The court’s decision blocks the tariffs Trump slapped last month on almost all U.S. trading partners and levies he imposed before that on China, Mexico and Canada.

In February, he’d invoked the law to impose tariffs on Canada, Mexico and China, saying that the illegal flow of immigrants and drugs across the U.S. border amounted to a national emergency and that the three countries needed to do more to stop it.

The U.S. Constitution gives Congress the power to set taxes, including tariffs. But lawmakers have gradually let presidents assume more power over tariffs — and Trump has made the most of it.

The tariffs are being challenged in at least seven lawsuits. In the ruling Wednesday, the trade court combined two of the cases — one brought by five small businesses and another by 12 U.S. states.

The ruling does leave in place other Trump tariffs, including those on foreign steel, aluminum and autos. But those levies were invoked under a different law that required a Commerce Department investigation and could not be imposed at the president’s own discretion.