However, the fuel cycle, spent fuel reprocessing, and nuclear material controls for nuclear-powered submarines substantially overlap with pathways for developing nuclear weapons. Japan already stockpiles large quantities of separated plutonium and has well-established reserves of nuclear material, reactor-technology expertise and delivery-platform foundations. Should Tokyo achieve the technical and political breakthrough of "introducing nuclear-powered submarines," no insurmountable technical gap would stand in the way of it later developing its own nuclear warheads. "Buy the submarines first, then acquire nuclear-weapon capability" is the roadmap quietly plotted by Japan"s right-wing forces.

　　The US is aware of these risks, yet it has long turned a blind eye. Some US politicians harbor opportunistic calculations regarding Tokyo: They want to arm Japan as their forward‑edge spearhead in East Asia and make Japan bear more of the costs of confrontation. They imagine they hold the reins and can keep this "proxy tool" firmly in check to prevent it from turning on its master. This mind-set is steeped in short‑sighted arrogance. In essence, it gambles with the postwar international order and the non‑proliferation regime, allowing the dangerous "Pandora"s box" to be slowly opened for the sake of short-term geopolitical gains.