Following on from yesterday, I stumbled across this paragraph from Mennonite theologian John Howard Yoder, who sums up the movement of Christianity from marginal religion of shared conviction to imperial religion of shared interest:
Before, Christians had been a minority - some scholars estimate more than ten percent of the empire's population - and intermittent persecution worked against making anyone's adherence cheap. It took at least a degree of conviction to belong. After Constantine the church was everybody. Being counted as "Christian" was the rule, not an exception. Paganism was soon declared illegal, and within another century the government was actively repressing heresies, i.e., ruling on what constitutes orthodox belief and punishing dissent. Henceforth, it would take exceptional conviction not to be counted a Christian.
Christians are moving/have moved back to the margins of society for the most part, but with one crucial difference: we are now on the margins of a society which is itself the creation of Christianity. The son has turned his back on the father, but unlike the son of the parable, this son had good reason.