For four decades, Canadian commercial life has been organized around the belief that access to the U.S. market was a constant, rather than a variable.

Section 338 of Smoot-Hawley has sat unused for 96 years; Canada's Mark Carney says the move is designed to "destroy" its auto industry.

For four decades, Canadian commercial life has been organized around the belief that access to the U.S. market was a constant, rather than a variable.

Canada has imposed retaliatory tariffs on a wide range of American goods. These measures target sectors like steel, dairy, and appliances, impacting US exports. The move escalates…