whats stopping canada the rest of the world from calling our bluff? like they can literally shut us down overnight and what would the presidemt do? nothing.

Full tit-for-tat retaliation for tariffs? That'd harm our own economy as much as the U.S.'s. We want fewer tariff's. Not more.

Trump is most likely just trying to distract people from his Iran debacle, the cover-up of his involvement in the Epstein scandal, or whatever it is he's trying to do with the midterm elections. He's unlikely to follow through. It's better to wait and see what he actually does before taking any action.