US President Donald Trump announced on Saturday that he is increasing worldwide tariffs on goods entering the United States from 10 percent to 15 percent. He said the move takes effect “effective immediately.”

The decision came just one day after the Supreme Court of the United States struck down much of his broad tariff programme.

Posting on his platform Truth Social, Trump criticised Friday’s ruling. He described it as an “extraordinarily anti-American decision.” He said that after reviewing the judgment, his administration would raise import duties “to the fully allowed, and legally tested, 15% level.”

Court Rejects Use of 1977 Law

Earlier on Friday, the Supreme Court delivered a six-to-three decision against Trump’s use of a 1977 law to impose sudden tariffs on individual countries. The court ruled that the law does not give the president the authority to introduce such duties.

The law in question is the International Emergency Economic Powers Act. Trump had relied on it to justify wide-ranging tariffs that disrupted global trade.

The justices said that “does not authorize the President to impose tariffs.” They added that “had Congress intended to convey the distinct and extraordinary power to impose tariffs” through the law, “it would have done so expressly, as it consistently has in other tariff statutes.”

Chief Justice John Roberts wrote in the majority opinion, “IEEPA contains no reference to tariffs or duties.”

Trump Hits Back at the Court

Trump reacted strongly to the ruling. Notably, he had nominated two of the justices who voted against him. He accused the court, without providing evidence, of being influenced by foreign interests.

“I’m ashamed of certain members of the court, absolutely ashamed, for not having the courage to do what’s right for our country,” Trump told reporters.

He also argued that the judgment does not weaken him. “In order to protect our country, a president can actually charge more tariffs than I was charging in the past,” Trump said. He insisted that the ruling left him “more powerful.”

Treasury Defends Alternative Plan

US Treasury Secretary Scott Bessent addressed the Economic Club of Dallas and explained that the administration has another legal pathway to maintain tariff levels. He said the alternative approach “will result in virtually unchanged tariff revenue in 2026.”

Importantly, the court’s decision did not affect sector-specific tariffs that Trump imposed separately. These include duties on steel, aluminium and other goods. In addition, ongoing government investigations could lead to more sector-based tariffs in the future.

Political and Market Reaction

The ruling marked Trump’s biggest loss at the Supreme Court since he returned to the White House 13 months ago. In many earlier cases, the court had expanded presidential powers. However, this time it set clear limits.

Financial markets responded calmly. Wall Street saw share prices rise slightly after the ruling, which many investors had expected.

Business groups welcomed the decision. The National Retail Federation said the judgment “provides much-needed certainty” for companies that depend on stable trade rules.

Overall, the court’s decision has created a new legal challenge for Trump’s trade policy. At the same time, his move to raise tariffs shows that he intends to continue using trade measures as a central part of his economic strategy.