NK needs to be stopped they are prepping for nuclear war mark my words. look how happy they are when doing nuclear tests!
And how do you "suggest" to stop them?, this is not the same case as a defenseless Japan with no nuclear armory, NK is a nation capable of building more powerful nuclear bombs as time passes, in 2006 when NK conducted its first Nuclear Bomb test, it only had a power of 0.7 Kilotons so while many governments were openly criticizing NK for its acts, nobody did nothing.
They underestimated NK, and look at how far they got, their last nuclear test had a power of 20 to 30 kilotons, and is not even clear if that is the full power of its nuclear armory capacity, many governments have tried to convince NK to "denuclearize" its country, but you think Kim Jong Un is gonna stop his nuclear research?, yeah, of course, that's like convincing us citizens to go full soviet communist, not gonna happen.
Not only is a nation capable of having a comeback in case of any militar menace either from SK or the US, they also have ties with the chinese and russian governments, and no sane country wants to fuck with either of them, in the end, all the countries that wants to try to "stop" NK are in Check, the only hope, as i mean, only hope to denuclearize NK is if the citizens from the country start a coup d'état to overthrow Kim's government.
But with so many problems around its citizens, which includes climate, corruption, no freedom of speech, etc. do you seriously think the people from there are gonna start rebelling against the guy who has nuclear weapons and control over one of the biggest military personnel in the world?, Kings from medieval times were easier to overthrow than modern North Korea, so only if in the weird case Kim Jong Un and all of his relatives suddenly died by a heart attack, then you would have the case resolved.
But that's not the case, so whatever whatevers, point in case, stopping NK is like trying to beat NES Silver Surfer blindfolded with ear-plugs using the roll'n'rocker, and i think doing the last is easier.