Trump’s Korea pivot exposes Japan’s lack of a Plan B

An FT opinion argues Trump’s move to curb US-South Korea drills unsettles alliance guarantees, risking instability in Asia. If US assurances look unreliable, Japan’s long-standing Plan A (rely on the US, maintain pacifist constitution) becomes fragile, and a credible Plan B — rearmament or deterrence — remains politically awkward. Japan’s Defence of Japan white paper signals some buildup by 2027, but not a true Plan B. Domestic protests in Tokyo underscore public resistance to abandoning pacifism, while Tokyo weighs how to respond to a potentially more uncertain security environment.