[geoschmo]

The US has no military options, and frankly NK knows this or they wouldn't have taken this step. We've been bled dry in Iraq and Afghanistan. Our reserves in manpower and materiel have been depleted to the point where I'm not even sure we could sustain a long term conventional air campaign. Our only option that will have any effect is the tacNukes and that has political side effects which are incalculable.

As distastful as it sounds, I think we've reached the point where the only military option, if we think the non-military options are gone, is to basically give China a permission slip to annex North Korea. North Korea survives at their pleasure as it is now. I can't imagine the people of North Korea could be any worse off as an official part of China than they are now.

Edit: Of course this assumes that China would be interested in taking such action. My gut tells me they might if they had assurances from the international community there would be no repercussions.