"The eventual construction of a national identity, or a national culture, involved many factors, but one that contributed almost nothing was the religion practiced by the founding fathers themselves." So says Mark Noll, revealing what ought to have occurred to countless thoughtful people at every level of discourse. The Founders, however broadly you want to construe that category, were not ministers, they were not religious leaders, they were not spokesmen for the nation’s faith. They were political theorists, in their best moments, and more often simply politicians much of the same sort we have today. They never presumed to speak for the nation or even to be representative of it. They meant only to construct a government and then to commend that government to the people for their approval and interpretation.
It is in this latter role that the real folly of tying the religion of the nation to the religion of the Founders becomes evident. When we examine only the Constitution and the thought of its various authors, we ignore that they did not invest it with its significance or even its authority. Only when referred to the people does the Constitution become representative of and normative for American government. Therefore whether or not the Constitution, and thus the government it defines, is a purely secular one rests not with the authors but with those who interpreted and applied it. In describing his purpose in writing God of Liberty, Thomas Kidd points out, "So much of the popular discussion of faith and the American Founding revolves around the personal faith of the major Founders. This is an interesting topic, but I don't actually think it tells us much about the role that religion played in the larger process of creating the American republic. So I sought to broaden the focus to the level of the public religious principles that helped unite the Patriots. These included religious liberty, the importance of virtue, the dangers of vice, the principle of equality by creation, and the role of Providence in human affairs." These popular religious notions are infinitely more important because their influence on the development of a national identity and control over politics at every level were more direct.
Yet, as Kidd points out, these common religious notions actually unified Christian and secularist alike: "When you look at these principles, it is easier to understand why people of such sharply differing personal beliefs as Thomas Jefferson and the Baptist evangelist John Leland could cooperate so enthusiastically during the Revolution." If the interest in the faith of Jefferson and Madison is intended to establish whether or not America was founded on Christian principles, the explicit faith of either is largely inconsequential. It takes a person of profound historical ignorance to assume that when Jefferson and others appeal to Nature and Nature's God in an effort to discover the universal principles which ought to govern human relations, their vision of that universal God is Christian. It may be diluted and contorted, but it is not the same vision of a secular "Creator" that they would construct had they been Hindu or Muslim or even Jewish. Jefferson was quite clear that he believed Jesus to be a uniquely qualified revealer of the true nature of the world and ethics. The principles that guided his political thought were the principles of Christianity filtered through the prism of eighteenth century natural theology, even and especially the principle of religious pluralism. Consider the argument of Catherine A. Brekus and W. Clark Gilpin: "Christianity in America is not neatly contained under the steeples of its churches or the governing bodies of its denominations but has, in addition, extended out into other sectors of society. If Americans do not always recognize the Christian influence on their culture, it is because its omnipresence has made it virtually invisible."
Ultimately, it ought to be clear that the religious thought of the Founding Fathers, while interesting in itself, is not particularly relevant to the question of whether or not America is a Christian nation. There are other more pertinent questions we might ask. What did the people who ratified and applied the Constitution believe about the Christian character of the nation? What distinctively Christian impulses or thought modes governed the apparently construction of an apparently secular Constitution? Of course, as I argued previously, the question of first importance needs to be why do we care at all what eighteenth century Americans thought and, if it is important, what is a responsible way to apply that information? Still, Stephen Prothero comes closest to providing answers about the Christian character of the republic from its outset, doing so in a way that displays a delightful penchant for Christian paradox:
There is logic not only to President John Adams’s affirmation in the Treaty of Tripoli in 1796 that “the government of the United States of America is not in any sense founded on the Christian religion” but also to the Supreme Court’s 1892 observation that “this is a Christian nation.” In short, the long-standing debate about whether the United States is secular or religious is fundamentally confused. Thanks to the establishment clause, the US government is secular by law; thanks to the free exercise clause, American society is religious by choice. Ever since George Washington put his hand on a Bible and swore to uphold a godless Constitution, the United States has been both staunchly secular and resolutely religious.