Well I see it this way.
North Korea is behaving aggressively because of its huge supporter China, but now China is realising their pet has gotten off its leash and now they are denouncing them. Why not invade and take back control? I'm sure the US and all its firepower would enjoy the help while this Iraq debacle continues. No the Chinese are Either
A. Secretly supporting the NK forces in their anti US stance OR
B. Are really PO'ed but won't do stuff all because even if the NK nuclear program is primitive it is confirmed that they have nuclear weapons, as crappy as these may be they are WELL within range of China and in turn the Chinese are scared shiczeless.
Either the peoples republic of North Korea will collapse and we will enter to establish order and democracy ( If we beat the Chinese to the punch) or they will start WW3 and commit suicide.
Now we have backed the SKs to the hilt and have armed them with every possible means at our disposal not to mention our own task forces in the area so its unlikely that the NKs will invade unless of course out of desperation. The UN cannot do anything besides impose embargo's and the like, this is FORCING us into war and they must know it. NK relies on trade for its food, without it they are sunk and they know it, food ,oil and rawmaterials, all things NK has to trade for to get. this in turn will force them to invade SK to seize our assets and start a war involving us and possibly China and the Russian federation, I don't think china will let their favourite minion die.
To sum up NK will almost certainly start a war if we continue on the path we are following
I just
that it does not come to that