- Lead. President Trump signed three proclamations on July 20 imposing an additional 50% tariff on a broad range of Canadian goods effective August 19 — the third major US tariff action against Canada in 2026.
- Fact. The proclamations invoke Section 338 of the Tariff Act of 1930, a provision unused in the modern tariff era, and cover more than 550 Harmonized Tariff Schedule subheadings including dairy, alcoholic beverages, motor vehicles, cement and sporting goods.
- Stake. Unlike the Section 122 action earlier this year, these tariffs carry no fixed expiry date and USMCA/CUSMA compliance provides no exemption, meaning they remain in force indefinitely unless explicitly lifted.
The effective date for Washington’s latest Canada tariffs is now eight days away, and the practical scope of the three presidential proclamations signed on July 20 is wider than early headlines suggested. Analysis from Mondaq and PwC Canada confirms that more than 550 Harmonized Tariff Schedule subheadings are covered across the three separate proclamations. While dairy products, alcoholic beverages and motor vehicles feature prominently in official framing, the tariff annexes extend to agricultural inputs, horticultural products, cement, electronics components, building materials and apparel, among others.
A Rarely Invoked Statute
The Trump administration’s use of Section 338 of the Tariff Act of 1930 marks the first application of the provision in the modern tariff era, according to legal experts cited by multiple trade law firms. The statute allows a president to impose duties of up to 50% on goods from a country found to discriminate against US commerce. The three proclamations describe Canada’s treatment of US dairy, alcohol and motor vehicle exports as “discriminatory,” providing the legal hook for the 50% rate.
The choice of Section 338 carries practical consequences that distinguish this action from earlier tariff actions against Canada. The Section 122 measures used previously came with a statutory 150-day ceiling. Section 338 carries no such expiry, meaning the 50% duties on the covered product lines will remain in place indefinitely without a separate presidential action to remove them.
USMCA Compliance Provides No Cover
The proclamations explicitly state that the additional 50% tariff applies regardless of whether goods qualify for preferential treatment under the Canada-United States-Mexico Agreement. Canadian exporters that have relied on USMCA certification as a tariff shield face a new calculation: CUSMA compliance does not reduce the Section 338 burden, and the duties stack on top of all existing tariffs, taxes, fees and charges already in effect.
Canada’s government and business groups have called the action unjustified and said a retaliatory response is under consideration. The impact is expected to fall most immediately on dairy and alcohol supply chains, sectors that are both politically sensitive and significant bilateral trade categories. With August 19 approaching and no resolution in sight, importers and manufacturers on both sides of the border are moving to adjust procurement schedules and contracts before the duties take hold.