President Donald Trump has opened a new chapter in U.S. trade policy by invoking a rarely used tariff authority, Section 338 of the 1930 Tariff Act, to impose 50% tariffs on a range of Canadian goods. This marks the first time any U.S. president has used this nearly century-old provision, which grants broad authority to impose duties on imports from countries deemed to discriminate against American commerce.

Canada, one of the United States' top trading partners, is the first country targeted under this long-dormant authority. The tariffs cover exports including wine, hockey sticks, cement, dairy products, and furniture, affecting roughly $20 billion in imports. These measures add tension to the already strained trade relationship between Trump and Canadian Prime Minister Mark Carney.

In response, Prime Minister Carney criticized the tariffs as violations of the U.S.-Mexico-Canada Agreement while reaffirming Canada's commitment to ongoing negotiations. Experts like Lincicome have noted that Section 338 could provide a broader legal avenue for imposing tariffs compared to other authorities that face legal challenges or procedural constraints. David Clement, policy director at the Consumer Choice Center, suggested the administration's move aims to preserve Trump's broader tariff agenda despite recent setbacks, while increasing uncertainty for businesses.

Trump's "Liberation Day" tariffs, announced in April 2025, had already imposed broad import duties on dozens of countries. Analysts warn that the bigger long-term risk is not a collapse of North American trade but rather businesses delaying investment due to uncertainty surrounding future tariff policies. The limited scope of the new tariffs may also reflect political considerations ahead of the midterm elections.

This unprecedented use of Section 338 could establish a new legal blueprint for future trade disputes and reshape how trade wars are conducted going forward.

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