August 6th is the 70th anniversary of the nuclear destruction of Hiroshima.
We still have these weapons.
The key question about nuclear weapons is this: Is the deterrence system infallible? Is it impossible that in any circumstances whatsoever, nuclear armed politicians would actually fire these weapons?
The answer to this is negative. There could be a confluence of political tension, military engagement, and technical breakdown in the early warning systems that could persuade one or other of the nuclear powers that an attack was under way. In which case a general nuclear holocaust would ensue, which would almost certainly bring an end to human civilisation.
If the consequence of breakdown of a system is infinitely destructive, you employ that system if and only if the possibility of its breakdown is zero.
Since the possibility of breakdown of deterrence is greater than zero, we must disable and dismantle all nuclear weapons.