I have no doubt that Donald Trump will act on all of his worst instincts and take a sledge hammer to America's trading relationships with Canada and the rest of the world.  However, I am not so worried.  

Trump is faced with a real dilemma.  Trump has written far more cheques than he can honor.  He may be able to con his gullible base that he can force America business to do things his way.  But, start frigging with America's trading relationships and it is almost certain that he will precipitate an economic crisis.  

Its like a butcher pretending that he/she can do brain surgery.  It won't end well for the patient.

America is a democracy.  In two years a Republican congress will most likely be decimated.  In that event, you can be certain that Impeachment hearings will follow quickly afterwards.