Authority of the Government comes from the people.

Brad DeLong’s Semi-Daily Journal: Nino Scalia, by Grace of God Justice and Lord
We the People of the United States, in Order to form a more perfect Union, establish Justice, insure domestic Tranquility, provide for the common defence, promote the general Welfare, and secure the Blessings of Liberty to ourselves and our Posterity, do ordain and establish this Constitution for the United States of America.
Read Brad’s entry on Justice Scalia, and his telling comments to the contrary. Unamerican, to begin with. I am not getting into the argument about the seperation of church and state, this is more fundamental.
America is a secular country, founded as a secular country. The fact that many people are religious or call themselves religious is beside the point and does not change the fact that this is a secular country.
Heinlein’s If this Goes On becomes less and less implausible. I still think its 10-1 odds against the country ever going down that road completely, but a decade ago, i’d have made 100-1 odds.