This is China's problem much more than it is the US's problem. It is also a bigger problem for South Korea and Japan.
NK is close to all the other countries and could use their nukes as well as their much more numerous conventional weapons on them as well.
The Russians share a border with N.Korea, and the US does not, so it's probably a bigger problem for them, although that part of Russia is not heavily populated nor economically significant.
China and S. Korea together could probably pull off some sort of coup if they could enlist the aid of the NK Army.
The CIA and other US intel services have proven to be a collection of overpaid, incompetent, blundering sycophants, if for no other reason than they only reach conclusions that agree with the incompetent, blundering assortment of warmongering assholes that include Juniorbush, Cheney, Rice, Rummy and Negroponte.
I imagine that there may be a few knowledgeable officials in US Intel that need to be heard. The US does have a sizeable number of Korean Americans and has every reason, after 55 years of occupation bases in SK, to know more about NK than it did about Iraq, after all. The problem would be getting the voices of these competent intel people heard over the sound of the water gently slapping up against John Negroponte's ample flab as he spends his days in some sort of hot tub, I hear.
Krauthammer is clearly nuts, but could be useful to spew disinformation.
As Andy Rooney said, a sane NK citizen might consider it entirely useful for his country to have nuclear weapons, as a deterrent. It is more logical for Kim to claim that he is protecting his people with a nuclear program than it is for Juniorbush to claim that invading Iraq was necessary to protect the US, which it clearly wasn't.
It is ideal from any country's point of view, that it have a bigger army and better weapons than any conceivable enemy. But this is not possible: everyone cannot have the biggest army and the best weapons.
It would be better for the people of every country if NO ONE had any nukes at all.