His conclusions are similar to yours. But then, I think anyone cannot argue otherwise unless they want to adopt a position that’s basically nihilism.

Udall named three top military commanders who were totally against using the bomb on civilians these men were convinced Japan was already beaten and they were in a position to know. Gen. Dwight Eisenhower told Secretary of War Stimson Japan was defeated and this feeling was shared by Gen. Douglas McArthur both of these men knew the Japanese were cut off from the raw materials needed to conduct war. Admiral William Leahy felt the use of atomic weapons against Japanese civilians would violate every Christian ethic and all known laws of war. Eisenhower also pointed out that shocking the world with atomic strikes might spark a future arms race but these concerns were brushed aside by civilian decision makers.

On pg 49 in “the Angry Genie: One Mans Walk Through The Nuclear Age” By Karl. Z Morgan (father of Health Physics) he contends Hiroshima was a diplomatic master card in future relations with the Soviet Union and Nagasaki was just a comparative field test of two different weapon designs. The botched bombing of Nagasaki made comparison impossible so another bombing was planned but Truman put a stop to a third bombing against Tokyo on August 10 because the thought of wiping out another 100,000 people was too terrible to contemplate.

Personally I find the idea that the two atom strikes were part “live” test and part demonstration to the Russians in Manchuria is fairly plausible. It is obvious the US looked the other way at the end of the war to acquire Nazi scientist and the gruesome results of Japan’s Unit 731 in Manchuria I don’t think it is too much of a stretch to think they’d see Japan as a valid test subject for atomic strikes. The US had a list of Japanese cities that were spared attack in order to have pristine targets and the ABCC studied the results to set future radiation safety standards. I’d like to see the target list that was spared in Germany. If we had been ready in time I don’t think we would have had moral qualms against A-bombing Germany I just don’t think they presented the same pure targeting opportunity we found in Japan.

As for a lack of understanding about fallout I think we knew more than we officially let on the men who designed the bombs knew full well only a small fraction of the fuel would be consumed and that fraction would create a whole host of daughter products. According to “Day of Trinity” by Lansing Lamont The path of fallout was closely traced after the Trinity test and by three o-clock in the afternoon, the readings on the radiation counters monitored by Alvin Graves and his wife, Elizabeth, observers assigned to the little town of Carrizozo some 40 miles just slightly north of east from the test site, started to climb rapidly. By 4:20 P.M., eleven hours after the explosion, the counters shot off scale and Alvin Graves called Dr. Stafford Warren, the chief medical officer in charge of radiation monitoring. As Lamont put it, the fate of the little town hung in the balance while the scientists and Army officers decided whether or not to evacuate it. Ultimately, they held off, and within an hour the fallout readings had dropped. Lamont reported that these were difficult hours for Dr. Warren and the officer in charge of the entire project, General Leslie R. Groves. “The medical dangers were most immediate of all,” Lamont wrote, “but, in addition, both men knew that the Army was not too eager to pursue too diligently the possibilities of widespread fallout.”

With the Japanese attempting to get the Soviets to mediate with the Allies on their behalf, this was laid out in diplomatic signals the Americans were reading at the time. The Japanese envoy in Moscow was putting forward the idea that retention of the Japanese form of government (not just the Emperor but the system that put the military in charge) as sufficient and this was being rejected by the foreign ministry in its signals giving his instructions and giving no sign such conditions would be sufficient. That was still the case late in July when the decision was being made.

Try Richard Frank’s ‘Downfall’, rather than an editorial, for a thorough debunking of the idea that all that was required was an offer to let the Emperor retain his title. You’ll find no dearth of information there.