What is Section 338 of the Tariff Act of 1930, and why is Trump’s use of it legally unprecedented?

Section 338 of the Tariff Act of 1930 authorizes the president to impose tariffs of up to 50% on imports from countries that have discriminated against U.S. businesses; it has never been used before by any president, making Trump’s invocation of it — to levy a 50% tax on $20 billion worth of Canadian imports — the first and only application of this obscure, 96-year-old statute, which legal experts describe as 'a blank canvas because it’s never been litigated.'

Why do some legal scholars argue that Section 338 may no longer be valid or enforceable?

Some lawyers and legal scholars argue that Section 338 has likely been superseded by later trade laws — such as the Trade Expansion Act of 1962 and the Trade Act of 1974 — which granted the president new, more constrained tariff authorities tied to specific conditions (e.g., national security threats) and procedural requirements, suggesting Congress implicitly repealed or displaced the broad, unqualified power in Section 338 by enacting these subsequent, more detailed statutes.