If President Donald Trump's threat to tariff Canadian imports by 25% goes forward, 200 years of peaceful and profitable Great Lakes maritime trade will be at risk.

Donald Trump's threat to use his executive order power to impose tariffs on goods entering the US from trading partners Mexico and Canada will hit North America's integrated supply chain and could escalate further.

His efforts to “repel the disastrous invasion of our country” by migrants and drugs from Mexico and Canada may soon include stemming the passage of cars. A promise to impose sweeping tariffs on “day one”,