U.S. Supreme Court voids Trump tariffs, rattles trade policy and global partners
The U.S. Supreme Court on Thursday ruled that tariffs imposed by former President Donald Trump under the International Emergency Economic Powers Act (IEEPA) were unlawful, dealing a major blow to his trade strategy. The invalidated measures included reciprocal tariffs introduced globally in April last year, as well as duties on China, Mexico and Canada, which the administration had justified as a response to the inflow of the narcotic fentanyl.
Following the ruling, Trump swiftly invoked Section 122 of the Trade Act, imposing a substitute 10 percent tariff on all countries and raising the rate to 15 percent the next day. Although he sought to preserve the impact of the original tariffs through alternative executive actions, analysts say the judgment strikes at the core of his economic agenda, blocking what had been widely regarded as a central pillar of his trade policy.
In its opinion, the court held that the IEEPA, enacted in 1977, does not grant the president unilateral authority to impose sweeping import tariffs without congressional approval. The justices said Trump had claimed extraordinary powers without limits on quantity, duration or scope, adding that such authority would require explicit authorization from Congress. Six of the nine justices ruled the reciprocal tariffs unlawful, including Chief Justice John Roberts, as well as Neil Gorsuch and Amy Coney Barrett.
Reacting at a White House news conference, Trump criticised the decision, claiming countries that had “exploited” the United States were celebrating, and formally announced the 10 percent substitute tariff. He later wrote on Truth Social that the rate would immediately rise to 15 percent — the maximum allowed under Section 122, which permits temporary tariffs of up to 15 percent for 150 days to address trade deficits.
Meanwhile, South Korea said it would proceed with the November memorandum of understanding on South Korea–U.S. strategic investment despite the ruling. The presidential office signalled that there was little reason to provoke Washington at a time when the legal basis of U.S. tariff policy has been thrown into uncertainty.
A senior official said the administration may adopt a more complex and cautious response, acknowledging that the ruling had placed the government on the defensive and that renegotiation would be difficult. The presidential office held an interagency meeting on South Korea–U.S. trade relations, chaired by National Security Adviser Wi Sung-lac and Presidential Policy Chief Kim Yong-beom, with another tariff-focused trade review meeting also convened on Friday.
