The Supreme Court on Friday ruled that President Donald Trump violated federal law when he unilaterally imposed sweeping tariffs across the globe, a striking loss for the White House on an issue that has been central to the president’s foreign policy and economic agenda.

The decision is arguably the most important loss the second Trump administration has sustained at the conservative Supreme Court, which last year repeatedly sided with the president in a series of emergency rulings on immigration, the firing of the leaders of independent agencies and deep cuts to government spending.

Chief Justice John Roberts wrote the majority opinion and the court agreed 6-3 that the tariffs exceeded the law. The court, however, did not say what should happen to the more than $130 billion in tariffs that has already been collected.

“The president asserts the extraordinary power to unilaterally impose tariffs of unlimited amount, duration, and scope,” Roberts wrote for the court. “In light of the breadth, history, and constitutional context of that asserted authority, he must identify clear congressional authorisation to exercise it.”

The emergency authority Trump attempted to rely on, the court said, “falls short”.

Trump received the news of the tariffs in a note while he was meeting with governors at the White House on Friday morning.

After he read the note, he said aloud, “That’s a disgrace,” and then left the room shortly after, according to a governor in the room.

The president and Justice Department officials had framed the dispute in existential terms for the country, telling the justices that “with tariffs, we are a rich nation” but that without them, “we are a poor nation”. A group of small businesses, which challenged the duties similarly, warned that Trump’s position represented a “breathtaking assertion of power” to effectively levy a tax without oversight from Congress.