I think it's mostly due to their nuclear program being successful at producing an H-Bomb as well as a warhead. People here say their nuclear program is a failu

I think it's mostly due to their nuclear program being successful at producing an H-Bomb as well as a warhead. People here say their nuclear program is a failutre, but they already tested the H-bomb as working, and it does look like it can fit in a warhead: http://s.newsweek.com/sites/www.newsweek.com/files/styles/lg/public/2017/10/25/1025kimjongunnorthkoreahydrogenbomb.jpg http://s.newsweek.com/sites/www.newsweek.com/files/styles/lg... They probably feel they're in a strong enough negotiating position now to resume six-party talks: https://en.wikipedia.org/wiki/Six-party_talks https://en.wikipedia.org/wiki/Six-party_talks