One thing that hasn't been mentioned and needs to be mentioned, because it's a decision that will need to be made by this government in all likelihood, is how Canada's new Canadian surface combatants will be equipped. There will be a push from the navy to make them Aegis class and to have the radar and the standard missile-3s that would enable them to provide missile defence capabilities, as the Norwegians are evidently planning to do.
That's a big ask that you'll get from the navy. Having that Aegis-class capability on a surface combatant will probably add somewhere in the range of half a billion dollars to the cost of that single vessel. This is a big one. It's coming.
How you think about missile defence in the North American context will necessarily bleed into that later debate.