I too can't see how passing such a resolution wouldn't be direct violation of the separation of church and state.
In fact in the Treaty of Tripoli, authored in 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 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.