This statement was made by an official representative of the U.S. during Washington's presidency, but is actually a line from the English version of the Treaty of Tripoli ( Article 11 http://avalon.law.yale.edu/18th_century/bar1796t.asp#art11), which was signed at Tripoli on November 4, 1796, and at Algiers on January 3, 1797. It received ratification unanimously from the U.S. Senate on June 7, 1797 and was signed into law by John Adams. The wording of the treaty is by Joel Barlow, U.S. Consul, who had served as Washington's chaplain, and was also a good friend of Paine and Jefferson; Article 11 of it reads:
::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 or enmity against the laws, religion or tranquility 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.
Misattributed
