I was reading this tumblr post which argues - somewhat compellingly, from my amateur perspective - that the bombing of Hiroshima and Nagasaki served essentially no role in forcing/expediting Japan's surrender at the end of World War II, but instead served to preempt Soviet expansion in East Asia.

I've also heard the argument that what forced Japan's surrender was less the atomic bombings than the pending involvement of the Soviet Union in war against Japan. Was the Soviet invasion of Manchuria enough to force Japan to surrender on its own? Or was the Japanese leadership willing to (and the Japanese economy/population able to ) continue the war and defend the home islands in the absence of the atomic bombings?