Why did the Supreme Court strike down Trump's tariffs?

What the Court decided and why it mattered

The Supreme Court concluded that the president lacked statutory authority to impose sweeping global tariffs using an emergency statute. In a 6–3 decision, the majority held that the International Emergency Economic Powers Act (IEEPA) — the 1977 law the administration relied on — did not grant the executive branch clear, broad power to set tariffs on nearly every trading partner. The court’s opinion, issued by the justices in a majority ruling, found that Congress had not plainly delegated that major economic decision to the president.

That ruling turned on two legal ideas. First, the court applied traditional principles of statutory interpretation that require Congress to speak clearly before permitting exercises of extraordinary executive power. Second, the decision reflected the so‑called "major questions" approach: when an agency or the president claims sweeping authority with large political or economic consequences, courts expect an explicit authorization from Congress.

Why it matters

• It reasserts Congress’s central role in large trade choices, returning to lawmakers the primary authority to set tariffs and trade policy.
• It invalidated a core legal theory the administration used to act unilaterally, immediately curbing a signature element of the president’s trade agenda.
• It created near‑term legal and logistical headaches, including questions about existing tariff orders and collections.

The decision does not bar the executive branch from pursuing trade restrictions by other, more limited legal routes. It does, however, limit the ability of a president to rely on a broadly worded emergency statute to reshape trade on a global scale without new or explicit congressional authorization.