Kind of disagree there. Keeping total separation as I think you are intending it leaves only one sect to run government, which is Atheistic people, also a religion, so now you have no viable people for government under separation fo state because technically any belief or lack there of is an identity to a belief which leaves no one qualified for elections. Having mixed governing prevents a .gov identity (local/state/federal) from swaying from one group to another. Keeps the government from proclaiming you will be Church of England and you'll like it. Free exercise just means I can be CoC, you can be Methodist, Billy Bob can be evangelical, Rico can be Catholic, Demon child can be atheist, yet we can all have a vested and equal interest in how our elected officials govern for the citizenry.