And that's what irritates and frightens the hell out of the powers of the world: the newspaper editors and the college professors and the political activists, all of religion's cultured despisers, all the people who think they have this modern world wired. Faith they can deal with: an illogical remnant of bygone ages, to be admired in other cultures and mocked in our own. But an idea, that's a problem. An idea can change the world. 

When the European press deluged the world in 2010 with reporting on priestly crimes, mostly from the 1970s and 1980s, the lesson was not just that members of the Church had done great wrong. Lord knows, they had. But most Catholics understood that something in the modern world hates the sheer idea of Catholicism — the alternative and the indictment it poses. Indeed, the feeling that Catholics have is one of being under constant attack, as though someone had declared "Ecclesia delenda est."

The curious thing is that neither the beleaguered Catholic faithful nor the anxious rejecters of religion are wrong exactly. The public battles over Catholicism during the 50 years since Vatican II have all been finally a clash of ideas about the modern world — and each side, the Catholic and the anti-Catholic, is death to the other. That's what George Weigel shows in The End and the Beginning (Doubleday, $32.50), the final volume of his magisterial biography of John Paul II. During the Cold War, the Soviets had long been suspicious of Karol Wojtyla, but after his election as pope, Weigel notes, they saw clearly he was "a moral threat to the communist position in central and eastern Europe, to the communist project throughout the Third World, and indeed to the very survival of communism itself."

John Paul was a philosopher, by training, and Benedict is a theologian — a serious, world-class academic — and though they differ greatly in the personality of their papacies and the focus of their interests, they share something that Pius XII, John XIII, Paul VI, and even the short-lived John Paul I lacked. The four popes from 1939 to 1978 were all fundamentally churchmen: public intellectuals and commentators, yes, but, at root, they were all trained as bureaucrats for the Church. The two popes since were both people who thought first in terms of ideas. They were, in essence, intellectuals, acting on a world stage. They didn't create the Catholic idea, of course, and neither did they bring into existence the intellectual role that Catholicism is playing today in public debates. It was, rather, a case of the times finding the men it required.