There are plenty of roadblocks to the reunion of Christians under one banner, and many will choose to point to one or another as the key point. Underlying them all, though, is the issue of authority. Whose interpretation of Scripture is correct? Why must we choose one interpretation over another? Is Scripture the sole infallible rule of faith, or does Sacred Tradition have a hold on us in conscience?
In defending the Protestant understanding of the individual priesthood of the believer, the anti-Catholic apologist James R. White states:
The individual priesthood of the believer does not mean there is no Church. It does not mean there are no pastors and teachers. It does not mean we are not to learn from one another, learn from the great Christians of the past, or “start from scratch” with every new generation. The doctrine does not do away with the … authority of elders to teach and train, nor does it give license to anybody and everybody to go out and start some new movement based on their own “take” on things. While this may happen, it is an abuse of the doctrine, not an application of it (White, The Roman Catholic Controversy , pp. 52-53).
However, the very abuse White decries is precisely the legacy of the individual priesthood as Martin Luther conceived it. And, as Devin Rose demonstrates in just over 150 pages, it's an inevitable consequence of the rejection of an infallible, authoritative Church.
(Full disclosure: Devin, who blogs over at St. Joseph's Vanguard, sent me the book to review.)
Devin begins the book by detailing his own gradual conversion to Christ from atheism, and his gravitation to Catholicism shortly after coming to faith. He also includes stories of other people either in transition or who have actually crossed the Tiber. But as interesting and heartening as those stories are, the main pulse of the book is the issue of authority, and most of the book is given over to it.
Because Devin attacks the problem of authority from several different directions, occasionally it looks like he's recovering previous points. That's inevitable; for instance, there's no separating the issue of the sacrament of confession without tying it back to Jesus' giving the Apostles the power to forgive sins, which also affects the problem of apostolic succession. Because he goes in different directions, and because these occasional repeats happen in different arguments, we don't get the effect of listening to Johnny One-Note on the kazoo.
The one necessary repeat is the phrase which is the title. Each time he reaches a midpoint or the end of a line of argument, Devin states, "If Protestantism were true ...", with the inevitably devastating conclusion. Nor does his line solely concern Scriptural proof-texts; he continually brings up arguments and testimony from the Reformers themselves, as well as statements from Protestant historians and authors. (One citation I was especially pleased to see was R. C. Sproul's trenchant characterization of the Protestant Bible as "a fallible collection of infallible writings".) He's also not shy about discussing the Church Fathers, who are very much the elephant in the Evangelical living room.
I read fast to begin with, so I devoured the book spine and all in just over three hours; a slower reader could finish it in a day, with ample time for reflection. It helps that Devin's writing style is very light and lucid, and that his tone is very engaging without being patronizing or acerbic. Over and over again, he reminds the reader that Protestants are not damned to Hell by mere dint of being Protestants, and that his interest is in fostering reunion.
All in all, Devin's arguments are clear enough that Catholics looking to defend the Church against Protestants should have this book on their shelves as a resource. At the same time, they're charitable enough that Catholics should recommend or give the book to Protestants who have their own questions on the matter.