An Open Letter urging nuclear weapons states to adopt no-first-use and other policies to ensure a nuclear war is never fought has been endorsed by prominent signatories, and was delivered today to leaders of the “nuclear five” or N5 countries -- China, France, Russia, the United Kingdom, and the United States (also known as the P5 because they are permanent members of the UN Security Council) -- and to leaders of the other 185 countries which are States Parties to the NPT.