... war production/logistics and manpower US alone had over twice the war making potential of Japan and Germany combined USSR too big to defeat in a total war USSR population alone much greater the Germany's Grim Economic Realities
Hitler surrounded himself with 'yes' men and kept the military decisions to himself. For instance instead of remanning the Units that had suffered big losses Hitler just kept on creating new divisions. I read that on map Hitler had ten million men towards the end of war in the German manned area which was far from truth.
Against both yes, but it was Hitler WHO declared the war to the USA in Dec 1941. Without the Allied supplies starting then we cannot be sure as Stalin cried all possible help from the West.