That wasn’t what you asked me. You asked how utilitarianism would cope with such a dilemma. I never claimed utilitarianism was used to make the decision. It probably wasn’t.
Sometimes tough decisions have to be made. We can ignore them because they make us uncomfortable. We can call the brave people who grapple with those decisions cold-hearted. The decisions have to be made regardless. Who knows what the world would be like now had the Nazis won the war because we were hesitant to defend ourselves against Japan? How many others would have been slaughtered?
I disagree that a twisted form of Utlilitarianism probably wasn’t used to drop the bombs on Japan. Instead of the War department seeking to achieve the greatest happiness for the greatest number, what they really sought was the greatest misery for the greatest number, and the greatest number of civilians at that.
Robert Oppenheimer, who had been the director of the Manhattan Project that created the first atomic bombs, by the 1960s had come to terms with a late blooming conscience about the whole affair. Since Hiroshima and Nagasaki greater bombs had been invented, and Russia was also building them. He said at a public seminar:
“I find myself profoundly in anguish over the fact that no ethical discussion of any weight or nobility had been addressed to the problem of atomic weapons… What are we to make of a civilization which has always regarded ethics an essential part of human life, and which has always had in it an articulate, deep, fervent conviction, never perhaps held by the majority, but never absent: adedication to Ahimsa, the Sanskrit word that means doing no harm or hurt, which you find in Jesus and simply and clearly in Socrates; what are we to think of a civilization which has not been able to talk about the prospect of killing almost everybody, except in prudential and game-theoretic terms?”
This is clearly an indictment of the Utilitarian motive for bombing Hiroshima and Nagasaki.
What do you expect will be the moral axiom of the people who might be planning to nuke New York City and Washington, D.C. … the financial, political, and military capitols of North America? Do you expect it will be “Do unto others as you would have them do unto you” (friendship and justice) … or do you expect it will be, “Let’s maximize our happiness by killing as many Americans as we can”?