We must begin by acknowledging a hard truth. We will not eradicate violent conflict in our lifetimes. There will be times when nations, acting individually or in concert, will find the use of force not only necessary but morally justified.
We are adapted to infinity. We are hard to please, and love nothing which ends: and in nature is no end; but every thing, at the end of one use, is lifted into a superior, and the ascent of these things climbs into daemonic and celestial natures.
The main thing is this: we should never blame anyone or anything for our defeats. No matter how evil their intentions may be, they are altogether unable to harm us until we begin to blame them and use them as excuses for our own unbelief.
We should never forget that God granted us the power to reason so that we would do His work here on Earth - so that we would use science to cure disease, and heal the sick, and save lives.