The rulings against the levies in two federal courts – the U.S. Court of International Trade and the U.S. District Court in Washington, D.C. -- centered on Trump's unprecedented invocation of the International Economic Emergency Powers Act as a legal justification for tariffs.

The court said Mr. Trump's global 10% tariffs aren't authorized by IEEPA because they're designed to deal with trade imbalances between the U.S. and the rest of the world, which the judges said should fall under non-emergency legislation.