“The core of the argument,” Rafael Domingo tells his readers in the introduction to God and the Secular Legal System, “is the idea that secular legal systems should treat God, religion, and conscience with respect” (p. 1). According to Domingo, a secular legal system is one in which religious sources and legal sources are distinct and independent, and the purpose of a secular legal system is “to enable citizens to live and develop together within a single framework, despite disagreement over fundamentals.” Ultimately, the “assumption of a common human reason provides the epistemic justification for a legal system that does not depend on a religious legitimation” (p. 2). In 180 tightly-packed pages, Domingo explores how the secular legal system, epistemically grounded in a common human reason and therefore in no apparent need of religious legitimation, should relate to the concepts of God, religion, and conscience.

Domingo, the Spruill Family Research Professor at Emory University School of Law, takes a distinctive approach to these well-trodden topics. Rejecting alike what he calls the “religious approach” and the “secular approach” to jurisprudence, Domingo opts for what he dubs a “theistic secular” approach. He would put the American founders in the religious camp, seeing as how they frequently grounded the secular law in the transcendent laws of nature and of nature's God, while putting modern liberals such as John Rawls in the secular camp, since Rawlsian liberals seek to construct a theory of the state that does not rely on any comprehensive doctrine or theology. Domingo's proposed via media is for the secular legal system to acknowledge God as a meta-legal concept that has “a particular legal relevance that cannot be ignored by Western secular legal systems” while remaining agnostic about God's existence or nonexistence (p. 6). It is a kind of religious Rawlsianism, to coin a term, an attempt to construct a workable legal theory for a secular and pluralistic age that offers an intrinsic justification for the secular legal system to acknowledge the West's historic “cultural experience of God” (p. 11).

This all needs to be unpacked a bit, and Domingo does so in this short but dense treatise. Metalegal concepts are “ideas beyond legal systems that yet have legal implications,” he argues (p. 29). Western legal systems were built on assumptions about God's existence and attributes that developed from within the Abrahamic faiths and now extend to other forms of monotheism. Although we live in societies marked by reasonable disagreement about fundamentals, the idea of God as a metalegal concept helps explain and justify foundational concepts in our secular law, including: respect for the universe; the centrality of the human person; human dignity; human equality; moral freedom and responsibility; human solidarity; subsidiarity; human rights; and the distinction between church and state (pp. 32–44). Like God, religion and conscience are also metalegal concepts that exist beyond legal systems and yet have legal implications.

The consequences of Domingo's approach are different for God, religion, and conscience, respectively. Each is a distinct metalegal concept that calls for a different corresponding response from the secular legal system. In brief, according to Domingo, modern secular legal systems should recognize God, tolerate religion, and accommodate conscience. From a different angle, people in a secular legal system should be free to mention or invoke God in public life, exercise or practice religion, and follow the dictates of conscience in moral judgments. The chief way the state recognizes God is by acknowledging Him through ritual, symbol, and what the U.S. Supreme Court has called “ceremonial deism”—so long as this recognition does not itself violate someone's right to practice religion. Because secular laws often inadvertently impact religious practices, the main way the secular legal system can tolerate religion is by granting judicially-determined religious exemptions to facially-neutral laws. Finally, the secular legal system can accommodate individual's rational moral judgments, and the corresponding sense of moral obligation such judgments of conscience impose on the individual, through legal exemptions and privileges of abstention or conscientious objection.

As John Witte notes in the book's preface, Domingo's argument presupposes some crucial things about religion, law, reason, and morality that “have been and are fiercely contested” (p. xi). Would different assumptions yield different results? Yes, of course, as Domingo readily acknowledges by distinguishing his approach from competing religious or secular approaches. Although he briefly discusses the American founders as an example of the religious-approach (pp. 53–54), the founders' natural-rights social compact constitutionalism provides a distinct variation of the religious approach that would have been worth treating in more depth, even if only as a point of departure.

In a recent publication, Phillip Vincent Muñoz (“Two Concepts of Religious Liberty: The Natural Rights and Moral Autonomy Approaches to the Free Exercise of Religion.” American Political Science Review vol.110, 2.) argues that the political theory of the American founders recognized a natural, unalienable right to religious liberty that is incompatible with the modern approach of granting religious exemptions from generally applicable laws. Muñoz' argument, in short, is this: the American founders insisted that the state had no jurisdiction over the unalienable—and thus unalienated—right to religious liberty. There accordingly can be no judicial or legislative weighing of interests to decide whether to grant exceptions for religious free exercise, for that would presume that if the state has a compelling enough interest then it can regulate and infringe the right to religion.

Space will not allow for a fuller treatment of the founding era natural-rights theory of religious liberty, but the stark contrast between what Muñoz calls the founders' “natural rights jurisdictional approach” and Domingo's “theistic secular” approach came to mind when I reflected on this passage from God and the Secular Legal System:

The founders derived an unalienable right to religious liberty from mankind's prior duty freely to render worship to God. Domingo's “theistic secular” approach bases religious liberty on human dignity rather than a natural duty to God known to human reason. The end, or telos, of the legal right to religious liberty thus looks different from these different starting points, and the legal implications, as Domingo concedes, will look different as well. This is not to criticize Domingo's approach but rather to highlight the real-world implications of normative theory, a genre in which God and the Secular Legal System stands as a worthy contribution.