Past indications that Canada would defend their north have come to nothing:
Canada needs to stop pretending that it cares about the North. but it could extend their control in the Arctic at the expense of Canada. Decades of false rhetoric has created expectations among those few who do live up North that someone “has their back.” No one does. They’re on their own and they have been for generations. We tell the world the North is ours, that we are protecting our sovereignty and our vast mineral wealth. But the truth is we aren’t, and those resources are so far from the nearest railhead they may as well be on the moon.
Russia isn't going to reach Hudson Bay, but it could extend their control of the Arctic at Canada's expense. Talk about a "frozen conflict," eh?
I once thought that we could afford to shift NATO's focus to the north, so that NATO's Arctic states were the front line rather than the flank and rear area. But Russian aggression in the east is compelling NATO to keep the east as the main front line.
But while Canada may still be the rear area for the eastern front, for Canada the north could be their front line in the face of Russia's renewed focus on the Arctic where Canada is thin on the ground (and sea and air).
And I still think we could use a Polar Command. Forces that can fight and survive in that environment don't need to be large (and can't be because of logistics challenges) but they do need specialized training and equipment to do more than die of exposure after being sent north.