Nuclear weapons on the Korean penninsula pose an immediate danger to the international community. North Korea (The DPRK) could use a nuclear weapon against a strategic American ally (Japan) or it could sell WMD on the black market. Furthermore, its possession of a viable nuclear weapons program could encourage nuclear proliferation in South Asia.
North Korean nukes are a serious symptom of a larger problem, namely that the DPRK is a failed state. Pyongyang routinely engages in counterfeiting and drug smuggling (as well as egregious human rights abuses), and kidnapping. Appropriately, North Korea is often referred to as "the hermit kingdom" because its policies isolate its citizens both internally and externally a la Stalinist-style repression.
North Korea could change its behavior, though how easily (politically and practically) is unclear. DPRK force concentration along the DMZ is astronomical; the military receives something like 8-10 percent of GDP. Central planning only drives the economy farther into the ground. Therefore, I think Michael E. O'Hanlon is correct that any resolution of the nuclear crisis should begin with measures that both curtail the economic incetive to produce nuclear weapons and encourage economic reform. For example, a reduction in North and South Korean force concentration along the DMZ could redirect government outlays towards the purchase of foodstuffs, something the starving population of North Korea desperately needs.
My point is this: placing the North Korean nuclear crisis squarely in the context of a failed state might increase the breadth and effectiveness of potential diplomatic solutions.