One thing allot of people are forgetting about nukes is they can be intercepted nowadays. Beforehand around cold war era they were terrifying because they were usually carried on high flying planes that were near impossible to intercept. If a country decided they'd want you nuked, you were forgeted. Your only defense was threatening to simultaneously nuke them to get them to back off.
Nowadays we have loving multiple-acquisition laser defense systems mounted to Boeing sized planes and soon, even fighter jets. Not counting that missile technology has progressed allot and it is possible in many ways to intercept an ICBM. If a rebel state like North Korea fires a nuke off it will probably rain back on them in the form of shrapnel and fallout by the time it reaches the stratosphere. Whenever North Korea does complete and ready it's own ICBMs the rest of the world would probably be packing matter/antimatter bombs and singularity warheads by then.