Posthaste: Trump's tariff tweak just ripped a new swathe through Canada's manufacturing heartland

It was just supposed to simplify administration.

Instead Donald Trump’s tweak to metal tariffs last month has extended the reach of his punishing penalties from a single sector to much of Canada’s manufacturing heart.

Previously the United States applied a 50 per cent tariff to the percentage of steel, aluminum and copper content within a product, but U.S. importers complained that this was too complicated.

Now rather than calculate the value of the metal content, a 25 per cent tariff is applied to the whole product...