I think Scalia is saying that if you want to get rid of "God" in the government, don't try to do it under the guise of a "Separation of Church and State" clause (since there is no such clause) - do it the way the system allows you to do it - at the ballot box.
Scalia would say, "If you want to prevent Christmas Displays on your town square, don't dis-allow it on Constitutional Grounds - pass a law that prevents it by reason of democratic decree.
my humble opinion as a constitutional legal layman