Unlike most governments of the past, the American Founding Fathers set up a government divorced from any religion. Their establishment of a secular government did not require a reflection to themselves of its origin; they knew this as a ubiquitous unspoken given. However, as the United States delved into international affairs, few foreign nations knew about the intentions of the U.S. For this reason, an insight from at a little known but legal document written in the late 1700s explicitly reveals the secular nature of the U.S. goverenment to a foreign nation. Officially called the "Treaty of peace and friendship between the United States of America and the Bey and Subjects of Tripoli, of Barbary," most refer to it as simply the Treaty of Tripoli. In Article 11, it states:
"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 Musselmen; and as the said States never have entered into any war or act of hostility against any Mehomitan 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."
The preliminary treaty began with a signing on 4 November, 1796 (the end of George Washington's last term as president). Joel Barlow, the American diplomat served as counsel to Algiers and held responsibility for the treaty negotiations. Barlow had once served under Washington as a chaplain in the revolutionary army. He became good friends with Paine, Jefferson, and read Enlightenment literature. Later he abandoned Christian orthodoxy for rationalism and became an advocate of secular government. Joel Barlow wrote the original English version of the treaty, including Amendment 11. Barlow forwarded the treaty to U.S. legislators for approval in 1797. Timothy Pickering, the secretary of state, endorsed it and John Adams concurred (now during his presidency), sending the document on to the Senate. The Senate approved the treaty on June 7, 1797, and officially ratified by the Senate with John Adams signature on 10 June, 1797. All during this multi-review process, the wording of Article 11 never raised the slightest concern. The treaty even became public through its publication in The Philadelphia Gazette on 17 June 1797.
So here we have a clear admission by the United States in 1797 that our government did not found itself upon Christianity. Unlike the Declaration of Independence, this treaty represented U.S. law as all U.S. Treaties do (see the Constitution, Article VI, Sect.2: "This Constitution, and the laws of the United States which shall be made in pursuance thereof, and all treaties made, or which shall be made, under the authority of the United States, shall be the supreme law of the land; and the judges in every State shall be bound thereby, anything in the constitution or laws of any State to the contrary notwithstanding.")
http://www.nobeliefs.com/Tripoli.htm