AP Photo

When I went to interview Tony Blair, the newly elected leader of the opposition in the House of Commons, in 1994, I wanted to ask him about his membership in the Christian Socialist Movement, a very traditionalist affiliate of the British Labour Party. I had, I told him, by now read all his speeches since he had become leader, and could find no trace of any such commitment in his rhetoric. With the very disarming open-faced grin that so many people would later come to dislike, he replied that this was because he couldn’t stand the sort of politician who exploited religion for electoral purposes. His administration would become partly defined by a terse response from his highly unsentimental media chief, Alastair Campbell, to...