The Treaty of Peace and Friendship Between the United States and the Bey and Subjects of Tripoli of Barbary was approved by the Senate and signed by President John Adams on June 7, 1797. It reads in part as follows:
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.
Sorry, Conservatives, the Senate of the United States and two of our founding fathers, John Adams, who was President at the time and Thomas Jefferson, who was Vice President, agreed with the statement in the treaty that “the Government of the United States of America is not, in any sense, founded on the Christian religion.” Enough said.
Read the treaty here: http://www.stephenjaygould.org/ctrl/treaty_tripoli.html