No , Russia was already planning on joining against Japan , this was agreed at both Yalta and Potsdam . Planning , yes . But they didn ' t actually do it until August of 1945 . The nukes were launched first and foremost to end the war quickly . The US government concluded that Japan would hold out until December with the blockade and conventional bombings . Truman was unwilling to wait that long , morale was dangerously low at home and among troops . The possibility of a Soviet invasion was not the main reason . The Russians lacked the capacity to effectively invade Japan , as their struggles in Sakhalin and the Kurils proved . Also , Hokkaido was a defender ' s wet dream just look at the terrain . Even a wildly successful Russian invasion would not have gotten past Hokkaido , which accounts for a tiny portion of Japan ' s population and resources despite a significant portion of its land , so your bankers argument holds no water . And the idea that the Japanese refused to surrender out of fear for the Emperor ' s life is another popular myth . The military leaders wanted to retain Japan ' s sovereignty and military , something that the Allies refused to allow . Even ater the second bomb was dropped , the military and civilian leaders were deadlocked and the Emperor himself had to break the tie . And the issue with Japan was never exploitation rights . In fact , the deal that the US government struck with the nrw Japanese civilian government was that American msrkets would be open to Japan and not the other way around in exchange for Japan allowing the US to station its forces there . Look up the Yoshida Doctrine .