This one is so convoluted under the surface you can miss things twice. Even on the third time through I was figuring out subplots. Good casting, acting, story and script.
And from a military sense, this could have happened. The Japanese Navy could have pushed through at Pearl Harbor, won Coral Sea and Midway, and we would have sued for peace. Two years earlier, the Axis could have won the battle of Britain, then waited an extra year to concour Russia. They decide to build atomic weapons early and we don't. It was possible if they made no mistakes and we made a bunch.