"It honestly has just astounded me in the last three decades how many good Christian kids have, without a flinch of conscience, marched off to fight in Afghanistan or Iraq or elsewhere. I don’t think they got the memo about what the Sermon on the Mount actually says on things like non-violence, love, forgiveness, non-resistance, loving enemies and the like. Jesus intended for his followers to imitate his own behavior, not that of Caesar and his legions.
If only for the sake of putting the emphasis on the right syllable, Christians ought to be going out of their way to distinguish themselves from their more bellicose neighbors and friends. They ought to be setting a better example of the more excellent way of loving one’s neighbors, even one’s enemies, and I’m pretty sure when Jesus said love your enemies he didn’t mean love them to death at the point of a gun.
For me this means three things at the personal level: 1) I can’t serve in the military, except perhaps as a medic or maybe a chaplain, although I am not even sure that might not be too much of a compromise; 2) it means I must spend my life on positive Gospel tasks, not negative destructive ones. My focus and life style and views must be entirely different from that of perhaps the majority of Americans on these matters; 3) it means that I must support those Jesus says are blessed— the peacemakers."
Ben Witherington III, "The Prince of Peace - Part One"