The Religious Beliefs of America's Founders, by Gregg L. Frazer, joins the substantial and growing library of books on the religious faiths of the American founders. The public's fascination with this topic was evident long before the last founder was dead and buried, and it has waned little over the last two centuries. The founders' every action, from church attendance to private correspondence, has been studied and debated for what it reveals about their commitment to or departure from Christianity.

In our own time, Frazer writes, conversations on this contentious topic have been dominated by two camps. There are those who say, on the one hand, “that the Founders intended the United States to be a Christian nation built upon Christian and, specifically, biblical principles” (1–2), and those who contend, on the other hand, that the influential founders were deists who crafted a “godless” Constitution for a strictly secular polity. The thesis of Frazer's work is that the political theology of the American founding, in general, and the religious beliefs of “key founders,” in particular, were neither Christianity nor deism. Rather, a new belief system, which Frazer calls theistic rationalism, was at the center of the American founding. “Theistic rationalism,” he writes, “was a hybrid belief system mixing elements of natural religion, Christianity, and rationalism, with rationalism as the predominant element” (14). Adherents defined God in whatever way comported with their reason, and they were quick to set aside Christian beliefs that they did not regard as rational. This belief system “was not a popular system but appealed only to the well-educated elites … versed in Enlightenment thought” (14).

Frazer defines theistic rationalism in chapter 1, giving emphasis to how it contrasts with the basic tenets of orthodox Christianity and deism. This is a difficult task because theistic rationalism, like deism, is a belief system without an explicit creed, bishop, or authoritative text to articulate its fundamental tenets; indeed, it encompasses a range of sometimes inconsistent beliefs. Chapters 2 and 3 examine the European origins of theistic rationalism and its exposition by patriot preachers in the Revolutionary era. The key founders, Frazer contends, were not Christians insofar as they did not embrace the core doctrines “officially espoused by all of the major Christian sects in America in the 1700s” (17). Rather, they were theistic rationalists, and the next four chapters seek to show that John Adams, Benjamin Franklin, Thomas Jefferson, George Washington, James Madison, Alexander Hamilton, Gouverneur Morris, and James Wilson were neither deists nor Christians but were theistic rationalists. A concluding chapter highlights the influence of theistic rationalism on late eighteenth-century political culture and its residual effects on politics today.

Frazer's thesis is not new. Other scholars have expressed a need for a more nuanced accounting for the religious beliefs of the founders than simply a bimodal taxonomy of Christianity and deism, especially one that recognizes a hybrid system that drew on both Christianity and Enlightenment rationalism. Frazer acknowledges that scholars before him have coined and defined a variety of terms intended to describe this middle ground between orthodox Christianity and deism, using terms like providential deism, Enlightened Christianity, theological rationalism, Christian rationalism, and rationalist Christianity. Frazer provides a sophisticated description of theistic rationalism and argues that other terms fail to capture adequately the belief system of the major founders.

Frazer gives little allowance that the influential founders were anything other than theistic rationalists. He is dismissive of evidence or interpretations that challenge his thesis. Neglected in the study, for example, is the devout Congregationalist Roger Sherman, who by most measures deserves to be studied alongside the consequential founders that Frazer does profile. Consideration of a pious devotee of Reformed political theology like Sherman would have complicated Frazer's thesis. Other influential founding figures – such as Samuel Adams, Elias Boudinot, Patrick Henry, and John Jay – whose faith commitments might have challenged his thesis are similarly sidelined in his analysis. Nevertheless, Frazer usefully reminds readers that many influential founders were neither orthodox Christians nor deists; indeed, many embraced a political theology that drew on both Christianity and the Enlightenment.