The United States Supreme Court on Friday struck down the global tariffs imposed by President Donald Trump on Nigeria and several other countries using the International Emergency Economic Powers Act (IEEPA) last year.

Twelve U.S. states, led by Oregon, and five American small businesses had filed a lawsuit against Mr Trump at the United States Court of International Trade, challenging his authority to impose tariffs of such magnitude under IEEPA.

Following judgments in favour of the litigants at the international trade and appellate courts that the president exceeded his authority in imposing the tariffs, the Trump administration filed an appeal with the U.S. Supreme Court to overturn the decision. 

In a 6-3 decision on Friday, the apex court agreed with the lower court’s earlier verdicts and subsequently struck down the sweeping tariffs, citing that Mr Trump erred by invoking a law reserved for national emergencies to target Nigeria and dozens of other countries worldwide.

“The president asserts the extraordinary power to unilaterally impose tariffs of unlimited amount, duration, and scope,” Chief Justice John Roberts wrote in his judgment. “But the Trump administration ‘points to no statute’ in which Congress has previously said that the language in IEEPA could apply to tariffs.”

He added, “We hold that IEEPA does not authorise the president to impose tariffs.”

Justices Clarence Thomas, Brett Kavanaugh, and Samuel Alito dissented.