A new book walks people through the latest Christian historical revisionists denying the separation of Church and State and distorting much of American history.
Rodda undertakes what an entire generation of professional historians, ensonsced and tenured in America's finest universities, has largely failed to do : acknowledge, confront, and refute the emergent school of Christian historical revisionism that amounts to the construction of an entire fictitious parallel history of the United States - with numerous interwoven and self-referential accounts claiming that the intention of the founders of the United States was to create an expressly Christian nation. One might suppose such a enterprise to have sprung from pages by Jorge Louis Borges or Philip K. Dick, but it is quite real and deadly, for that mythology has become firmly lodged in the minds of millions of Americans and so propels the political advance of Christian nationalism.I was amazed one day this summer to see a lecture by one of these, a Florida church leader, lying in front of a couple thousand people at his congregation about the founding fathers. Most of the founders were Deists, God set the universe running and then doesn't interfere. Only four, John Jay, John Witherspoon, Roger Sherman, and Patrick Henry, were what you might consider conservative Christians today, and even they were not Evangelicals. This was not what the reconstructionist said and in particular he was focusing on Jefferson, who famously cut up the Gospels to remove the superstitious parts. That also got left out of his sermon of founding fathers devoted to building a Christian Nation.
Another book recommended in the comments is "The Search For Christian America." The 3 authors of this are all religious historians and committed evangelical Christians and they gently rebuke followers of the restorationists.
The recent go-to book on the campaign to turn America into a theocracy is, of course, "American Theocracy."