Originally posted by Engine
No, it was because of great Soviet Red Army, Comrade! Not even puny capitalist atomics scare glorious Red Army!
sigh
According to American attack plans from the 50s - Soviet Army could capture all continental Europe, Middle East and Mediterranian coast regardless to American nuclear weapons. Plans included burning Soviet population centers killing at least 10 million people in a first week. Soviet goals could be reached in no more then six months since hostilities began.
Think about it. Plain artillery and bayonets, no nukes.
I am happy it never happened.
As for Japan - again, Hirohito mentioned Soviet "interference" in Manchuria as a main reason for surrender, not the Bomb.