Presuming a Central Powers victory *after* the USA joins the war. (Paris falls, the French surrender, etc), would the Germans be in a condition to get anything other than peace from the UK/US?
With US Support, it appears that the UK can survive indefinitely in terms of food imports, so I'm not sure what the Germans can do to force anything...
With US Support, it appears that the UK can survive indefinitely in terms of food imports, so I'm not sure what the Germans can do to force anything...