How do you pretend to let him win at annexing your country? He wants his place in the history books next to Hitler, and that requires conquest.
I think only domestic unrest will keep him from conquest, and there doesn't seem to be much domestic resistance to his complete takeover.
Annexing Canada or Greenland is just a completely unserious idea, and unless Trump wants America to be a pariah state, he has no cards to play.
Obviously I wasn't referring to pretending to let Trump annex Canada, as no such thing is possible. My point is that you can't literally plan for all contingencies (i.e. repulsing an invasion*); but from a distance, Mark Carney seems to be doing fine. Trump is obviously trying to push Canada into a recession, imagining that will force Ottawa to bend the knee. (Mind you, his global trade war pushes
everyone into a recession.)
So the entire world has to play ball with Trump and pretend that he wins his trade war. Obviously it's tricky and not all countries will take the same strategy. As an American, I support Canada's and China's decision to play "hardball," so to speak. Other countries like Japan and South Korea have chosen to play nice, at least for now.
* Frankly if you think Poland 1939 is the end game, then there's nothing you or anyone can do. The dominant superpower invading a NATO ally is so far off the charts that you can't plan for it to happen, and you couldn't stop it if it did. The Panama Canal seems like a much easier "take," but even that is rather unlikely IMO.