Is... this happening? I doubt it. Why?
One word: Libya.
Why didn't I give two words? Because there are too many variations on the spelling of "Muammar Gaddafi," and I didn't want to get into a whole, big thing about it.
Remember Saddam Hussein? At least we can agree on the spelling of his name. As of 1998, he had stockpiles of chemical and biological weapons. Then, he kicked out the UN weapons inspectors. Chemical and biological weapons, though, need to be maintained, and he didn't maintain them. He just wanted domestic insurgents and opponents in Iran to think he had those weapons so that he would be safe from revolt, but he figured that if we didn't have the physical evidence of the weapons, we wouldn't topple him. It was a shell game. It didn't work. In 2003, the Bush administration sent back in weapons inspectors, and Hussein played his shell game figuring that he could act shifty in order to keep the Iraqi Shi'ites convinced that he had enough to destroy them and prevent a revolt, but without physical evidence, he wouldn't get invaded. But, we invaded anyway.
In the aftermath, Gaddafi decided it was time to start playing nice. For a time, it looked like Bush's strategy would actually get the scumbags around the world to fall in line.
Ummm.... how'd that work out for him?
Supposedly, Kim Jong Un is willing to talk about giving up nuclear weapons. Don't get your hopes up. Basic deterrence: Kim knows that the only thing keeping him safe from attack is the fact that he has nukes, and his domestic political stability (yes, dictators have to worry about the threat of being toppled) comes from the perception that he is maintaining international strength.
If he gives up nukes, what happens? Two threats open up: threats of attack from outside, and threats of being toppled from within as he is seen to give up North Korea's strategic advantage.
What's going on? A few possibilities:
1) Kim Jong Un is going to start pulling a Lucy Van Pelt. Denuclearization is that football, taken away at the last minute just to fuck with us.
2) What's the demand? It could be something just too high for anyone to accept, in which case, see 1.
3) The ever-moving demand. See 1.
4) Count on Trump to screw it up by saying or doing something stupid.
5) This is all just bullshit.
OK, with that said, let's consider a few things. North Korea is dirt-poor. Their economic system isn't functional, international sanctions can work when imposed nearly worldwide...
I wrote that series a while back on "Political science & craziness." Trump is nuts. He might blow them up. Kim is rational. If he thinks Trump is crazier, there is a chance that he is backing down. There is a non-zero chance that this is legit, and a response to Trump being fucking nuts. Here's your obligatory link to Thomas Schelling's The Strategy of Conflict. If you can convince your adversary that you are crazy, and willing to carry out self-destructive threats, you have a bargaining advantage, and you can get people to give you things they wouldn't otherwise give you...
I may be linking back to that, and the "Political science & craziness" series, a lot soon. As Trump loves to say, "we'll see what happens."
Default, though? What happens is nothing. The strategic advantages of having nuclear weapons are too great to sacrifice, and Trump seems distracted right now by his trade war. At least those don't leave anything glowing in the dark.