What IEEPA is

The International Emergency Economic Powers Act was enacted in 1977 to give the president authority to regulate financial transactions and restrict trade when a national emergency threatens the United States. For nearly fifty years, it was used for targeted economic sanctions: freezing assets, blocking specific transactions, restricting dealings with hostile governments.

In that entire history, no president had ever used IEEPA to impose broad tariffs. The statute authorizes the president to "regulate importation" — language courts and legal scholars had never interpreted to include levying duties, a power the Constitution's text assigns exclusively to Congress.

How the tariffs were imposed

Beginning in February 2025, the Trump administration used IEEPA to impose sweeping tariffs, declaring national emergencies to justify the authority. The orders came in waves:

What the tariffs cost

By the time the Supreme Court ruled in February 2026, the tariffs had been in effect for roughly a year. Their impact was broad and immediate:

Importers absorbed higher costs on goods ranging from electronics and appliances to clothing, food, tools, and auto parts. Most passed those costs through as higher retail prices. Business investment decisions were disrupted by the uncertainty. Supply chains were rerouted. Companies that depended on cross-border manufacturing with Canada and Mexico faced sudden, severe margin pressure with no warning.

The damage was not evenly distributed. Small and mid-sized importers — without the resources to restructure supply chains or absorb the hit — bore a disproportionate burden. For many, the tariffs came as an emergency without the legal grounding that would justify treating them as one.

The legal challenge

Challenges to the tariffs began almost immediately. Importers filed suit in the Court of International Trade, arguing that IEEPA simply does not authorize tariffs and that the "emergency" declarations were legally insufficient. By early 2026, more than 2,000 separate cases had been filed.

The core legal question was narrow: does IEEPA's authority to "regulate importation" include the power to levy duties? The government argued it did. Challengers argued that tariff authority has always required explicit congressional authorization, and that no president — in the nearly 50 years since IEEPA was enacted — had ever claimed otherwise.

The Supreme Court agreed to hear the case on an expedited basis given the scale of economic disruption and the number of affected parties.

The ruling

The Court's majority opinion, written by Chief Justice Roberts, rested on two foundations. First, IEEPA's text: the statute authorizes the president to "regulate importation" — not to levy duties. These are distinct legal concepts with distinct constitutional homes. Second, history: in the nearly fifty years since IEEPA was enacted, no president had ever used it to impose tariffs. That unbroken practice informed how the Court read the statute.

The 6-3 vote crossed ideological lines. The majority included justices appointed by both Republican and Democratic presidents. The breadth of the coalition reflected how clear the legal question ultimately was: this was not a close case about executive power at its limits, but about a president claiming authority the statute plainly did not grant.

What was struck down

Every tariff imposed under IEEPA authority is vacated. That includes: