In his Against Establishment: An Anglican Polemic , Theo Hobson points to some hidden reasons why some fear disestablishment for the Church of England: “In a permissive society, the established Church is necessarily a permissive Church; otherwise it advocates social policies at odds with the law of the land and becomes a revolutionary sect. This is why many liberals fear disestablishment, despite knowing in their hearts it is right: it would jeopardize the Church’s commitment to the liberal values of the cultural mainstream.”
Now that is Constantinianism, and a great argument for disestablishment. Any church lacking the anatomical equipment to risk becoming a “revolutionary sect” deserves to be as marginal as possible.