Days after the Supreme Court struck down his broad tariffs, Trump claims the ruling strengthens his authority and announces a new 15% global levy under the Trade Act of 1974. The move targets all US trading partners and aims to maximise leverage in international trade. Days after the Supreme Court struck down his broad tariffs, Trump claims the ruling strengthens his authority and announces a new 15% global levy under the Trade Act of 1974. The move targets all US trading partners and aims to maximise leverage in international trade.