North Korea would be mad to disarm, page-21

The US has in South Korea, nuclear weapons, a standing air force, + troops.  It has an aircraft carrier fleet nearby. It also has annual military training "invasion exercises" which are timed to coincide with NK rice harvest time (just when NK needs to use its own troops to help out with harvesting). 

The very recent discovery by China of substantial light crude and gas fields in the Bohai sea (an offshoot of the yellow sea) dramatically changes the prospects for more oil and gas finds in that area. China now has a huge incentive to increase the transport, commercial and military alliances with NK, and to provide a greater naval presence in the South China Sea.

North Korea knows that if it ever used nuclear weapons, it could kiss its entire population good bye, so they have the "ultimate" but useless deterrent. It is a bit like saying to the US  … "If you beat me up and rob me, I will pull the pin on this grenade". - stupid diplomacy. For its own sake NK needs an alliance with China.

Bear in mind that North Korea has a national indelible memory of the "Korean war" (which I guess the NKs call the "American war"). They had every single town bombed, their food crops entirely destroyed by US bombing (yes the US used defoliants), and their dams destroyed. The only reason the population survived was because of a major food relief provided by China and Russia at the time.  NK is fully aware that in any future conflict from the US they would be treated in the same way that Vietnam was treated. Vietnamese children are still being born with deformities caused by the dioxin that the US wilfully used.
Q: Why the "Vietnam war"? 
A: Because the US even back then KNEW of the oil significance and the strategic importance to control the South China Sea. The "domino theory" was smoke.

North and South Korea wanted to re-establish commercial relations with each other, and even planned to develop a rail connection and a highway from South Korea to North Korea.  The US stopped this by saying that the rail line and the highway was not going through the demilitarized zone.

So
Q: Who "owns" the political future of South Korea?
A: The US

North Korea could make an offer to China: "We will remove all our nuclear weapons provided China provides us with comprehensive military protection, including Chinese military bases in NK.
In return we will introduce
a) a more representative political system
b) strong encouragement for Chinese investment in NK manufacturing and resources
c) plans for strong mutual mutual economic co-operation, using the yuan as currency.

Curiously there is terrain in what is now China, that historically used to be part of NK. These ethnic Koreans now proudly call themselves "Chinese nationalists" and they see the contrast of standards of living between China and NK.

The question is "Will Kim allow the NK to progress, at the cost of him losing his family fiefdom?

The world is becoming more divided between "the west" and "the rest".
I have had my rant now.