It is of the utmost importance that Canada start acting like Canada Inc. as in Japan Inc. Singapore Inc. Ireland Inc. and others. Interprovincial trade is far from free,  movement of labour is riddled with restrictions. The coast to coast railway played a large part in the survival of this country, coast to coast pipelines are not allowed. Alberta and Saskatchewan oil is locked out of international markets because it cannot access the Atlantic or Pacific. The result is the US is our sole customer and the discount from the international price we receive reflects that.
From 1922 to 1932 Ireland had a healthy trade surplus with the US. Then without notice the US placed a 30%+  import duty on all imports from Ireland, within a week Ireland placed a 60% + import duty on all import from the US. I hope that Canada has the guts and backbone to retaliate immediately against bully boy tactics coming from any country.  Canada has been moving to widen its export markets with the recent CETA.