JudgeMental said:
the trolley car dilemma.
That it was. And one that weighed heavily on Truman, who was unaware of the bomb’s existence until he took over as President after Roosevelt died.
Conservative estimates of Allied dead from the invasion of the Japanese home islands (Operation Downfall) were 500,000, with 1 million wounded. Other estimates provided figures anywhere from two to four times as many.
Operation Olympic, the unavoidable first-up invasion of Kyushu would have seen Allied assault waves opposed by 350,000 dug-in and determined Japanese troops (who knew precisely where the attack would come), supported by 1,000 kamikaze planes. The slaughter would have been horrendous on both sides.
Amongst their other concerns, the Americans had severe doubts that they could even produce enough Purple Heart medals (for Americans killed or wounded in service) fast enough to meet the expected numbers needed.
The Japanese Imperial General Staff had accepted the concept that if 20 million Japanese dead was the price of ‘national honour’, then so be it. Every citizen was to be conscripted into the fighting: old men and women, young boys and girls, armed with hand grenades or even just a sharpened bamboo stake, driven in waves into the Allied guns.
Conservative estimates of Japanese who would be killed in the fighting to subdue the home islands were from 3 million to 5 million.
An argument is made that the Japanese islands could have been blockaded, and starved into submission. Perhaps that was possible. But they really would have been starved into surrendering, with millions of people dying a slow and awful death, with the young, the old, and the frail the first to die.
Given these prospects, and given an opportunity to demonstrate an unanswerable capability and its actual effects on a comparatively small target, what choice did Truman have?