Silly thread. Belief in God, rejection of God, is up to the individual. It has always been, and this was held dearly by our founders. "One nation, under God" was a later concept introduced by religious statists like Francis Bellamy.
Besides there are plenty of individuals around that embrace God, evangelicals and the like, and they are plenty loud. I hear them all the time.
We are not one nation under God. We are one nation. We're supposed to respect one another's freedom, including of the religious ilk. Our collective fate is not wrapped up in a collective belief. It never has. Sometimes it has been wrapped up in a collective effort (economic booms, WWII, etc.), but collective beliefs? Never. If you want collective belief, I suggest socialism.