It doesn’t explain why Trump is being so timid with his Tariffs, in fact it makes the opposite assumption.
Trump is just using them as a bullying...er, as a "negotiating tactic" to keep Canada and Mexico jumping to do whatever he wants them too.
Don't get me wrong, its a great power move, one of the most paradigmatic power moves of this century.
But it is incredibly bad public policy. It destroys our relationship with our two biggest trading partners, countries we've lived at peace with for over 150 years. Eventually he's going to cry wolf too many times and Mexico and Canada just get sick of it and will call his bluff.