Trump invoked IEEPA to launch global reciprocal tariffs.

It can be argued that Trump’s use of the International Emergency Economic Powers Act (IEEPA) to justify the levies was illegal because it does not authorize the president to impose tariffs; rather, it authorizes specific emergency actions, such as sanctions or freezing assets, to protect the nation from foreign threats. Trump also used the IEEPA to launch global “reciprocal” tariffs Wednesday.

But a strong argument is that the president has broad constitutional power on international trade including tariffs.