On Sept. 4, U.S. President Donald Trump issued an executive order that brought an interim conclusion to the U.S.-Japan tariff negotiations, which had been ongoing since April.

While tariffs on automobiles and auto parts were reduced to 15% — a priority for Tokyo — the deal came at a steep cost: Japan was compelled to accept a memorandum on investment commitments heavily tilted in Washington’s favor.

The Trump administration’s second-term tariff strategy represents a sharp departure from the principles of the postwar international trading system, and in many ways, it signals the end of that system. To understand why, it is crucial to examine U.S. tariff policy through a geoeconomic perspective: how the administration wields power, how targeted countries might respond and what kind of international trade order could emerge if free trade truly gives way.