Why Do Protestants Convert?

By Brad Littlejohn and Chris Castaldo; foreword by Carl Trueman

$12.95 $9.95 (Pre-order discount)

Publication Date: December 12, 2023

About this book

An investigation of a troubling question

A strange phenomenon has gripped Protestantism in recent decades: many of its best and brightest thinkers have converted to Roman Catholicism. Likewise, many earnest, normal believers have found Protestantism shallow in doctrine, history, ethics, and worship, and made the leap to Rome.

How can Protestants make sense of this? In this short and penetrating book, originally published as a series of essays, Brad Littlejohn and Chris Castaldo insightfully diagnose the psychological, theological, and sociological factors behind Protestant conversions to Rome.

With refreshing honesty, they find many converts’ criticisms of contemporary Protestantism to be warranted, but argue that historic magisterial Protestantism has within it the answers to these objections and the resources for a Protestant renewal.

Paperback | 100 pp. | 5 x 8 | PubliSHed dECEMBER 12, 2023 | ISBN 978-1-949716-20-7

If you are interested in a bulk order please contact [email protected].

From the Book

“Regardless of the particularities of Newman’s conversion and the historically well-worn journey from Canterbury to Rome, however, there does seem to be something unique—and if you are a Protestant, uniquely unsettling—about the recent trend of what we might call ‘conversionitis.’ In thus labelling it, of course, we hardly mean to dismiss or pooh-pooh it. It is in large part the natural result of the self-inflicted wounds of the late 20th century scandal of the evangelical mind, which will take generations to undo. After all, each generation tends to define itself in relation to its parents’ generation, consciously or subconsciously reacting against it in various ways. For evangelicals of the early 21st century, the shallowness, subjectivity, and hypocrisy of Boomer-era Protestantism has been difficult to look past, and the increased urgency of our cultural moment has persuaded many, especially of our best and brightest, that they would be foolish to continue to lean on such a weak reed. Neither Jerry Falwell nor Mark Driscoll are of any use in defending us from the enemies that are now pounding at our gates, and Roman Catholicism still boasts a rich and robust intellectual tradition that can sustain both orthodox faith and evangelical politics. When all the efforts of the dwindling Roman legions could no longer protect Italy from the ravages of Attila the Hun, Pope Leo stepped into the breach, and who can blame the people of Western Europe for placing their faith in him? So it is today. There may well be resources in the Protestant intellectual tradition that equal Rome’s offering—certainly that is our contention at The Davenant Institute. But until we teach them effectively to our pastors, parishioners, and children, we should hardly be surprised when they go in search of greener pastures.”


Littlejohn and Castaldo fill a gap with this important book exploring why some leave Protestantism for another tradition. They do not trivialize, oversimplify, or condescend to this phenomenon. On the contrary, they take it with the utmost seriousness and show it must not be dismissed. Along the way, they challenge contemporary Protestant practice while simultaneously pointing to the riches offered in classical Protestantism. I highly recommend Why Do Protestants Convert? for all wrestling with ecumenical disagreements today, or seeking to help others in this process.

Gavin Ortlund, host of Truth Unites


Carl Trueman

  1. Conversionitis
  2. The Psychology of Conversion
  3. The Theology of Conversion
  4. The Sociology of Conversion
  5. A Way Forward

Afterword: Why Protestants Should Not Convert
Brad Littlejohn

About the Authors

Dr. Bradford Littlejohn (Ph.D., University of Edinburgh) is the Founder and President of the Davenant Institute. He also works as a Fellow of the Ethics and Public Policy Center and has taught for several institutions, including Moody Bible Institute-Spokane, Bethlehem College and Seminary, and Patrick Henry College. He is recognized as a leading scholar of the English theologian Richard Hooker and has published and lectured extensively in the fields of Reformation history, Christian ethics, and political theology. He lives in Landrum, SC with his wife, Rachel, and four children.

Chris Castaldo (PhD, London School of Theology) is Lead Pastor of New Covenant Church, Naperville, a fellow at the Center for Pastor Theologians, and visiting Professor at the London School of Theology. He has authored and contributed to several books, including: The Unfinished Reformation: What Unites and Divides Catholics and Protestants after 500 Years (co-written with Gregg Allison), Talking with Catholics about the Gospel: A Guide for Evangelicals (Zondervan, 2015), and The Upside Down Kingdom: Wisdom for Life from the Beatitudes (Crossway, 2023).

Carl R. Trueman is a professor of biblical and religious studies at Grove City College and a fellow at the Ethics and Public Policy Center.

Praise for this work

“This book is about more than conversion. It’s a perceptive survey of the challenges facing contemporary American Christians of all stripes. Catholics as well as Protestants will benefit from reading Why Do Protestants Convert?” 

– R.R. Reno

Editor of First Things

Why Do Protestants Convert? asks and answers a question that has troubled me for some time. As it explores the psychology, theology, and sociology of conversion, the book identifies key weaknesses in our churches that, taken together, make for something like a gut punch to contemporary evangelical Protestantism. Yet the authors also helpfully remind us there is no need to swim the Tiber, for there is nothing so toxic in today’s evangelical Protestantism that the magisterial Protestant tradition does not have the resources to cure.”


Research Professor of Systematic Theology at Trinity Evangelical Divinity School

“The phenomenon of evangelical intellectuals converting to Roman Catholicism is perhaps not massive in numbers, but still significant and well-attested beyond the United States. It signals some deficiencies in how the evangelical faith is perceived and lived out in its spiritual, ecclesial, and cultural aspects. So, this book is timely and needed. Littlejohn and Castaldo ask the right questions and provide insightful indications to help the reader approach the topic in a theologically informed way. They also help those who might be attracted to swim over to Rome to pause and think twice.

Without having an idealized view of the Reformation, the book challenges consumerist, individualistic, and shallow experiences of the evangelical faith and invites us to appreciate the rich legacy of historic Protestantism and its present-day vitality. At the same time, the book rightly argues that Rome is not that haven it is often portrayed by outsiders who sentimentally engage her. It is a dangerous place to stay away from. I commend Littlejohn and Castaldo for writing such a compelling case for Protestants not to convert to Roman Catholicism”


Director of the Reformanda Initiative, author of Same Words, Different Worlds: Do Roman Catholics and Evangelicals Believe the Same Gospel?

“In every era since 1517 adherents of the Reformation have sought what they thought to be a safer haven under the papal cloak, just as Roman Catholic contemporaries found their way to security in the promise of new life in Christ proclaimed by the Reformers. Littlejohn and Castaldo examine specific psychological and sociological contexts for Protestant conversions to the papal obedience in our time. They offer a convincing demonstration of the power of Reformation theology to offer the only true security in Christ’s death and resurrection and the bestowal of his benefits through God’s Word and trust in Christ alone.”

– Robert Kolb

Professor of Systematic Theology Emeritus, Concordia Seminary

“In an age when many Protestants feel a powerful pull towards Rome, it is necessary to understand both her appeal and the wealth of often untapped resources Reformational Protestantism has to meet—and eclipse—her charms. With wisdom and sensitivity, this book does that well, offering a helpful challenge for Protestants to be better Protestants.”

– Michael Reeves

President of Union School of Theology


The Davenant Institute endeavors to restore wisdom for the contemporary church. We seek to sponsor historical scholarship at the intersection of the church and academy, build friendships and facilitate collaboration within the Reformed and evangelical world, and equip the saints with time-tested resources for faithful public witness. Below are some of the works we’ve published towards that end.

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