Two years ago, the prospect of a trade war between the United States and Canada, two of the world’s most closely integrated economies, would have been unthinkable. However, US President Donald Trump’s recklessness and capriciousness know no bounds. Last week’s breakdown in negotiations between the North American neighbours, which triggered the imposition of US tariffs of 50 per cent on a wide range of Canadian goods, showed the degree to which Trump’s trade policies are vindictive, politicised...