President Donald Trump has imposed 50% tariffs on a range of Canadian goods by invoking Section 338 of the Tariff Act of 1930, a provision that has never previously been used by any US president. The move marks an expansion of Trump's approach to trade policy, giving him a broad and largely untested legal tool that could set a precedent for how future administrations wage trade disputes.

Section 338, dating back nearly a century, grants the president wide-ranging authority to impose duties on imports, and its use against Canada signals a more aggressive phase in the ongoing tariff dispute between the two neighbouring economies. Analysts have warned that shifting and unpredictable tariff policies are creating "economic chaos" and discouraging business investment, even though the deep trade ties between the US and Canada make a complete rupture unlikely.