The power possessed by the church during the middle ages was largely due to the control it had secured over domestic relations, and that no more severe blow has ever been inflicted upon it than the institution of civil marriage.... The Protestant pulpit is only less dangerous than the Catholic to the liberties of the people in that its organized strength is less. The old medieval control of the family under and through marriage is now as fully the aim of the Protestant church as of the Catholic.... The courts of this country have decided that marriage is a civil contract. As such a clergyman is no more fitted to take part in it than he would be to take acknowledgment of a deed, or take part in the legalization of any other contract. In fact a marriage performed by a clergyman of any denomination should be regarded as invalid in the light of civil law.
-- Matilda Joslyn Gage, "The Dangers of the Hour," refuting the Pope's and clergy's opposition to America's institution of civil marriage, quoted from Annie Laurie Gaylor, Women Without Superstition, p. 218-9. positiveatheism.org