"As the Government of the United States...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." [Emphasis mine]
The treaty containing this phrase was ratified unanimously by the senate and published in Philadelphia and New York without comment. From this historians and polemicists have argued that a clear separation between church and state was not only accepted by the American government but by the American public.
Marc Comtois over at Spinning Clio has done a close analysis of the aforementioned treaty and the context in which it was produced and concludes that it is a flimsy foundation upon which to insist, as the secularists have done, that the US government specifically embraced a separation of church and state. He concludes:
to make what was essentially a throwaway line of questionable provenance contained within the 11th section of a relatively obscure treaty a key pillar in the argument that Christianity was disavowed as informing the founding of the U.S is more rhetoric than history.Read Marc's comments here.