So in your timeline, the USA is on the defensive back in NA? Ill probably use that too. What about Hawaii?
So far Ive decided that once the British Empire was in collapse, Canada and Newfoundland would become closer to the USA for defensive reasons, and the Newfoundland referendums would have included an American option. The USA and Canada would form an American Union, basically giving the USA controll over Canada, but not exactly annexation. The USA would build a massive Pacific defense force to ward off future attacks from Japan and build up its navy to defend against Germany's massive armada to the east. Presumably the USA and Japan would also develope nukes and an alternate "Cold War" would ensue.
It is considering its massive navy, devoted soldiers, and dominance over East Asia and Oceania. In my timeline neither America nor Japan has developed nuclear weapons before the end of WWII. Its not until a lil while after that the USA and Japan get nukes.
I just want to point out that at the beginning of WWII America's defenses in the west could not have effectively thwarted a Japanese invasion, and during the war they proposed setting up a Pacific defense system that stretched from Alaska, through British Columbia, down to California.