On Aug. 6, the American bomber Enola Gay dropped its payload on Hiroshima, leaving the signature mushroom cloud and devastation on the ground, including something on the order of 100,000 killed. (The figures remain disputed, and depend on how the fatalities are counted.)
As Hasegawa writes in his book “Racing the Enemy,” the Japanese leadership reacted with concern, but not panic. On Aug. 7, Foreign Minister Shigenori Togo sent an urgent coded telegram to his ambassador in Moscow, asking him to press for a response to the Japanese request for mediation, which the Soviets had yet to provide. The bombing added a “sense of urgency,” Hasegawa says, but the plan remained the same.
Very late the next night, however, something happened that did change the plan. The Soviet Union declared war and launched a broad surprise attack on Japanese forces in Manchuria. In that instant, Japan’s strategy was ruined. Stalin would not be extracting concessions from the Americans. And the approaching Red Army brought new concerns: The military position was more dire, and it was hard to imagine occupying communists allowing Japan’s traditional imperial system to continue. Better to surrender to Washington than to Moscow.
I don't know anything about this subject. It sounds plausible, I guess. I'll buy it for the sake of the deterrence part of the argument:
What happened at Hiroshima and Nagasaki has framed the world’s thinking about nuclear weapons. Those days in August remain the only instance of nuclear war. The sheer horrors of the destruction, and the lingering poison of radioactivity, inform what has come to be called nuclear deterrence: No sane nation would bring a nuclear attack on itself, and so having nuclear weapons deters your enemies from attacking. When two rival nations have nuclear weapons, as during the Cold War, the result is stalemate.
Hasegawa’s scholarship disturbs this simple logic. If the atomic bomb alone could not compel the Japanese to submit, then perhaps the nuclear deterrent is not as strong as it seems. In fact, Wilson argues, history suggests that leveling population centers, by whatever method, does not force surrender. The Allied firebombing of Dresden in February of 1945 killed many people, but the Germans did not capitulate. The long-range German bombing of London did not push Churchill towards acquiescence. And it is nearly impossible to imagine that a bomb detonated on American soil, even one that immolated a large city, would prompt the nation to bow in surrender.
If killing large numbers of civilians does not have a military impact, then what, Wilson asks, is the purpose of keeping nuclear weapons? We know they are dangerous. If they turn out not to be strategically effective, then nuclear weapons are not trump cards, but time bombs beneath our feet.
I don't think this is a strong argument against our conception of nuclear deterrence. Its true that the damage that would be caused by a nuclear attack is one of the main driving forces behind deterrence. But the situation with the US and Japan is different that the situations states face today.
At the end of WWII, the US was the only nuclear power in the world. Japan didn't have any nuclear weapons. They could barely strike the US with conventional bombs, not withstanding Pearl Harbor which was much closer to Japan than the US mainland. So Japan didn't really have much of a deterrent to the US bombing them. And that is the other key aspect of modern nuclear deterrence, as it was during the Cold War.
During the Cold War, the US as the Soviet Union had massive amounts of nuclear weapons and large countries within which they could spread out and hide their stockpiles. That meant the two key factors for deterrence were present, massive destructive ability and the inability to destroy the other's stockpile in order to ensure no retaliation. If the US initiated a nuclear attack on Russia it was assumed that Russia would retaliate with a nuclear attack of their own. There would be no way on the part of the US to be sure that in their initial strike they would destroy all of the Soviets' weapons. So the US would essentially be guaranteeing some sort of massive destruction of its own country if it attacked the Soviets.
The same logic holds today with countries like Pakistan and India and any other nuclear power. The reason the logic doesn't hold with Japan during WWII is because they didn't have nuclear weapons of their own. If they did, the US would have needed to account for the possibility that Japan could drop one of their bombs on the US if we weren't able to destroy it in our attack on Japan. Truman's decision would have been different. Instead of just the moral question of whether he was willing to kill thousands of Japanese civilians, he would have also had to ask himself whether he was willing to risk the lives of thousands of US civilians. Because he didn't have take that into account he was more willing to use nuclear weapons.
Another thing that Truman didn't have to worry about that states have to take into account today is alliances between nuclear powers and non nuclear powers. Canada and Mexico don't have nuclear weapons. But no other nuclear power is seriously considering bombing them. They know that since the US is their ally we will retaliate in some manner, possibly with our nuclear weapons. As I said, no one else had nuclear weapons during WWII. So Truman didn't have to worry about Germany or Russia retaliating against us on the part of Japan.
If this theory were true, it would show the dangers of a ruthless regime that didn't care about the well being of its citizens. Not that people already don't ask similar questions regarding some regimes today. But it would provide data regarding the issue rather than speculation based on what we think are crazy leaders, such as Kim Jong Il or Mahmoud Ahmadinejad. But I don't think it would change our conception of deterrence. Nuclear powers continue to not use their stockpiles. I don't mean to sound completely like a realist because there are other factors at work other than strategic power issues. But as far as deterrence goes, realist theory sill explains a lot