A container ship can take weeks to cross an ocean, but a tariff can land overnight, printed onto a customs form like an unavoidable surcharge. On Friday, the US Supreme Court said President Donald Trump did not have the power to impose that kind of sweeping import tax by declaring an emergency and checking a broad statutory box.

The ruling knocks out the bulk of Trump's tariff program, a signature part of his second-term economic strategy and a tool he has used to lean on allies and rivals alike. It also opens the door to a messy, expensive aftershock: companies that paid billions under now-invalidated levies are expected to press for refunds, even though the court did not set out a clear process for getting that money back.

The justices ruled 6–3 that the International Emergency Economic Powers Act, or IEEPA, does not authorize a president to impose tariffs. Chief Justice John Roberts wrote that the court was not pretending to be an economic ministry or a foreign policy shop, only doing the job the Constitution assigns judges, and concluded that 'IEEPA does not authorize the President to impose tariffs.'

Trump's approach was unusual in a straightforward way. No president, in IEEPA's nearly 50-year history, had tried to use it as a tariff statute, even though tariffs have traditionally been understood as a taxing power rooted in Congress.

The administration argued that IEEPA's language allowing the president to 'regulate' importation during an emergency was broad enough to cover tariffs, but the majority was not persuaded that Congress had handed over authority on that scale without saying so plainly.

The underlying measures were expansive. The legal fight centered on Trump's IEEPA-based tariffs that reached across countries and products, including orders tied to a fentanyl-related emergency affecting trade with Canada, China, and Mexico, and later tariffs framed around trade deficits and 'reciprocal' rates imposed on a wide set of partners.

Not every Trump tariff disappears with this ruling. Reporting on the decision emphasized that sector-specific duties imposed under separate legal authorities, including tariffs on metals such as steel and aluminum, were not before the court and remain in effect.

If the legal logic is crisp, the financial cleanup is not. The Supreme Court did not spell out whether importers will be made whole, leaving the refund fight to lower courts and, quite possibly, to years of follow-on litigation over who is entitled to what.

CNBC cited an estimate that the US could owe more than $175 billion in refunds after the decision, a figure that hints at the scale of the problem even before the details are tested case by case. Some companies clearly did not want to wait around to discover whether a favorable Supreme Court ruling would automatically translate into a check from Washington.

Costco is one of the most prominent examples. In its court filings, the retailer argued that even if the tariffs were ultimately deemed unlawful, importers who paid them were 'not assured a refund' without their own judgments and judicial relief, pointing to warnings from the Court of International Trade and the Federal Circuit about how difficult it can be to claw back duties once entries have liquidated.

Source: International Business Times UK