The US and North Korea seemed to be making progress before the Hanoi Summit took place. However, after the Hanoi talks fell apart, negotiations sputtered and then stalled. The situation now is arguably worse than it was three years ago. Professor Kyungyon Moon from Jeonbuk National University states that the US, rather than seeing North Korea as an equal negotiating partner, has instead sought to implement punishing tactics as though the regime is a “rogue boy” in need of discipline. This attitude on the part of the US has resulted in an unwillingness in Washington to consider further negotiations or compensatory measures. Professor Moon argues that while South Korea should be playing the role of active mediator between the two countries, it has not been able to keep North Korea and the US at the negotiation table. South Korea must do its part and actively mediate between North Korea and the US by convincing the US to provide a compensation mechanism to North Korea, which will open the path to resumed negotiations.
http://www.eai.or.kr/new/en/pub/view.asp?intSeq=20248&board=eng_issuebriefing