In 1823, U.S. "founding father" James Madison wrote:
He was right then and he is right now. When a religion tries to become the state, it not only becomes oppressive to individuals who do not share its rules -- it also betrays its own best values and practitioners.
I'm radical enough to believe that Christianity (the religion of the Jesus movement of which I'm an adherent) has been in trouble ever since it lined up the Emperor Constantine in 325. Being a Christian became a necessity for political advancement in the late Roman empire and the rest is history.
Pretty soon Europe had a empire that was "neither holy, nor Roman, nor an empire" but it sure had plenty of religious wars, especially when national aspirations teamed up with a new Protestant theology to challenge the rule of the pope. Sometimes, as in England, various brands of Protestantism fought it out for control of the state.
Madison and the U.S. founders may have held some religious beliefs (though one can wonder whether some of their evocations of the deity might not have been just necessary spin for their less skeptical fellow citizens), but they came from a tradition that saw religious government as a recipe for war.
These things don't change much, do they?
In the contemporary era of globalization, any faith that cannot live side by side with radically different belief systems, or no belief system, is a recipe for war and violence. And, I would add for myself, a religious faith that leads to war and violence dishonors the very possibility of God's existence.