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.

Republican lawmakers do not like crossing President Trump, but they also don’t like his trade war, and several are either offering support for the courts or at least trying to stay neutral in the battle.