What remains of Canada could, if they liked, further prostitute themselves and permit US enemies to establish bases in Canada. Canadians can formalize the moral capitulation they have already made and of which continue to boast to finally cash in on the open contempt they have for their generous and benign US neighbors. It would not be smart, but they could do that. In fact, I am surprised that Mexico has not yet done this, AGAIN..... (because remember, Mexico invited the French to help them with their previous territorial aspirations in N. America.)
When? You talking about the French conquest of Mexico during the WBTS? Most Mexicans fought the French and their collaborators.
There were Mexicans who talked to the Germans during WWI about help in the reconquista of the American SW.