canada does have a substantive task, here.
it needs to convince the united states that it benefits from an open trade agreement more than it benefits from a shift towards autarky.
there are benefits to canada from walking away from nafta in the sense of abandoning the non-trade aspects of the deal. most of the criticism of nafta had to do with the rights it gave to american investors to block sovereign canadian decisions. nafta has prevented us from doing a lot of the nation building projects we wanted to do, and it might have in the end cancelled a lot of these projects carney is pointing towards because it blocks government subsidies. nafta might cancel that pipeline through bc, if somebody wants to use it that way.
squirming out of those restrictions and starting over with a bilateral fta that is not all of these other things but just an fta - and a second bilateral fta with mexico - is potentially a better future in the long run. but we'll have to convince them it's worth it.