Two years ago, after publishing "Papal Sin"--a critique of the institutional Catholic church--
Pulitzer Prize-winning historian Garry Wills was inundated with mail. Many letters asked why he didn't leave a church he found so deeply flawed. His new book, "Why I Am a Catholic," is something of an answer to his detractors and supporters alike. Principally an historical analysis of the papacy, Wills' book also discusses how he and other Catholics can "believe in the church and yet differ from specific things specific popes have said."

Many American Catholics are grieved and disillusioned with the church right now because of the recent scandals. If a Catholic approached you saying he or she was considering leaving the church to become, say, Episcopalian, and you had to persuade them to give the Catholic church another chance, what would you say?

I would say "We need you. Don't give in. Don't let them win; we can win. Stay here." G.K. Chesterton, the British Catholic convert, said "The severed hand does not heal the body." We're all in this together; we have to correct our brothers [the bishops], and pray for them, and hope to bring them around. And we're sure we will, because the Spirit is guiding. Chesterton also says, "If I see my mother walking along a cliff, I don't say 'Yay mom, just go on as you're going.' I say 'Stop.'"

I don't shop around from church to church. I think that I am in the Mystical Body and that's the source of grace for me, and that's where I want to live. I can see other people validly being parts of other Christian denominations, which also have the Spirit, I'm sure, and working out their salvation and being much better Christians than I am. But I think that the Catholic church preserves the creed more faithfully than most other denominations.

In the book you say that, despite its great flaws, the papacy and the centralized nature of the Roman Catholic Church have helped it uphold doctrine better than other Christian churches. You cite the fact that some Protestant churches are losing the belief in the Trinity.

I think there's a little more attitude that you can take or leave what parts of the creed you want. An Episcopalian friend of mine said just jokingly, but still: "We Episcopalians can believe anything-but we rarely do."

What other beliefs are you worried about Christians as a whole losing?

Devotion to Mary is in the Creed and in the gospel, and some denominations don't have that. We Catholics have exaggerated that at times, but I think it's a valid thing: it's in scripture that she will be called blessed by all generations, so Marian devotion is a part of Catholicism that I like a lot.

And the idea of the interplay between grace and works has always been a problem when it comes to Catholicism and Protestantism. I find that the Catholic position is more reasonable to me.

You're a fan of works.

Of course, we're all saved by Jesus' sacrifice, not by our own, and by grace. But we can forfeit grace. Paul says: "I fear that having run the race I will lose." St Augustine said: "Don't kill heretics, give them a chance to repent." We can't say that so-and-so is saved and so-and-so is damned. It depends on free will.

One of the most interesting sections of "Why I Am a Catholic" discusses your seminary experience. The impression delivered was that at the time seminaries were hopelessly old-fashioned and out of touch--you mention that yours encouraged mortification. Today, many Catholics are alarmed with other issues relating to seminaries, saying they're not orthodox enough. In your ideal world, how would Catholic seminaries be run?

First of all, you would have to get rid of celibacy. Celibacy is a very unhealthy situation as it's now practiced. You would have to have married fidelity, chastity. You'd have to have a married priesthood, a female priesthood. And you could obviously have celibate priests if they choose it freely. "Let him who can take it, take it," is what Jesus said.

But celibacy was originally part of a vast ascetical discipline that was not connected to the priesthood. It arose in late antiquity as part of an amazing surge in popularity and enthusiasm [for ascetism], in the pagan world as well as Christian. This led to Desert Fathers and virgins scourging and starving themselves into mystic exultation.

These people became the heroes, the celebrities, the astronauts of the time. Priesthood was considered second-best, because priests were not Desert Fathers--heroic ascetics. What happened is that Athanasius and others tried to get the ascetics to become priests, and they said "no, that's the second best, we don't want to." So non-ascetic priests said we'd better start practicing some of these things or the people won't come to us, will not think we're authentic carriers of the gospel. So asceticism and celibacy came about by popular demand. But it was part of a whole culturally-conditioned scheme.