This posturing is no doubt coming from the recent change in leadership of North Korea. It is true that since that chap took charge they have once again begun work on long range intercontinental ballistic missiles.
Is Korea likely to attack the United States, absolutely not in a direct nuclear manner. I do not think that China would tollerate it, and I do not believe that it could be successful with the US Starwars programme in action.
Will North Korea attack South Korea...that is the danger in this situation. Personally...if the North Koreans lack the Chinese support, I dont think they would dare.
China is unusually linient to these small pockets of despotism in the south regions of Asia, they tollerate Mynmar, they tollerate North Korea...but it is a tolleration. China is like an elephant that could almost roll over in her sleep and squash these countries and their regiemes
To hear China calling for sanctions is an indicator that we are probably safe in terms of North Korea.
If North Korea does attack the South, it will be with a similar effect to Iran attacking Israel...the target is not the direct strike, but the hope that the retaliation will involve the United States and legitamate a justification in the eyes of the offender that they can then attack the US.
Thats why they wouldnt attack Israel or South Korea with nuclear weapons...they will save the nuclear weapons for attacking the US when, they hope, the US responds on behalf of south korea and/or Israel.
In the case of South Korea, I dont think we even need to worry about Missile attacks. If the North plans to wage war on the South it will be a full scale land invasion not a bombardment campaign. South Korea is isolated by the ocean. If the Americans or Japanese didnt get there in time, it would be a dunkirk situation where the southern koreans would be driven south right into the ocean.
However...I have got to say, I do think that its foolish for the South Koreans to do a military display infront of the North Koreans, whilst not an act of war, it certainly is a bit distasteful to parade your military infront of a people who really destest you...if anything is going to piss them off unneedfully, it would be that.
I dont know if the US has fortified South Korea enough to hold the peninsular, neither do I know how long/how close reinforcements might be. We dont know how quickly or how good the North Koreans actually are. They may have a lot of people...but, they dont really do anything but prance around...I'm not really thinking that they have combat expeirience. They are kinda untested recently.