The resistance of evil is a social duty. Its strongest expression heretofore has been defensive war against a criminally aggressive offending nation. If resistance is itself an evil, war is the most evil form of that evil. The appearance of the atomic bomb is a sign that a new approach must be found today, that the old way of defensive war will not meet the new problems which have arisen. If man is to end war once and for all and find peace, he must do so both internally and externally. He can do the one by ending the rule of the animal aggressive emotions within himself such as greed, anger, revenge, and hatred, and he can do the other by abandoning the slaying of his fellow creatures, whether human or animal. He may take whatever defensive preparations he pleases, but he must stop short at the point of killing other men. The refusal to slaughter would then evoke powerful spiritual forces, and if enough persons evoke them the end of war would be assured. However it is unlikely that such an idealistic course would appeal to more than a small minority of mankind, so that if the end of war is to be brought about in another way it can only be by the political method of an international policing army operated by a world federation of peoples. Since such a federation does not exist today, its only possibility of coming into existence is through the hard lessons learnt out of the appalling destructiveness of an atomic war. There is no other alternative to such a war than the renunciation of the right to kill.
-- Notebooks Category 6: Emotions and Ethics > Chapter 7: Miscellaneous Ethical Issues > # 26
-- Perspectives > Chapter 6: Emotions and Ethics > # 64