The obvious thing to protect an ideal is a religion. The obvious thing to protect the ideal of marriage is the Christian religion. And for various reasons, which only a history of England could explain (though it hardly ever does), the working classes of this country have been very much cut off from Christianity. I do not dream of denying, indeed I should take every opportunity of affirming, that monogamy and its domestic responsibilities can be defended on rational apart from religious grounds. But a religion is the practical protection of any moral idea which has to be popular and which has to be pugnacious. And our ideal, if it is to survive, will have to be both.
– Eugenics and Other Evils (1922).