Canada, as it currently exists, serves a very important function for the US military.
Without Canada, we have no easy option for those who’ve voluntarily signed a military contract, but don’t have the honor, nor integrity, to actually see it through if the situation goes all shooty and stuff.
Without Canada, we’d have to take those sad sacks, malingerers and otherwise degenerates with us when we went to fight.
We just call them DEMOCRATS.