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 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.