After all the discussion on the Founding Fathers and their position towards religion, I thought this to be interesting.
This treaty was initiated by George Washington, was finally completed by John Adams and then ratified by Congress in 1797.
This article of the treaty is the interesting one regarding Founding Fathers take on our "Christian Nation":
Art. 11. As the Government of the United States of America is not, in any sense, founded on the Christian religion; as it has in itself no character of enmity against the laws, religion, or tranquillity, of Mussulmen; and, as the said States never entered into any war, or act of hostility against any Mahometan nation, it is declared by the parties, that no pretext arising from religious opinions, shall ever produce an interruption of the harmony existing between the two countries.