I can't agree with the idea that diplomaccy will do anything positive. We know what type of character Kim has shown himself to be. He is ruthless, a killer of kin and friends. He can't be trusted to act with Judeo-Christian, or western values. To negotiate with him simply gives him legitimacy in his eyes, a trump card that the west is weak. It would only embolden him to carry on as he has been, likely with even more impunity. He wants power internationally just as he has exerted within his country.

A man will not change his ways unless he experiences a severe traumatic event. That event is not likely to come from within his country. That leaves only externally sourced events. That event won't come until Kim oversteps internationlly based boundaries, and he's moving toward conflict at a measured pace. The time will come and the world can expect it. I suspect Putin gave N.K. weapons technology. Kim may be Putin's puppet, emboldening him even more. Putin will push NK when Putin is ready.