When it happens, it won't happen all at once. Canada is going to break apart first, at which point the provinces will become part of America separately, either by joining or annexation. This will take several years to fully play out, probably taking longer than Trump's 2nd or even 3rd term.
The barely-populated northernmost provinces will probably be claimed by America right away. This will have such little impact on the lives of the few people living there that they may not even notice. Ontario and Quebec will probably to hold out the longest before they can no longer sustain themselves. When they finally become part of America, it will be at least 100 years before their resentment and bitterness subsides, and it will never fully go away.
Newfoundland will be a different story. Newfoundland is actually the only surviving remnant of Atlantis, which had once been home to a thriving civilization of space travelers. Instead of joining America, they will raise their ancient homeland from the sea and reclaim their cosmic birthright.