Some quotes I found by some of the early leaders of the United States...
- God is an essence we know nothing of. Until this blasphemy is got rid of there will never be any liberal science in the world. --John Adams
- The clergy...believe that any portion of power confided to me [as President] will be exerted in opposition to their schemes. And they believe rightly: for I have sworn upon the altar of god, eternal hostility against every form of tyranny over the mind of man. But this is all they have to fear from me: and enough, too, in their opinion. --Thomas Jefferson to Benjamin Rush, 1800. ME 10:173
- I have seldom met an intelligent person whose views were not narrowed and distorted by religion. -- James Buchanan
- My earlier views at the unsoundness of the Christian scheme of salvation and the human origin of the scriptures, have become clearer and stronger with advancing years and I see no reason for thinking I shall ever change them -- Abraham Lincoln
There is also the story that Washington went to church but left before communion. When the priest confronted him on this matter stating that it was a "bad example," Washington agreed that it was and instead didn't go to church at all.
Realize that this is not to say that religion is wrong, but rather that the forcing of religion upon others through legislating morality or teaching it as part of the public curriculum is ultimately detrimental and contrary to the philosophy of the founders of the United States.