In reaching these conclusions the Interim Committee carefully considered such alternatives as a detailed advance warning or a demonstration in some uninhabited area. Both of these suggestions were discarded as impractical. They were not regarded as likely to be effective in compelling a surrender of Japan, and both of them involved serious risks.
Even the New Mexico test would not give final proof that any given bomb was certain to explode when dropped from a plane. Quite apart from the general unfamiliar nature of atomic explosives, there was the whole problem of exploding a bomb at a pre-determined height in the air by a complicated mechanism which could not be tested in the static test of New Mexico.
Nothing would have been more damaging to our effort to obtain surrender than a warning or a demonstration followed by a dud – and this was a real possibility. Furthermore, we had no bombs to waste. It was vital that a sufficient effect be quickly obtained with the few we had.
The ultimate responsibility for the recommendation to the President rested upon me, and I have no desire to veil it. The conclusions of the committee were similar to my own, although I reached mine independently.
I felt that to extract a genuine surrender from the Emperor and his military advisers, they must be administered a tremendous shock which would carry convincing proof of our power to destroy the Empire. Such an effective shock would save many times the number of lives, both American and Japanese, that it would cost.
There was as yet no indication of any weakening in the Japanese determination to fight rather than accept unconditional surrender. If she should persist in her fight to the end, she had still a great military force.
The total strength of the Japanese army was estimated at about 5,000,000 men. These estimates later proved to be in very close agreement with official Japanese figures.
Plans for the defeat of Japan had been prepared without reliance on the atomic bomb. I was informed that such operations might be expected to cost over 1,000,000 casualties to American forces alone. Additional large losses might be expected among our Allies, and, of course, if our campaign were successful and if we could judge by previous experience, enemy casualties would be much larger than our own. …
On July 28 the Premier of Japan, Suzuki, rejected the Potsdam ultimatum by announcing that it was “unworthy of public notice.” In the face of this rejection we could only proceed to demonstrate that the ultimatum had meant exactly what it said when it stated that if the Japanese continued the war, “the full application of our military power, backed by our resolve, will mean the inevitable and complete destruction of the Japanese armed forces and just as inevitably the utter devastation of the Japanese homeland.”
For such a purpose the atomic bomb was an eminently suitable weapon. The New Mexico test occurred while we were at Potsdam, on July 16. It was immediately clear that the power of the bomb measured up to our highest estimates.
Hiroshima was bombed on Aug. 6, and Nagasaki on Aug. 9. These two cities were active working parts of the Japanese war effort. One was an army centre: the other was naval and industrial. We believed that our attacks had struck cities which must certainly be important to the Japanese military leaders, both Army and Navy, and we waited for a result. We waited one day.
After a prolonged Japanese cabinet session in which the deadlock was broken by the Emperor himself, the offer to surrender was made on Aug. 10.
The two atomic bombs which we had dropped were the only ones we had ready, and our rate of production at the time was very small.
The atomic bomb was more than a weapon of terrible destruction; it was a psychological weapon. In March 1945, our Air Force had launched its first great incendiary raid on the Tokyo area. In this raid more damage was done and more casualties were inflicted than was the case at Hiroshima. Hundreds of bombers took part and hundreds of tons of incendiaries were dropped. Similar successive raids burned out a great part of the urban area of Japan, but the Japanese fought on.
On Aug. 6 one B-29 dropped a single atomic bomb on Hiroshima. Three days later a second bomb was dropped on Nagasaki and the war was over.
The bomb thus served exactly the purpose we intended. The peace party was able to take the path of surrender, and the whole weight of the Emperor’s prestige was exerted in favour of peace.
In the light of the alternatives which, on a fair estimate, were open to us I believe that no man, in our position and subject to our responsibilities, holding in his hands a weapon of such possibilities for accomplishing this purpose and avoiding the enormous losses of human life which otherwise confronted us, could have failed to use it and afterwards looked his countrymen in the face.
As I read over what I have written I am aware that much of it, in this year of peace, may have a harsh and unfeeling sound. It would perhaps be possible to say the same things and say them more gently. But I do not think it would be wise. As I look back over the five years of my service as Secretary of War, I see too many stern and heartrending decisions to be willing to pretend that war is anything else than what it is.
In this last great action of the Second World War we were given final proof that war is death. War in the 20th century has grown steadily more barbarous, more destructive, more debased in all its aspects. Now, with the release of atomic energy, man’s ability to destroy himself is very nearly complete.
The bombs dropped on Hiroshima and Nagasaki ended a war. They also made it wholly clear that we must never have another war. This is the lesson men and leaders everywhere must learn, and I believe that when they learn it they will find a way to lasting peace. There is no other choice.