On July 1, the 1968 Nuclear Non-Proliferation Treaty (NPT) turned 50 years old. In that agreement, five nuclear weapons states— the US, Russia, UK, France, and China—promised, a half a century ago, to make “good faith efforts” to give up their nuclear weapons, while non-nuclear weapons states promised not to acquire them. Every country in the world agreed to join the treaty except for India, Pakistan, and Israel which then went on to develop their own nuclear arsenals.