One thing is clear above all: countries which have nuclear weapons or the capacity to build them do well to never, ever give up that capacity no matter which promises are made in return for such a move. This does not bode well for attempts at non-proliferation and it is likely that the number of 'nuclear powers' will only grow, not diminish. If Ukraine had not given up its nukes it is doubtful whether Russia would have invaded, even if it remains unclear whether Ukraine could actually have used the devices.