In Law and Religion in American Society, Mark McGarvie seeks to trace the interplay of religion, law, politics, and American culture from the colonial era through to the present day. As such, the book does not lack ambition. It touches on, and raises key questions about, a wide range of important and interesting themes relating to the debates about law and religion in the United States. But ultimately the book cannot entirely fulfil its ambitious task.

“American culture,” McGarvie argues, “is rooted in two conflicting idea systems that can roughly be expressed as Enlightenment humanism and Christian moralism” (194). To the former, McGarvie attributes ideas of natural and individual rights, the primacy of the individual over society, and the creation of a public and private sphere with rights protected by being placed in the private sphere outside the influence of the state. By contrast, the latter emphasizes a form of communitarianism, of individual needs subordinated to the good of the whole, and of rights ordained by God. The tension between these two, McGarvie argues, has shaped the relationship between law, politics, and religion since the nation's founding – not least, he suggests, through the creation of a civil religion: “at once both a betrayal of each idea system and an integration of the two, [which] has allowed Americans to hold onto their inconsistent ideologies while largely ignoring their irreconcilability” (194).

The development and shaping of these ideas, the conflict between the individual and society, and the emergence of a civil religion with elements of both faith and civic duty form the core of the book. McGarvie identifies four key time periods in the development of these ideas, each encapsulated in a separate chapter: the Revolutionary era to 1828, antebellum America, the Civil War through to 1937, and 1937 to the present day. In each, the key themes are returned to and McGarvie shows how the balance between them shifts over time according to the politics of the day.

This is not, however, a book for anyone new to the religious history of the United States. In covering the vast swathes of time encompassed by each chapter, the book does not have time to introduce readers in any detail to many of the themes, arguments, events, and people discussed: a certain degree of prior knowledge is required. Likewise, anyone new to the Supreme Court's twentieth-century religion clause cases might also find themselves somewhat baffled by the discussion of the consequences of those cases in the final chapter. This is a shame as the extensive sixty-nine-page bibliographical essay (longer than all but one of the substantive chapters) provides readers with an extensive, thorough, and useful introduction to the vast literature on the dual subjects of religion and law in US history. This would provide much of value to those starting out in this area, but the book's major content is likely to leave those without that knowledge already more confused than enlightened.

For those more familiar with the field, the book offers interesting, if not necessarily groundbreaking, arguments. McGarvie argues that the founding era “constituted arguably the most secular age in the history of the United States, and its primary laws and legal precepts embody that secularism” (xvii). With the exception of a small period during the rights revolution of the 1960s, he suggests, the nation has gradually moved away from those principles, driven by religious groups who wanted the state to reinforce its moral values or by secular groups who saw danger in excessive individualism. The overview of US history provided here works effectively to support McGarvie's thesis.

The book is at its strongest when focussed on these core arguments. But those arguments are not easy to follow and are not always as clearly connected across the time periods as they could be. Here the attempt to cover such broad swathes of history undermines the clarity of the argument being made. Shifts from political context, to religious developments, to legal changes, and back again leave the reader searching for the core threads that tie them all together, threads that are not provided by the author.

This isn't helped by the fact that for much of the book the “so what?” question largely remains unanswered. Why is it important that the founding era was secular? Why does it matter that religious and secular groups have made alliances throughout US history to achieve legal and political change? Why should we agree that “Lincoln probably did more to integrate Christianity into American culture, governance, and law than any other elected official in the country's history” (78)? What is the significance of the fact that the language of separation of church and state has been used to defend practices that actually merge the two? Why does it matter if the distinction between the public and private spheres is broken down? Only really to this last question does the book provide a clear answer (“As the founders created the private sphere to protect all rights, the erosion of the distinction between public and private spheres threatens them all” (197).) The questions’ relevance to current debates about religion and politics jumps off the page for anyone even vaguely familiar with modern church–state conflicts; that McGarvie does not make those connections explicit is a surprising omission. Clearer answers to these questions would also help to provide a driving force, and thus greater clarity, to McGarvie's argument that are currently lacking.

There is much to like in Law and Religion in American History but the reader is made to work hard to find it. This is a shame as the questions McGarvie asks about the ways in which religion, law, politics, and culture have interacted in US history and shaped the modern nation are important. Potential answers to those questions are hinted at in the book but their logical consequences are not drawn out, making it an interesting but frustrating read, and leaving the reader with the sense of a missed opportunity.