(I.e., you seem to be stating that Christianity did not convey morality and wisdom to Americans which has been vitally important to our republican government, whether in its foundation, structure, or maintenance.)
I soberly suggest you read more from such political theorists as those most credited by John Adams and Thomas Jefferson, for our republic, including Algernon Sidney and John Locke, instead of the writing of revisionists who spent their impressionable years steeped in Marxism. Also, the writings of the other founders, are preferable to the Koestlers, Rands, etc. of the world. Why not go to the authentic founders our republic, instead of 20th Century Marx-reactionaries? Of those two groups, which were the ones who were there and who actually did it?
Here are citations with links:
Defence of the Constitutions of Government of the United States of America
(An aside in this thread, but very germane to FreeRepublic.com.)