The Nuclear Non-Proliferation Treaty
That’s the thing that is supposed to stop the spread of nuclear weapons. Out of 196 countries, 189 have signed, and one country, North Korea, has withdrawn their signature.
Iran signed and claims they are compliant.
India, Pakistan and Israel never signed and all known to have such weapons.
The treaty recognizes the U.S., China, Russia, France and the UK as existing nuclear powers, and they are not required by this treaty to change that status.
So that’s the rundown. It could be a lot better, but frankly, it could be worse, and at the height of the cold war, by 30,000 warheads, it was.