What was the Cause for Surrender

One of the interesting aspects, to me at least, of the bombings is the debate over how necessary they were. In the perfect clarity of hindsight many look back at it and say how Japan was on the brink of surrender. The real question of morality of the bombings is not what we know now; it is what was known at the time. A moral issue cannot make assumptions about an action based on comprehensive knowledge gained by reviewing every fact from the distance of a historian. It needs to be examined on the basis of what the involved parties knew at the time. The decision would only be morally invalidated if the information at the time invalidated it.

There are those who would argue Soviet intervention was at least as significant of a factor if not more. The argument goes that from the timing and vagueness of comments in personal journals and official communications it could be seen that the Soviet invasion of Manchuria was at least as important a factor, if not more so. The Japanese had been trying to get the Soviet Union to be an arbitrator for them according to some historians according to Tsuyoshi Hasegawa.  Hasegawa argues that “of the two factors—the atomic bombing of Hiroshima and Soviet entry into the war—the Soviet invasion had a more important effect on Japan’s decision to surrender.” And he has some evidence to back this up. There is much room here for interpretation of the facts.

Japanese representative General Yoshijiro signs the instrument of unconditional surrender on the U.S.S. Missouri, as General Douglas MacArthur watches. Credit: Harry S. Truman Library & Museum.

Truman had a number of advisers and a great deal of military information to go by, so to determine how good a decision it was we need to look at what he did with the information he had. Winston Churchill supported the decision with the argument “[t]here are voices which assert that the bomb should never have been used at all. I cannot associate myself with such ideas. ... I am surprised that very worthy people—but people who in most cases had no intention of proceeding to the Japanese front themselves—should adopt the position that rather than throw this bomb, we should have sacrificed a million American and a quarter of a million British lives.” Mr. Churchill’s opinion is sharply worded but the point of it is a good one, it is easy to criticize when you would not have been on the wrong end of the gun. Likewise the Potsdam Declaration of 1945 called for  “ the government of Japan to proclaim now the unconditional surrender of all Japanese armed forces, and to provide proper and adequate assurances of their good faith in such action. The alternative for Japan is prompt and utter destruction.” It could be said that this foreshadowed the horror of the bombings to come.


One of the primary sources of support for the bombings was the massive casualty estimates that were being put forth. There were a number of differing estimates, but all of them were immense. Another was magic, or rather Magic, the clever name for the code breakers who were listening in on what Japan was planning. Magic gave the US and the Allies insight on how some Japanese envoys who wanted peace with the US. This is a point that many who argue against the bombings would say negates the need for them except for one thing, none of these overtures were from people with any true authority. These were all unsanctioned and sadly also they were in the minority of intercepts, as most were indicative of support for continuing the war. In fact military intercepts from Magic indicated that an examination of Allied tactics had shown the Japanese exactly where Operation Downfall would have landed its initial phase, Operation Olympic. The other important information from this is that there was a massive troop build-up in the area and a strong counter-plan a strategy they called Ketsu Go. Ketsu Go or Operation Decisive they felt would allow the military to end the war in a way favorable to Imperial Japan.