The idea that everyone should have nukes is a truly frightening idea. Maybe Japan but it should be tightly controlled to the extent possible.
However I believe nukes will become commonplace over time. It is extremely hard to stop it. Tough as Trump is I doubt he would invade NK to stop it. Trump is just waiting for NK to screw up so he can pounce but I think Fat Boy is smarter than he is given credit for and will be careful.
The only long term solution is to have an air-tight defensive shield for air-borne nukes and detection monitors and screening for anything coming into the country. That will be enormously expensive to implement but that is what will be needed to survive.
Anti-proliferation policy has teeth only strong enough to bite allies. Worse, those policy makers think that smile and bribe are the proper response to the worst offenders.