Supreme Court decision against Trump's tariffs raises uncertainty, but markets stay calm

BANGKOK — The Supreme Court's ruling against U.S. President Donald Trump's tariffs has countries like China and South Korea watching for Washington's next steps, while financial markets took the news in stride.

The decision announced Friday could potentially disrupt arrangements worked out in trade negotiations since Trump announced sweeping tariffs on dozens of countries in April 2025.

China's Commerce Ministry said it was conducting a ''comprehensive assessment of '' the ruling against the tariffs Trump imposed under the International Emergency Economic Powers Act, or IEEPA.

''China urges the United States to lift the unilateral tariffs imposed on trading partners,'' an unnamed ministry spokesman said in a statement.

The statement reiterated Beijing's stance that there are no winners in a trade war and that the measures Trump had announced ''not only violate international economic and trade rules but also contravene domestic laws of the United States, and are not in the interests of any party," the official Xinhua News Agency cited the spokesperson as saying.

Trump responded to the Supreme Court decision by proposing a new 10% global tariff under an alternative law, Section 122 of the 1974 Trade Act, and later increased it to 15%.

For China and some other countries in Asia that were subject to higher import duties on their exports, that could potentially bring some relief. But for others such as Japan, the United Kingdom and other U.S. allies, tariffs could rise.

''The deals were not premised on whether or not the emergency tariff litigation would rise or fall,'' said Greer, Trump's top trade negotiator. ''I haven't heard anyone yet come to me and say the deal's off. They want to see how this plays out.''

Uncertainty may worsen if the Trump administration continues imposing new tariffs under alternative laws, South Korea's trade minister, Kim Jung-kwan, said Monday.

The South Koreans have agreed to hold ''amicable'' discussions with U.S. officials in order to minimize any negative impact on South Korean companies, he said. Major South Korean exports such as autos and steel are subject to tariffs under other trade laws.

''Given the uncertainty over future U.S. tariff measures, the public and private sectors must work together to strengthen our companies' export competitiveness and diversify their markets,'' Kim said.

U.S. Treasury Secretary Scott Bessent also said Sunday that he believed trading partners would abide by existing deals and that tariff revenues will remain steady.

The administration would defer to the courts on whether to give companies refunds for the import taxes already collected under the tariffs now declared unlawful, Bessent said.

''It's out of our hands and we will follow the court's orders,'' he said.

U.S. futures sank early Monday, with the contract for the S&P 500 down 0.6% and that for the Dow Jones Industrial Average falling 0.5%. Oil prices fell and the U.S. dollar weakened against the Japanese yen and the euro.

But share prices in Asia mostly advanced, with Hong Kong's Hang Seng gaining 2.4%.

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