1. May have nukes.
2. Militaristic totalitarian state.
3. Nutty, bad-haired leader.
4. Huge, well-trained standing army.
5. No direct strategic importance to the USA.

I wouldn't do military intervention against them unless I was willing to go nuke early and often. #5 argues against that. However, if NK gets the launch and guidance system for its 3-stage missle reliable enough to hit Anchorage, Seattle, Portland, S.F., L.A., and San Diego, I suspect senators and congressmen from those states would suddenly discover the many virtues of SDI.