Canada’s interprovincial trade barriers have been a topic of debate in political and economic circles for years, with little actual progress toward resolving them. But tariff threats from U.S. President Donald Trump have brought new urgency to the issue,

If the U.S. follows through on President Donald Trump's threat to impose massive tariffs on Canada as early as Saturday, Ottawa could hit back with retaliatory tariffs within hours or days, according to international trade lawyers.