Prime Minister Trudeau has committed to using a “whole suite of tariff and countervailing duties” to prevent a surge in imports of steel and aluminum once the U.S. implements its section 232 tariffs. That’s driven by the dual aims of protecting Canadian business from products diverted from U.S. sales, as well as avoiding Canada becoming a “gateway” for transshipped products to the U.S. from other countries. Canada’s global exports of all metals/mineral manufactured products rose 13% in the 12 months to January 30. Maintaining an exemption from U.S. tariffs is critical given the section 2...