Given Japan is the emotional touchstone of nuclear weapon policy, its stance on the U.N. ban treaty is not just a deeply flawed misreading of international sentiment. It is also a deep betrayal of Japan’s own history, legacy and people. By coincidence the two highest international public offices in this sector, the IAEA director general and the U.N. secretary-general’s high representative on disarmament, are both currently held by Japanese. Both are likely to be somewhat embarrassed by Tokyo’s nuclear timidity.