The Religious Roots of the First Amendment opens with a snapshot of religious and political practice in three colonial American cities: Boston, Williamsburg, and Philadelphia. It is an effective way to introduce the larger concerns of this book, which traces a line from Martin Luther to James Madison, with stops along the way for such important figures as John Milton, John Locke, William Penn, Elisha Williams, Isaac Backus, William Livingston, and John Witherspoon. Running like a red thread through this nearly three hundred years of history is the Protestant notion of the right to interpret Scripture for oneself:

Of course, when it comes down to it, this isn't such a simple argument at all. It is a powerful and complex story, and Miller cogently traces the history of this singularly influential idea at the heart of the American constitutional tradition.

There is a great deal to applaud in Miller's account. The origins of religious liberty in religious duty (the existential importance that early Protestants attached to individuals' responsibility for their own salvation), the liberatory potential of Luther's thinking about the sanctity of conscience, the crucial role played by Baptist ideas of “soul liberty,” the influence of dissenting Protestant arguments on Lockean toleration: all of these aspects of Anglo-American toleration are deftly handled. Miller's emphasis on Milton, and his attention to such long-neglected (by political theorists, at least) figures as Leonard Busher, Penn, Backus, and Elisha Williams, are welcome. Livingston's role in the debate over Anglican control of King's College during the 1750s was crucial to issues of church and state, higher education, and the press in early America. And pairing Witherspoon's attendance at the Presbyterian synod with his protégé Madison's role in the Constitutional Convention (each man was in Philadelphia, for different reasons, in May 1787) skillfully interweaves history and biography in analyzing the new nation's political and religious structures.

No doubt historians of political thought will find Miller's tale familiar ground. Little in Religious Roots is new. But the book performs a valuable scholarly service in laying out the arc of this important Protestant tenet so clearly.

As with any attempt to cover three hundred years in 175 pages, there are some missteps. Miller glosses Luther's aggressive about-face toward Anabaptists (26), and repeats the fiction that Penn arranged a royal pardon for Locke (51), a myth debunked by Richard Ashcraft nearly twenty years ago. Locke surely did not counsel Penn on the Pennsylvania constitution (89), nor did the two “collaborate,” as Miller suggests (49). The swift succession in which Miller's chapters unfold makes careful consideration of other potential causal factors in the development of toleration virtually impossible.

Perhaps the most intriguing questions that Religious Roots raises are unanswerable. Miller makes clear that he does not argue “that the explanation for disestablishment can be limited to religion or theology” (4). Fair enough. But the cast of characters – Milton, Locke, Penn, Luther, and so on – is fairly rarefied, highly educated and conversant with questions of epistemology, theology, and ideas. Did religious liberty benefit from other, perhaps less intellectual, sources? Did the “free market of ideas” arguments he identifies in Livingston's thinking draw their power from actually existing free markets? And, if so, might we temper the causal claims that, despite Miller's demurral, seem implied in his close focus on texts and ideas?

Nor is the relationship between “dissenting Protestant religious ideals” (7) and “Enlightenment ideas” (7) entirely clear. Miller admits that “the distinction between Protestant and Enlightenment thought [regarding natural right] was not terribly clear” (98), and elsewhere refers to “moderate Enlightenment views and evangelical thought” as “Siamese twins” (117). At other times, he characterizes Enlightenment ideas – reason, skepticism, pragmatism, utilitarianism – as “elite” or as the property of “elite thinkers” (7), contrasting such elite views with popular religiosity: “The skeptical anti-clericalism of the French philosophers did not characterize the common man in the street in the American colonies” (5). Again, fair enough. But Miller acknowledges that we know very little about the views of “ordinary Americans” during the colonial period, and turns to “elite records of the type that accurately reflect popular views and opinions” (7), advancing the tenuous claim that “authors must argue from what they believe to be commonly held premises” (7). This methodological statement apparently allows him to identify any elite statement as reflecting “popular mindsets and assumptions” (8).

After so much information about these important ideas in the first five chapters, the book's conclusion is a combination of the tepid and the tired, with old saws about elite institutions and Hollywood moral relativism sitting alongside vaguely originalist constitutional invocations. The careful textual work of earlier chapters disappears in favor of sweeping generalizations like “[a]verage contemporary Americans believe in right and wrong, truth and error”; and denunciations of “the elite's embrace of relativistic secularity” (169). Miller presents an intriguing but puzzling schematic involving three “models” of toleration – with Locke and dissenting Protestantism occupying the sensible middle between Pufendorf's “pragmatic, anemic toleration” (157) and Bayle's skeptical (and therefore fragile) foundation for rights (161). But other than apparently assuming that we ought to approach church–state issues precisely as dissenting Protestants did, it is not clear what Miller would have us do in our own, very different, historical context.

There is a certain defensiveness in Miller's story, as if emphasizing religion in colonial history is somehow taboo. He seems to think that “tak[ing] religion and theology seriously as contributing to the shape of social and political ideas” (7) cuts against the grain. But the past several decades have seen a veritable explosion of scholarship placing religious belief and practice at the center of the story of the colonial settlements and the nation's founding. Rather than cutting against the grain, Miller's volume actually fits fairly comfortably into existing work that takes the religious elements of early modern political thought seriously. As such, it deserves a place on the shelf of all interested in the development of religious liberty in the Anglo-American tradition.