Apparently, most Republicans and Tea Party members are not familiar with the Treaty with Tripoli signed in November 1796. Here is Article 11 of that treaty unanimously approved by Congress and signed by President John Adams.
• Art. 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 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.