It seems that a critical industry is merely one that has regional political implications like aerospace (Quebec) and energy (Alberta mainly). Given that, the issue is merely political: should Quebec and Alberta have an equal role in our response to economic aggression? And the answer to that is whether Quebec and Alberta wish to be part of Canada. If Alberta wishes to be the 51st state, good riddance and they're welcome to school shootings and healthcare bankruptcies. If Quebec wishes independence, I'm sure we can figure out a method of co-existence. But if they wish to be part of Canada, we must ensure that politics stops at the border and all of us pull together. Hit the US where it hurts most.