The foundation was laid long ago by atheists, deists, "theists", freemasons, and other rejectors of traditional religion in favor of some nebulous theistic/deistic "God" or, as we now see, no God at all.
I have to take a mild disagreement here. I consider myself to be a Deist, and some of our great Founding Fathers were in fact Deists. The full Pledge of Allegience and the expression "In God We Trust" in no way bothers me at all.