OPINION: U.S. Supreme Court's decision on Trump tariffs highlights separation of powers

TOKYO - The U.S. Supreme Court ruled that the tariff measures President Donald Trump invoked under the International Emergency Economic Powers Act were illegal, a decision that matched expectations after even conservative justices had voiced doubts during deliberations. The court's makeup is six conservatives and three liberals, and six justices, including three conservatives, joined the illegality finding.

The ruling, however, was less about ideology than about separation of powers, as the court said the Constitution vests taxing authority in Congress and that the IEEPA does not explicitly grant the president tariff-setting power. It was a reasonable decision that faithfully takes into account the constitutionally defined division of roles between the president and Congress.