Atomic Bombs and Audiences

LFC points to an article by Ward Wilson suggesting that the Japanese did not surrender in WWII because of the bombs dropped on Hiroshima and Nagasaki, but because the USSR dropped its neutrality with Japan. This argument presumes that the USSR's policy change was independent of the US's decision to drop the bombs, and the US's decision to drop the bombs when it did was independent of any consideration other than motivating Japanese surrender. Given what was going on in Europe (and China) at the time this seems exceptionally unlikely. Stalin had bigger fish to fry than securing marginally better terms of surrender for the Japanese Emperor, and he had agreed at Yalta to declare war on Japan within three months. The US had already conceded half of Europe but was determined to keep the USSR out of Asia. Given the rapidly-expanding US/USSR rivalry and the US's technological advantage it was in Stalin's interest to mollify the US at least until the USSR could also develop atomic weaponry.

I.e., just move the question back a step: why did the USSR pick precisely that moment to revisit their position as a potential intermediary between the US and Japan? There are two candidates. First is the Yalta agreement. Second is the deployment of the atomic bombs. Here the timing of the US dropping the bombs becomes important. The US could have dropped the bomb at any time from July 15th forward. August 8th was the deadline for the Soviets to enter the Pacific theater per the Yalta agreement. Hiroshima was August 6th. The USSR entered on August 8th by invading Manchuria (it was still the 7th in Moscow, but the time difference meant it was the 8th in Tokyo). Nagasaki was August 9th.

There is quite a lot of evidence that Stalin did not recognize the significance of atomic weaponry until it was used, and some good reasons to think that the bombs were in fact dropped primarily for the benefit of Soviet audiences, not Japanese. Stalin believed this anyway. The bombs -- or at least the second one -- were probably dropped to keep the Soviets out of E. Asia. There is no other good explanation for why the first bomb was dropped just before the deadline for Soviet intervention on the terms agreed at Yalta, or for why the second bomb was dropped at all.

From hindsight this makes the use of atomic weapons less justifiable on strategic as well as moral grounds. The Soviets obviously took from this experience that the Americans were quite dangerous and were in fact imperial. The dropping of the bombs hardened Stalin and perhaps made the Cold War more dangerous than it needed to be. This was made clear by the Bolshoi speech in 1946. Whether or not the bombings had any deterrent effect from 1945-1949 (the period before the USSR successfully detonated a bomb) is difficult to discern, but once the Soviets had achieved nuclear parity (or close enough to it) competitive brinksmanship was probably inevitable. It may have been anyway, but the U.S. took the first step by bombing Hiroshima and Nagasaki. Any other possible paths of history were cut off at that moment.

Another example of why we should be wary of Ceteris Paribus Theories of International Relations.