FILE – President Donald Trump speaks with Canadian Prime Minister Mark Carney, right, at a working lunch with leaders of G7 and the Middle East in Evian-les-Bains, France, Tuesday, June 16, 2026. (Evelyn Hockstein/Pool Photo via AP,File) President Trump has reached deep into the trade law archives to wage his latest tariff campaign against Canada.
On July 20, he invoked Section 338 of the Tariff Act of 1930 to impose a new 50 percent tariff on roughly $20 billion of Canadian imports. It is the first time the nearly century-old statute has been used this way.
The products are a curious mix: hockey sticks, wine, cement, furniture, clothing, fishing rods and swimming pools. But the tariff itself isn’t the real story. The administration has quietly changed the legal and political theory of the U.S.-Canada trade war.
For years, Washington treated Canada’s actions as retaliation. Trump is now calling them discrimination.
Retaliation implies reciprocity. One country imposes tariffs; the other responds, and both claim they’re merely answering the other’s actions. Neither side looks innocent. The dispute becomes another round of escalation. Discrimination is different. Section 338 does not authorize tariffs simply because another country retaliates. It authorizes them when a country treats American commerce worse than commerce from other nations.
The White House is no longer saying Canada merely answered American tariffs. It argues Canada deliberately disadvantaged U.S. producers while giving competitors from elsewhere better treatment.
The administration points to Canadian auto quotas, provincial restrictions on American alcohol and dairy tariff-rate quotas that allegedly favor European cheese over U.S. exports. But those allegations are contestable, and one rests on shaky ground. The alcohol case turns on provincial liquor boards pulling U.S. bottles, a decision Ottawa did not make. Section 338 is the rare statute whose text lets Washington treat a province’s choice as the country’s discrimination.
Instead of asking whether Canada’s response was justified, it is asking whether Canada crossed the line from reciprocal retaliation to unequal treatment. That is a much stronger negotiating position.
For four decades, U.S.-Canada trade disputes followed the same script. Washington imposed duties. Ottawa retaliated. Canada challenged them under the North American Free Trade Agreement, the World Trade Organization or the United States-Mexico-Canada Agreement. Lawyers won cases. Politicians settled. The cycle repeated.
Trump’s Section 338 proclamation suggests the administration is losing patience with that cycle. Rather than waiting for another round of litigation, it is using an almost-forgotten statute to redefine the dispute itself. But the statute has limits: It caps the additional duties at 50 percent and ties them to the discrimination found. A flat rate across unrelated goods is hard to call the tailored offset the law contemplates.
The choice of products reinforces that strategy. Many of the targeted industries are concentrated in Ontario and Quebec, Canada’s manufacturing heartland and its most politically influential provinces. The administration, meanwhile, largely spared the sectors America cannot easily replace, including energy, potash, critical minerals and products already covered by Section 232 tariffs.
This is not indiscriminate protectionism. It is economic pressure designed to maximize political leverage while minimizing disruption to North American supply chains.
The delayed implementation date tells the same story. The tariffs will not take effect until Aug. 19. That gives both governments weeks to negotiate over cars, alcohol and dairy before the duties bite. These tariffs are leverage first and revenue second.
Prime Minister Mark Carney has already responded by promising intensified negotiations rather than another immediate round of retaliation. That may prove Trump’s biggest victory, but it need not be. Ottawa can negotiate and litigate at once.
Canada will also argue that its measures were themselves responses to earlier U.S. tariffs, not independent acts of discrimination. Whether Section 338 applies in those circumstances has never been tested in modern courts.
Canada’s stronger ground is the remedy and the statute’s novelty. The law allows duties only to offset the specific discrimination found, and a flat 50 percent across unrelated goods offsets nothing in particular. Because Section 338 has never been used in its 96 years, no court has ever construed it — so reviving a dormant power this way, to override the U.S.-Mexico-Canada Agreement, invites a challenge of its own.
Canada will also argue that its measures were themselves responses to earlier U.S. tariffs — countermeasures, not discrimination. But Section 338 asks only that the president find discrimination, with no investigation and no process, so the finding itself is nearly unreviewable.
If the strategy succeeds, its implications extend far beyond Canada. Other governments that selectively target American exports in future trade disputes could find their actions recast not as lawful countermeasures but as discrimination subject to Section 338.
The bigger warning is where this points next. The same discrimination theory is already aimed at Canada’s AI policy, privacy and data rules, the next measures Washington can recast as discrimination against American technology firms, even as it warns it would override signed trade deals.
Trump has done more than impose another tariff. He has tried to rewrite the rules of North American trade diplomacy.
Marc L. Busch is the Karl F. Landegger Professor of International Business Diplomacy at the Walsh School of Foreign Service, Georgetown University. Barry Appleton is Interim Director of the Balsillie Legal Advisory Centre at the Balsillie School of International Affairs and Co-Director of the Center for International Law at New York Law School.
Add as preferred source on Google Tags alcohol tariffs Canada canada tariffs canada us relations Canadian Prime Minister Mark Carney Discrimination Donald Trump Donald Trump tariffs manufacturing North American Free Trade Agreement ontario Ottawa President Trump Quebec retaliation Section 338 Tariff Act of 1930 Trade wars trump United States-Mexico-Canada Agreement United States-Mexico-Canada Agreement (USMCA) US-Canada relations Washington white house World Trade Organization World Trade Organization (WTO)Copyright 2026 Nexstar Media Inc. All rights reserved. This material may not be published, broadcast, rewritten, or redistributed.
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