But why are we not at zero? Because there is some kind of value in possessing nuclear weapons. There were so many nuclear weapons that it didn't really hurt to get rid of a lot of them, the really meaningful steps are getting rid of the last hundred, the last ten and of course the last one. So as long as the nuclear powers keep a couple of them they keep most of the value of being a nuclear power while denying that value to all other countries seeking this power. The USA could really strengthen their position by just getting rid of all its nuclear weapons. And even then they would still be in a better position because there is still the knowledge to build new ones.