War and Christianity are not compatible.
War is one of the worst, most terrible things in this world.
War in this world can be stopped not by the ruling establishment, but by those who suffer from the war. They will do the most natural thing: stop obeying orders.
The armed world and the wars it wages will be destroyed one day, but not by the kings or the rulers of this world. War is profitable for them. War will stop the moment the people who suffer from war fully understand that it is evil.