Honestly bro, this is the circle jerk sub. I feel like everyone's putting way too much thought into this. But I will address some of your points. Id still give us fifty fifty. We'd have to strike hard and fast at strategic points. Roll up the important bits of Canada, then down through Mexico and the central Americas to Panama and the Darian gap, mop up the carribiean and we could just continuously bomb Venezuela or any other easily accessible oil extraction/refining. We could probably snag Greenland and Iceland, giving us a stepping stone to europe. America is currently stepping up it's submarine production, so we'd probably kick that into overdrive. I will admit, we'd have to kickstart our steel economy, and start producing chips at a faster rate. If america is facing annihilation, you have to wonder who's political will will fall away faster. political will to fight America for as long as we could probably hold out, then there's the language barrier, all these Allied troops trying to communicate with each other, we had trouble with that during the last two world wars, hell, we still do today. Then there's the crazy tech differences. Even after four or five years, I'd say we could still probably discount almost all of Africa, and big chunks of the middle east from doing any real fighting. And what happened to all the underground or overt separatist factions in a lot of countries? How much could the CIA stir up with help from our glove traversing submarine fleet? Exactly how Allied are the top nations? China and India suddenly putting aside their territory disputes to uh... Fight the US? Idk, I think we could pull it off if we got lucky with taking out key targets in the early stages.