Could you expand on this? Perhaps naively, I would expect the US & allies to be able to bomb all NK military assets and topple the inferior government easily & quickly. It wouldn't be another guerilla ground war, we just want to destroy their military capabilities.
I guess there is still the concern that China would back NK, but I can't see what China benefits from that. A war with other superpowers to protect a poor, weak, unpredictable regime?