Forget the Canadian military, if the US couldn't defeat the Taliban with NATO help, what hope do they have against Canadians without it?

Canadians aren't even a different skin color - what is the US going to do, stop and question every white person with a gun? Every white person traveling long distances in a car?

Oh hey look now the Rocky Mountains are impassable by land because there are Canadian resistance hidden in caves all the way down to Mexico. But surely the western seaboard and its population will be loyal to Trump, right?

And so it goes. An invasion of Canada would dissolve the USA in a few years.