Wow, that's an option I hadn't even considered due to North Korea's closely watched borders. I guess it's hard to imagine a terrorist style nuclear strike from NK.
You have to understand that there is more to NK than just what we hear on the news. They're at the center of a lot of illegal activity in the Asian/Pacific region, and have a state-sponsored investment in criminal infrastructure (drugs, smuggling, kidnapping) that they use to keep themselves propped up.