"I gave careful thought to what my advisors had counseled. I wanted to weigh all the possibilities and implications... General Marshall said in Potsdam that if the bomb worked we would save a quarter of a million American lives and probably save millions of Japanese... I did not like the weapon... but I had no qualms if in the long run millions of lives could be saved."
January 1, 1970
https://en.wikiquote.org/wiki/Atomic_bombings_of_Hiroshima_and_Nagasaki