Trump's 2026 Canada tariffs spark legal debate over forgotten trade law

President Donald Trump announced a series of tariffs on Canadian imports in 2026, citing Section 338 of the Tariff Act of 1930, a little-known authority that permits up to a 50% levy when a foreign country unfairly treats American goods. The clause, dormant since the 1940s, was highlighted by former deputy trade representative John Veroneau and colleague Catherine Gibson as a potential tool for unilateral action. However, a recent Supreme Court ruling, split 6-3, found the president’s use of the provision largely invalid.

Legal commentators such as Hoover Institution historian Philip Zelikow argue later statutes have implicitly superseded Section 338, narrowing its applicability. Georgetown trade lawyers further contend that the president’s justification—alleged Canadian discrimination in automobiles, alcohol and dairy—does not meet the statute’s requirements, especially since alcohol regulation is a provincial matter. The combination of an outdated law and a narrow judicial rebuke casts doubt on the durability of the tariff regime.