On February 20, 2026, the Supreme Court delivered a significant blow to the Trump administration’s trade agenda, voting 6–3 to strike down the president’s broad tariff program. Chief Justice John Roberts wrote the majority opinion, joined by Justices Neil Gorsuch and Amy Coney Barrett on the conservative side, along with the court’s three liberal members. Justices Thomas, Kavanaugh, and Alito sided with the administration. The core finding was straightforward: the International Emergency Economic Powers Act simply does not give a president the power to impose sweeping tariffs.

The path to this decision wound through several years of litigation. American businesses challenged the tariffs in federal court, and in mid-2025 a unanimous panel at the U.S. International Court of Trade agreed they were unlawful. An appeals court affirmed that conclusion a few months later, and the Supreme Court heard arguments in November before issuing its ruling in February.

The financial stakes are enormous. By the time the ruling came down, U.S. importers had paid well over $160 billion under the now-invalidated IEEPA duties, a figure that could reach nearly three-quarters of all new tariff revenues collected under the Trump trade agenda. The case has been sent back to lower courts to determine whether and how refunds will be issued, and the government has not disputed that it may be required to return those payments. For American households, the IEEPA tariffs had contributed to what economists described as the largest tax increase as a share of national output in over three decades, adding roughly $1,000 per family in 2025 and a projected $1,300 in 2026.

However, the ruling leaves intact the tariffs that have done the most damage to specific industries. Levies on steel, aluminum, automobiles, and heavy trucks, imposed under a separate statutory authority known as Section 232, were untouched by the court. Those measures alone are projected to generate over $600 billion in revenue over the coming decade, at a cost of approximately $400 per U.S. household annually.

For Canada, the ruling’s direct impact is narrower than headlines might suggest. The vast majority of Canadian goods crossing into the United States already move tariff-free thanks to CUSMA compliance, and by some estimates nearly 90% of Canadian exports qualified for exemptions even while the IEEPA tariffs were in force, meaning the struck-down measures applied to less than 5% of what Canada ships south. The heavier burden has always come from sector-specific duties, which remain in effect.

The pain in those sectors is real. Canadian steel shipments to the U.S. collapsed in early 2026, falling by more than two-thirds compared to the same period a year earlier, a loss that translates to billions of dollars in annual export revenue. Lumber, copper, and auto parts producers face similar conditions.

Any sense of relief from the ruling may prove brief. Within days of the decision, the administration announced a new across-the-board 10% surcharge under a different legal provision, the Trade Act of 1974, with signals that it could climb to 15%. CUSMA-compliant Canadian goods are currently shielded from this new measure, which means non-qualifying imports from Canada would actually see their effective tariff rate fall from the previous 35% IEEPA level. Legal challenges to the new surcharge have already been filed, with opponents arguing the administration has not met the law’s requirements for invoking it. Separately, the administration launched Section 301 trade investigations into more than a dozen countries and the European Union in mid-March.

The most consequential near-term development for Canada may be diplomatic rather than judicial. Under the terms of CUSMA itself, the three signatory nations are required to convene a formal review this July to assess how the agreement is functioning. The deal remains in force until 2036, but whether it is extended or allowed to drift toward annual renegotiations will depend heavily on that meeting. Protecting Canada’s standing under CUSMA has emerged as a more urgent priority than any court outcome.

The Supreme Court’s ruling closes off one avenue the administration used to reshape global trade, but it does not close the book on tariff uncertainty. With new legal tools already in play, new investigations underway, and the CUSMA review approaching, Canadian businesses face a landscape that demands both strategic diversification and close attention to the rules that currently protect their access to the U.S. market.

---

References

1. Learning Resources, Inc. v. Trump, 607 U.S. ___ (2026) — Full opinion: supremecourt.gov — Case summary: SCOTUSblog — Wikipedia overview: en.wikipedia.org
2. Tax Foundation, analysis of IEEPA tariff revenues, household costs, and Section 232 projections: taxfoundation.org — Updated tariff tracker: taxfoundation.org
3. Yale Budget Lab, post-ruling tariff impact analysis (February 21, 2026): budgetlab.yale.edu
4. Congressional Research Service, IEEPA tariff refund pathways: congress.gov — Supreme Court ruling summary: congress.gov
5. BDO, IEEPA tariff refund FAQ (March 2026): bdo.com
6. Cato Institute, IEEPA tariff analysis and refund estimates: cato.org
7. RBC Economics, Canadian export exposure under IEEPA and CUSMA: rbc.com
8. CBC News, Canadian tariff exposure post-ruling: cbc.ca
9. Fastmarkets, Canadian steel export data January 2026: fastmarkets.com
10. CUSMA Article 34.7, joint review provisions — Federal Register (USTR public consultation, September 2025): federalregister.gov — McCarthy Tétrault guide for Canadian stakeholders: mccarthy.ca — Congressional Research Service overview: congress.gov