We had the A-bomb in 1945 -- they didn't for years -- case closed.
We had TWO bombs and used them against the nation still fighting us. There is no case much less a "closed" one.
Apparently you also have no idea as to how much destruction the Soviet Union suffered and STILL beat the Nazis. Other forces against Hitler were secondary in importance as any comppetent history of the War shows. It had two main theatres the US vs Japan and Germany vs the USSR.