My idea is that it wasn’t so much a Christian Nation as that Christianity was pretty much taken for granted by the vast majority.
I do think Christian influences were clear.
I’m not going to claim that God wrote the US Constitution. But the Hand of God clearly permeates that sacred “manual of Conservatism”, aside from the the amendments pushed through by the anti-American liberal element. The despicable William Jennings Bryan, who falsely claimed to a man of God, was among those who advocated the so-called “progressive” movement. In reality, it was regressive and set the stage for America’s move to third world status.
The great awakeing occured in 1730’s in america. according to wiki which looks fairly accurate:
Additionally, pastoral styles began to change. In the late colonial period, most pastors read their sermons, which were theologically dense and advanced a particular theological argument or interpretation. The leaders of the Great Awakening, such as James Davenport, Jonathan Edwards, Gilbert Tennent and George Whitefield, had little interest in merely engaging parishioners’ intellects; rather, they sought a strong emotional response from their congregations that might yield the workings and experiential evidence of saving grace. Joseph Tracy, the minister, historian, and preacher who gave this religious phenomenon its name in his influential 1842 book The Great Awakening, saw the First Great Awakening as a precursor to the American Revolution. The evangelical movement of the 1740s played a key role in the development of democratic thought, as well as the belief of the free press and the belief that information should be shared and completely unbiased and uncontrolled. These concepts ushered in the period of the American Revolution. This contributed to create a demand for religious freedom.[5] Although the Great Awakening represented the first time African Americans embraced Christianity in large numbers, Anglican missionaries had long sought to convert blacks, again with the printed as well as the spoken word.