Christian Natural Law and Religious Freedom: A Foundation Based on Love, the True, and the Good, by Alex Deagon. Routledge, 2025, 164 pages, $200.00.

Early American Presbyterians embraced religious liberty, even modifying the Westminster Standards to reflect those convictions. Although religious liberty became entrenched in the American constitutional order and remains widely protected in the United States and many other places today, influential voices on both the secular “left” and the conservative Christian “right” are raising serious doubts about it, or at least about its importance vis-à-vis other social-political priorities. Whether there are good reasons for religious liberty is a live question in contemporary political and theological circles, hence the relevance of this new book. Australian law professor Alex Deagon wrote it to promote a “sound theoretical foundation” (1) for religious freedom, especially through what he calls “Christian natural law.”

Part 1 lays the natural-law foundation of his subsequent treatment of religious liberty. Chapter 2 begins by noting that there is a long Christian history of natural-law reflection, but different writers and traditions have different emphases. While Roman Catholics focus on nature, tradition, and reason, Protestants tend to emphasize sin and grace. Deagon argues that these traditions are largely unified substantively and that their respective emphases complement each other. Thus, Deagon feels justified in speaking of a “Christian natural law,” which is rooted in Christian theological convictions and yet is also accessible to non-Christians since it is revealed in nature. Chapter 3 examines the work of several writers—both Christians and non-Christians—who present natural-law theories allegedly independent of whether God exists. Deagon argues that such attempts are ultimately impossible and that these writers have not avoided theology. Natural law theory, he claims, is intrinsically theological and thus never “theologically neutral” (62). In chapter 4, Deagon proposes that the foundational theological principles of love, the true, and the good form the content of Christian natural law. Here he introduces Radical Orthodoxy as an effective paradigm to capture these ideas. Radical Orthodoxy is a recent movement whose most prominent advocate is the British Anglo-Catholic theologian John Milbank.

Part 2 argues that Christian natural law is foundational for religious freedom, understood through these ideas of the good, truth, and love, respectively. In chapter 5, Deagon claims that religious freedom encourages people to pursue the good of religion, whose ultimate end is the beatific vision, that is, intimate eschatological communion with God. Religious freedom, Deagon says, also promotes the common good of our earthly societies by respecting and promoting inherent human dignity. Chapter 6 argues that religious freedom is good because its goal is pursuit of truth, and more specifically of true religion, which is knowledge of God and reconciliation with him. Finally, chapter 7 contends for religious freedom because love does not try to compel people to belief. “Coerced religion is not true or good religion” (152).

Deagon is correct about a number of important big-picture issues, in my judgment. He is right to insist that natural-law theorists cannot avoid certain kinds of theological judgments, even if they avoid speaking about God. God is the creator and upholder of the natural order, after all, and the law it communicates is his. We can be grateful that the content of the natural law—such as the immorality of murder and theft—impresses itself upon non-Christians, and Christians do well to take advantage of that as they participate in moral conversations in public life. But no one can really understand any law without accounting for the authority behind it. One might consider how ridiculous it would be to develop a comprehensive account of American law while trying to remain neutral on whether the United States Congress and Supreme Court actually exist.

Deagon is also correct to note the many important continuities in the natural-law theologies of different Christian traditions. With respect to the medieval theological inheritance, the way early Protestant writers viewed natural law was more similar to how they viewed the doctrine of Christ’s two natures in one person than to how they viewed the doctrine of justification. That is, they thought natural law was a Christian idea they could largely embrace from the earlier tradition without need for major reform. Whether Deagon has too quickly elided Roman Catholic and Reformed versions of natural law, however, is a valid question.

Perhaps most important is that Deagon is correct to defend religious liberty and deserves commendation for taking up the cause.

Nevertheless, several drawbacks impede the book’s overall effectiveness. For one, Deagon’s writing style makes the book difficult to read. Rather than offering his own tight, linear argument in support of his claims, Deagon often proceeds by reporting what one person after another has written about the issue at hand, thereby leaving readers to intuit an argument from these reports. I invite Deagon to take this criticism as an indirect compliment. He is an interesting thinker. This is his book, and I would like to hear more of his distinctive voice and less of a compilation of other people’s voices.

Second, Deagon engages very little with the long history of Christian opposition to religious liberty. In fact, one would not even know there is such a long history from reading this book. This not only gives a distorted picture of historical Christian attitudes toward religious freedom but also leaves readers unprepared to address the contemporary reemergence of some older arguments in favor of religious intolerance. On a related note, Deagon’s brief biblical argument for religious freedom (113–17) makes many good points but is fairly shallow and non-rigorous, and it does not address the arguments against religious freedom that many pre-modern Christians drew from Scripture.

Third and finally, I regret that Deagon offers his theological defense of religious freedom through the lens of Radical Orthodoxy. It is not an attractive perspective to my confessional Reformed eyes and not one I can recommend to Ordained Servant readers. Nevertheless, since Deagon apparently embraces Radical Orthodoxy, I am glad that he still argues strongly in defense of religious liberty. Readers familiar with Radical Orthodoxy may know that it is not the likeliest place to look for support on this issue. Sustaining religious liberty in any society requires people to defend it from different angles and with different rationales. In light of that consideration, I am grateful that Deagon adds his voice to the contemporary defense of religious freedom, even if his approach to its biblical and natural-law foundation is not exactly my own.

David VanDrunen is a minister in the Orthodox Presbyterian Church and serves as the Robert B. Strimple professor of Systematic Theology and Christian Ethics at Westminster Seminary California, Escondido, California. Ordained Servant Online, April, 2026