Nearly all wars in known history have had some aspect of religion/faith in the Casus Belli. Granted, in the earlier wars, both "sides" believed in God, but disagreed in What God Wanted. Some thought "Their God" would give them unlimited power, if they won the war, it was "proof" for them.
This is exactly what happens when the spiritual aspect of religion is suppressed by selfish individuals. International terrorism is proof of this!
Spiritualism is the cream of any religion.