All that I have to add is that the New England Primer was the school textbook of the age and for another hundred years or so. In their formative years, this is what they would have used to learn how to read and write. And it is very Christian and includes some disturbing anti-Catholicism as well.
We've come a long way, baby.... But whatever we've become, it is crystal clear to me that this nation's founding ethos was thoroughly Christian.