To approach this from a different angle, the word within the party (I am a long-serving campaign worker, manager, and PAC-server) is that as far as Canada is concerned, the tariff is a leverage chip, probably for greater border cooperation in terms of fentanyl and illegals.
I have also heard that it may be to help a prospective Conservative candidate when replacing Castro Jr comes around, although I don't know enough about Canadian politics to know if that is credible.
But nearly everything being done on the foreign stage right now is for dramatic effect and future deal-making.