This excellent article (of which the clip is merely a teaser) spells out in a logical and reasonable fashion what is so wrong about the inclusion of a religious motif in the command structure of the military.

It sounds like a reenactment of our forefathers. They too laced their speeches and writings with religious embellishments.

To act as Rumsfeld did gives a clear implication that religious authority trumps civil authority. What would happen if some soldiers decided to take orders from a preacher instead of their commanding officers? Could there be a putsch from the pulpit?