In February, the U.S. Supreme Court struck down President Donald Trump’s sweeping “Liberation Day” tariffs. Among American commentators, the reaction was immediate and intense. “The Supreme Court dealt President Trump perhaps the biggest blow of his second term,” said the CNN host Fareed Zakaria. The New York Times columnist David French said the case “may prove to be the most important Supreme Court decision this century.” These breathless responses are understandable. Trump had justified the tariffs with a staggeringly broad interpretation of the International Emergency Economic Powers Act, and the ruling was a check on his expansive theory of executive power and a setback for his agenda. It showed that the judiciary will not endlessly defer to his actions. But the case does not solve the underlying challenge facing U.S. trade policy. Trump’s use of the IEEPA may have been uniquely brash, but it did not emerge from a vacuum.…