A missionary may persuade a painted savage to worship a cross rather than an idol; but he will not make laws that send that savage's children to school, where they might learn to make the desert they inhabit another Eden by means of the advanced sciences. He may persuade his flock to love one another for his God's sake, but he'll invariably urge them to slaughter any neighboring tribe that still worships stone idols. This is the failure of religion as a force for the common welfare.

Part 3 The Island Out There Chapter 3 (p. 304) - Mendoza in Hollywood (2000)