In the past, international aggression accompanied by force had to be met by national defense accompanied by force. The resultant war was, unhappily, inescapable. It was bad, but it was better than surrendering to evil. In the present, this is no longer true. The use of nuclear forces in war is a completely immoral act. It is so not only because the scale on which it annihilates men, women, and children alike is unheard of, but also because the aftermath which succeeds it will be so savage as to be worse than the communism or capitalism such a war sets out to destroy. The means used being wrong, the end result will be equally wrong, besides being unwanted and perhaps unexpected.
-- Notebooks Category 11: The Negatives > Chapter 3: Their Presence in The World > # 450