The greatest passion is not driven necessarily by religion. Rather it is driven when assumptions about a way of life are challenged. The American Civil War was driven by assumptions and passions about the equality of man and a way of life. World Wars were driven by different assumptions about the future path of mankind. Likewise, the U.S./Soviet Cold War was driven by different assumptions about the path of history and the direction that path would take.
This type of conflict has two paths of being reconciled. In the first path, a great and horrific war must be fought to complete conclusion. In the second, dividing lines must be set. Then, time will resolve the path of history.