Fifty years, zero tariffs: How a half-century paper trail sank Trump’s case at the Supreme Court

US Supreme Court says IEEPA doesn’t allow tariffs, citing 50 years of presidents never using it that way. Why 'no precedent' mattered.

• Supreme Court rules Trump can't use IEEPA to impose tariffs
• Court cites lack of historical precedent for tariff authority
• Decision limits presidential power to bypass Congress on tariffs

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President Donald Trump’s lawyers walked into the US Supreme Court with a straightforward argument: a 1977 law meant to handle foreign economic emergencies lets the President impose tariffs.

The Court’s response, written by Chief Justice John Roberts, was equally blunt: if that power were really there, someone would have used it by now.

That simple idea, history as evidence, became a central pillar of the ruling.

A law used for crises, but never for tariffs

For nearly 50 years, presidents from both parties have relied on the International Emergency Economic Powers Act, or IEEPA, to freeze assets, block transactions and impose sanctions. It has been a standard tool in foreign crises.

But they did not use it to impose tariffs.

Roberts treats that omission as meaningful. If IEEPA plainly allowed tariffs, the Court suggests, presidents would have reached for it long before Trump did.

Why 'silence' counts at the Supreme Court

The Court often looks at real-world practice when it interprets old statutes. When a law has existed for decades, has been used frequently, and yet has never been used in a particular way, the justices tend to ask why.

That skepticism sharpens when the claimed power is:

• massive in economic impact,
• easy to trigger, and
• previously unused despite many opportunities.

Here, the Court says the President’s reading would effectively turn IEEPA into a super-statute: declare an emergency, then impose tariffs on any country, on any product, at any rate, for any duration, without the guardrails Congress typically writes into tariff laws.

The tariff whiplash that strengthened the Court’s case

Roberts points to a 'dizzying array' of changes to tariff rates and categories.

The opinion recounts rapid escalations on Chinese goods that pushed the effective rate as high as 145 percent on many imports. It also notes repeated exemptions, suspensions and shifts, evidence, in the majority’s telling, of how unconstrained this claimed power would be.

The Nixon precedent didn’t rescue the government

The administration tried to draw support from IEEPA’s predecessor, the Trading with the Enemy Act (TWEA), pointing to a 1970s episode when President Richard Nixon imposed a temporary import surcharge.

The Court brushes that aside. It notes that only one president relied on that predecessor law to defend tariffs, and even then as a post hoc litigation defence. The surcharge lasted less than five months and was described as temporary and limited.

That history, Roberts suggests, cuts against the idea of an open-ended tariff power.

The deeper point: Tariffs are taxes, and taxes belong to Congress

Underneath the statutory fight is a constitutional principle: tariffs are taxes. And the Constitution assigns taxing power to Congress.

Roberts leans on the 'power of the purse,' the House’s central role in revenue, and the Founders’ insistence on 'taxation without representation.' That framing matters because it changes the burden of proof.

If a president is claiming authority that looks like Congress’s taxing power, Congress must have delegated it clearly. The Court says IEEPA doesn’t.

The Court is not saying presidents can’t use tariffs. It’s saying they can’t “discover” sweeping tariff authority inside an emergency statute that has never been used that way.