The concept "separation of Church and State" is in no U.S. document of government. It is a creation in the 20th century, from a phrase Jefferson wrote in a personal letter.
It is NOT in any of Jefferson's books. But technically, it is in one of his writings. It is one phrase by Jefferson, not something he repeatedly or strenuously argued for.
But in any case, the role of Christianity in forming the principles of American democracy is clear.
And equally clear, the desire of its creators that Christian principles would continue to be an enduring part of that democracy, as long as American democracy continues to exist.
Again, I consider Christian concepts to be vastly different from those of Islam.
The ideas of a personal God (-vs- an unknowable God in Islam), of free will (-vs- a more fatalist mindset of Islam), and other ideas of human rights and dignity. That arguably have largely not reached the Islamic world even 200 years after the birth of democracy in the U.S. and Europe.
Article 11 of
The Treaty of Tripoli (1796)
Article 11 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 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."
