When William Penn was struggling with the pacifist teachings of George Fox, he was faced with a dilemma. According to custom, a member of his class of gentlemen was required to carry a sword. He asked Fox what he should do and Fox answered Penn in typical Quaker (or perhaps Zen) fashion. He said, "Carry it for as long as you can."
The problem with a wholly gratuitous God, a completely non-violent God, is that in following a God like that, our own violence will increasingly be exposed and our rational arguments for using any form of violence will become less and less convincing. But what seems to be the crux of the matter for Western Christianity is the notion of "just war" waged by nations as something entirely other than "personal defence". The former is viewed as entirely legitimate, and the latter is seen as illegitimate, at least theoretically, in light of Christ’s counsel to "turn the other cheek". However, even our moral rationale for waging "just" war is becoming harder and harder to justify. I believe this has to do with the permeating effect of the sermon on the mount. If the peace-makers operate and are blessed only within their "personal spheres" the global vision of Jesus makes no sense. The meek inherent their personal space but certainly not the earth.
If it is a duty for nation-states to defend themselves violently, it is not a Christian duty. Although the media blaze of Dr. Charles Stanley’s In Touch ministry will tell you otherwise, war is not divinely sanctioned. Perhaps the impassioned Christianized patriotism embedded in the arguments for justification of the current war belies its indefensible nature.
No, passivism/non-violence is not practical. But it is gospel and it is essential. And it is central to the "Father" who is revealed to us through Jesus. This is just one huge inconvenient truth for followers of Christ. Because again, it means there is no divine sanction for war.
Historians agree that this no-divine-sanction-for-war was understood for 300 years, by pre-Constantinian Christians. As it was, these early Christians were simply "unfit for service". And many of them perished for it. Now that’s a practical problem.
When Penn again met Fox, he was no longer wearing his sword. Penn then said, "I have taken your advice; I wore it as long as I could."