Okay so the deal is this: I have a timeline centred around The Second Great War, roughly from 1942-1948 or 1940-1948. POD is in The Great War, which Germany won through Spring Offensive in 1918 and America never participated in. This led to decent German-American relations, maintained British-Japanese alliance, much worse British-American relations, and somewhat militarily weaker US. Pearl Harbour will happen, as OTL, though the time may change. America's buddy Germany is either in a war or at odds with fascist Novaroma pact, and Churchill (not in power but still important) is close with its leader Charles de Gaulle. Well, no doubt America will attack Japan, but would this give enough reason for them to enact War Plan Red and take on Canada, bringing Britain into the war?
And as a followup, does Canada stand a chance to hold USA off long enough for Commonwealth to support them? I find the IOTL Canadian plan of flanking American formations and attacking straight into big cities and then retreating to cause chaos and disrupt American strategy... intriguing.
As a second followup, if this is completely ASB territory, is there any other way to open up an American front?