-state separation territory. The original constitutional prohibition is "Congress shall make no law respecting an establishment of religion" ("establishment clause") "or prohibiting the free exercise thereof" ("free exercise clause"). The core territory of the establishment clause is that there can't be an official state church or an officially designated state religion. Later court cases extended that by analogy to require fairly broad religious neutrality, as well as to avoid various forms of "entanglement" between church and state. But so far, there's no official interpretation of it that implies that laws that were originally motivated by religious sentiment or religious morality are invalid. (If I remember correctly, Scalia's dissent in Obergefell expressed concern that the majority was gesturing in that direction, although the majority definitely didn't phrase it that way.) Particularly, there's no clear constitutional law that all legislation always has to be justifiable in terms of addressing a harm (usually that only comes into play when another constitutional right is implicated). I agree with the idea of legalizing prostitution and I agree with the idea of separation of church and state, but I don't think you can directly get one from the other.