On September 8, 2026, President Donald J. Trump signed five proclamations under Section 338 of the Tariff Act of 1930 (19 U.S.C. 1338) escalating the measures imposed on Canada in July. Three of them exclude from importation certain Canadian products that have been subject to 50% Section 338 duties since August 22, 2026, relating to alcoholic beverages, dairy, and motor vehicles. The import bans take effect for goods imported on or after 12:01 a.m. eastern time on September 29, 2026.
Section 338 authorizes the President to exclude a country’s products from importation if it maintains or increases discrimination against U.S. commerce. The motor-vehicle proclamation, for example, finds that Canada maintained the discrimination identified in Proclamation 11048 after the 50% duties took effect; the fact sheet describes parallel findings for alcoholic beverages (Proclamation 11046) and dairy (Proclamation 11047).
Section 338 was never used to impose tariffs. Historical records indicate that in the 1930s, the government undertook both general monitoring of trade relations and investigation of individual complaints pursuant to Section 338, but no formal actions took place under this provision.
Key terms
- Scope. The bans apply to the Canadian products listed in the annex to each proclamation, all drawn from products already subject to the 50% Section 338 duties. Products not moved to the bans remain subject to the 50% duties.
- Timing trigger. The bans apply to goods imported on or after September 29. Covered goods imported before that date but not yet entered for consumption, or withdrawn from warehouse for consumption, remain subject to the 50% duty rather than the ban.
- No USMCA exception. According to the White House fact sheet, the Section 338 measures apply regardless of whether a good originates under the U.S.-Mexico-Canada Agreement (USMCA), and the duties apply in addition to Section 232 tariffs.
- Fallback. If a ban is held invalid in whole or in part, the 50% duty applies instead to the affected imports.
Scope changes already in effect
A separate proclamation modified the list of products subject to the 50% duties, effective for goods entered on or after September 15, 2026. According to the fact sheet, it removed certain products, such as rock salt and cement, and added others, ranging from all-terrain vehicles to additional dairy products. U.S. Customs and Border Protection (CBP) issued filing instructions for the scope change in CSMS # 69851916. The fact sheet also states that the President directed USTR and the General Services Administration to remove Canadian-origin products from GSA’s Multiple Award Schedules.
Immediate Considerations
Importers of Canadian goods should confirm today whether any product appears on the annexes to the three import-ban proclamations, and should coordinate with carriers and brokers on shipments that may arrive on or after September 29, because a shipment that crosses the border after the effective time would be excluded rather than dutiable. Goods already imported should be entered, or placed in warehouse, promptly to preserve treatment under the 50% duty. Companies should also confirm classification against the September 15 scope changes and watch for further CBP guidance implementing the bans.
Please contact us should you wish to discuss the impact on your products or supply chain.