I have no idea why this is so difficult a concept for you. I did not focus on American will anyway, but on the will of the British and the Soviets. If they had had a failure of will, the war would have been lost before we entered it.
Of course, the Germans and Japanese had a tremendous "will to fight". However, the Italian front crumbled because the Italians did not, and this helped. In addition, German moral was deteriorating, as is evidenced by the attempts on Hitler's life, and after the Battle of the Bulge, the German's were far readier to surrender. On the Eastern front, the Germans surrendered massively at Stalingrad, despite Hitler's orders to fight to the death. Troops which were in the path of the Soviet Army as the Allies closed in tried to escape to the West to surrender to the Americans and British. Most importantly, there was no attempt to mount a guerrilla war against the occupation, in spite of SS plans to do so.
As for the Japanese, they lost the will to fight after the bombing of Nagasaki. The Emperor capitulated. Although there were a few mutinies among junior officers unwilling to surrender, they were put down, and the Japanese military generally obeyed the Emperor. There was no resistance to the occupation, and cooperation was stunning. |