The US Supreme Court has struck down President Donald Trump’s broad emergency tariff programme, ruling that the president exceeded his authority by relying on a 1977 emergency statute to impose sweeping duties without congressional approval.

In a six-to-three decision, the Court held that the Constitution vests taxing power in Congress, invalidating tariffs imposed in April 2025 under a declared national emergency tied to trade deficits.

The ruling directly nullifies the reciprocal tariffs applied to imports from most trading partners and follows earlier duties imposed on Canada, China and Mexico under an anti-drug trafficking rationale.

Chief Justice John Roberts, writing for the majority, concluded that the statute invoked does not mention tariffs and cannot be used to create them.

The dissent, authored by Justice Brett Kavanaugh and joined by Justices Samuel Alito and Clarence Thomas, argued that the tariffs were lawful under the statute’s text, history and precedent, even if debatable as policy.

The dissent also warned that the decision leaves unresolved the status of billions of dollars already collected.

Confirmed vs unclear: What is confirmed is that the Court invalidated tariffs imposed under the emergency statute and left in place other, narrower tariff authorities available to the president / What’s still unclear is how and when refund claims tied to more than $133bn collected will be processed and whether alternative statutory routes will sustain parts of the tariff framework.

The Treasury has collected over $133bn in duties under the emergency measures, and companies including Costco have filed refund suits.

The Court declined to decide the refund issue, signalling separate proceedings that could extend for years and complicate importers’ balance sheets.

The Congressional Budget Office has estimated that the broader economic cost of the tariff regime could approach $3tn over a decade, intensifying scrutiny of the programme’s fiscal and consumer effects.

Polling has indicated limited public support amid concerns over living costs.

Administration officials have indicated they will seek to maintain elements of the tariff architecture using alternative statutes that provide more limited authority.

The decision therefore constrains the emergency route while preserving executive tools embedded elsewhere in trade law.

The judgment marks a significant boundary-setting moment between the branches on trade and taxation.

It is the first time a central plank of the president’s declared trade agenda has been invalidated by the Supreme Court during his current term, underscoring the constitutional allocation of revenue powers even as trade policy remains an arena of executive initiative.