A little reality check here:
First; the UNhas the right to sanction any nation, member or not, that expects the rest of the world to play by their rules. The only reason the UN tends to leave the US alone is that we supplied not only their headquarters, but the lion share of the funds they use when they decide to act in the world; I.E, sending UN troops to the Ivory Coast required the US to supply the transport for both men and supplies.
North Korea has been pushing for over two generations that the only reason they lost the Great Patriotic War (What we call the Korean War) was that those horrible Americans stopped them. Logical in that the US footed the bill for everything but the pay for the actual soldiers. However they didn't lose that war because the Communist Chinese footed the bill for them to the tune of 2.5 million troops after Inchon, not to mention supplying them with every material need and bases for supply and fighter aircraft above the Yalu river.
One person said in a rather acrimonious argument that the reason for the non proliferation treaty was because we didn't want other nations to have the same toys we have. However hey ignored the fact that every nation that has deployed nukes has put us at the point where we're dependent on the least stable leader in those countries for peace. Saturday Night Live joked about it when they did a sketch about Nixon before he resigned and Kissinger told him they'd disabled his launch button.
Now, developing a nuke is child's play. You can find 90% of the specifics and designs online. All you need is two additional things; fissionable materials, which Korea pruduces themselves, and a delivery system, unless you intend to have the US mail deliver it for you. That is why both NK and Iran deciding they wanted to build processing centers for their spent fuel rods was the first indicator we had that they intended such a goal.Their building a processing facility is like you or I building a factory to manufacture parts just for your car. you don't do it unless it cannot be done elsewhere.
That is why the Schrub as my Ex called the Second Bush named Korea as a member of his 'Axis of Evil'. Korea has the uranium, Iraq had the delivery system, albeit short ranged. His threat then to Korea, as much as the liberal press labasted him was a repat of Kennedy's threat to Cuba; if a nuke hits anyone fired from Iraq or any nation backing terrorusts, we'll hold you personally responsible.
As for delivery systems, the Koreans do not have the range to hit DC, which is good in a way. However they can hit major Naval bases of the US in the Pacific along with Alaska and the West Coast. To have the quantum leap of hitting DC would be like Zimbabwe designing a missile in 2002 and claiming they now field a missile capable of hitting Europe. Without technical assistance from outside, it doesn't happen.
Item last, even assuming worst case scenarios where they began processing immediately after they reopened their nuclear plant in 2002, they do not have enough weapons to really matter on the worlds stage. It would be like a street gang here locally in Las Vegas threatening to destroy Metro PD. They could get a few licks in, then every nation around them with nukes would be telling them to surrender now, or face obliteration.
Probable losses, Kadena Okinawa, Pearl Harbor, Seattle or San Francisco on our end. On theirs?
As my ex would have said, we'd turn the country into a parking lot, and let the survivors paint the lines.
And it wouldn't be just US missiles hitting them.