I believe that's the one where we said we are not a Christian nation.
The trend of Muslim defeat began to reverse after the Second World War even though many Muslim leaders had backed Hitler’s Third Reich.
More specifically, the grand mufti of Jerusalem worked closely with Hitler on a solution to their shared "Jewish problem." And today's Palestinians have the gall to play the innocent victim role.
The Treaty of Tripoli never asserted that America was not a Christian nation. Article 11 of The Treaty of Tripoli said that the American government was not founded on the Christian religion. This is a difficult concept to grasp for those who have come to believe otherwise.
What Article 11 is actually reported to have said is:
ARTICLE 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 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.
The Avalon Project at Yale studied the translations in great detail and actually expressed doubts that Article 11 even existed.
Briefly, very briefly, the point was that if the America government was not founded in Christianity then the American Navy personal were not in need of conversion by the Muslims, who were referred to as Musselmen.