Originally Posted by Stormvanger
I think it would have been an ugly land war. But if it had gone on long enough, the US would have gained a lot of territory in Canada once the Nazis began acting up. Britain would be overextended and probably end the war in north america with a treaty that involved the US keeping some or much of the land it gained. But THAT in turn would have delayed or prevented the US entry into WW2 as we would have recent hatred working AGAINST the notion of helping Britain out.
Hard to say what happens after that. WW2 ending in a treaty with Nazi Germany instead of their total defeat?
Had America attacked Canada, what's the chances that Britain would even give two shits about Hitler? It's common knowledge that Hitler never wanted to go to war with Britain and her Empire.
As for the land gains, yes you would have gained huge amounts of land but Canada is not a push over and would have countered with their defensive plans. At the same time Britain would reinforce Canada with her own troops.
Remember that by the end of year in 1930, the USN was about 140~ ships big. The Royal Navy was some 600/700 ships in size. Nothing to stop us blockading US Ports and shelling your coastal cities.