Trump Signs Proclamations Banning Some Canadian Imports, Revises Tariff Lists Under Section 338

The White House said Tuesday that President Donald Trump signed five new proclamations under Section 338 of the Tariff Act of 1930, escalating the trade fight with Canada by banning some Canadian goods from entering the United States and rewriting earlier tariff lists issued this summer.

According to a White House fact sheet published Sept. 8, the proclamations do two things: block certain Canadian products from importation and modify the scope of tariffs on other Canadian goods that had been announced on July 20. The administration said the changes focus on sectors already at the center of the dispute, especially alcoholic beverages, dairy products and motor vehicles. The revised tariff coverage takes effect Sept. 15, while the new import bans take effect Sept. 29.

The White House said the Sept. 8 actions include banning certain Canadian alcoholic beverages and dairy products that had previously been subject to 50% duties. It also said the tariff revisions add some products and remove others from coverage. Examples identified by the administration as being removed from tariff coverage include rock salt and Portland cement, while the annexes add some motor vehicles, auto-related products and additional dairy lines.

The move came hours after Canada’s latest retaliatory tariffs took effect. Canada’s Department of Finance said, “These new countermeasures on $27.6 billion in products imported from the U.S. will be effective as of 12:01 a.m., September 8, 2026.” The White House said Trump’s response was aimed at that step and at what it called Canada’s “continued discriminatory treatment” of U.S. exports. “President Trump is taking decisive and appropriate action to respond to Canada’s additional retaliation and continued discriminatory treatment of crucial American exports,” the fact sheet said.

The administration said the new Section 338 measures apply whether or not a product qualifies as North American under the U.S.-Mexico-Canada Agreement, the regional trade pact governing trade among the three countries. It also said the measures apply on top of tariffs already imposed under Section 232, the national-security trade authority the U.S. has used in other import cases.

Beyond border measures, the White House said Trump directed the Office of the U.S. Trade Representative and the General Services Administration, which manages federal purchasing, to remove “$50 billion dollars’ worth of Canadian-origin products” from the GSA’s Multiple Award Schedules, a major federal procurement system. That extends the response beyond customs duties and into government purchasing.

The proclamations cite Section 338 of the Tariff Act of 1930 as the authority for the duties and exclusions and Section 604 of the Trade Act of 1974 for changes to the Harmonized Tariff Schedule, the tariff system used by U.S. Customs and Border Protection. CBP will handle the tariff-schedule changes and enforcement, according to the White House.

Tuesday’s action builds on the administration’s July 20 proclamations, which imposed additional ad valorem duties — tariffs charged as a percentage of a product’s value — of up to 50% on specified Canadian goods. Those duties were briefly suspended and then took effect at 12:01 a.m. Eastern on Aug. 22.

The use of Section 338 is also legally notable. A Congressional Research Service report dated March 19, 2026, said, “As of the time of this writing, the United States has never imposed tariffs under Section 338.” That makes the administration’s reliance on the provision this year an unusual revival of a rarely used trade authority.