In 1984, U.S. President Ronald Reagan noted the nuclear emperor had no clothes: "The only value in our two nations [United States and Soviet Union] possessing nuclear weapons is to make sure they will never be used. But then would it not be better to do away with them entirely"? Indeed it would. The Treaty on the Prohibition of Nuclear Weapons tries to do so through a new normative settling point on the ethics, legality and legitimacy of the bomb.

As of last Friday, 70 states had signed and 26 had ratified the treaty, which will enter into force with 50 ratifications. On Sept. 26, a mini-burst of signatures is expected at the United Nations. Japan is unlikely to sign. It should.

The nine countries with nuclear weapons (China, France, India, Israel, North Korea, Pakistan, Russia, the United Kingdom and the U.S.) reject the treaty. Yet since its adoption in 2017, they have done their best to validate the concerns behind it. This poses a particular problem for several U.S. allies — Australia, Canada, Japan, Norway, etc. — that had previously positioned themselves as ardent advocates of nuclear disarmament.