The fundamental evil is not nuclear weapons but rather the concept of waging war by attacking the enemy's civilian population. Civilians always suffer in wartime, because they provide invaders with opportunities of revenge, booty and indulgence in the pleasures of otherwise punishable offenses.
By the beginning of the World War I, nations regarding themselves as civilized generally avoided attacking the civilian population of enemy nations also considered to be civilized. Germany apparently was the first to violate this principle, executing Belgian irregulars defending their homes, instituting Zeppelin raids on London, and firing the huge "Big Bertha" cannon into Paris.
Still, such transgressions were relatively isolated and didn't represent a calculated strategy. This less civilized kind of thinking was introduced during World War II by the exponents of "victory through air power," a policy adopted by all the major belligerents.
Marvin A. Moss