I thought the biggest problem with Seoul was that it was within artillery range. Iron Dome and the like won't help much with that (even if it does work, which is debatable)...

There's lots of drawings and speculation on NK hardware and tactics here (from 2009) - http://www.militaryp...rikes!-%282009%29

A major military conflict with NK would be a disaster. As you say, sure, we would "win", but what comes after? The Koreans are one big family, but the northern half is filled with Starving Crazy Uncles. Once hostilities end, or maybe even once hostilities start, millions will want to try to leave. (I think that's probably the main reason why China apparently is working on the border - they don't want people thinking about running across the first chance they get.) We can break NK's military infrastructure from the air (but how quickly? Quick enough to prevent Seoul from being flattened??). We can destroy their electronic communications. But what about at the unit level? We don't want to be on the ground above the 38th Parallel, but if we destroy their leadership and infrastructure someone has to be. Are we willing to let the South run things by themselves? Are they willing and able to? "Land war in Asia" is something that we must always have in our minds...

China and Russia have had a red line about "external interference" for decades. It seems to me that something really big would have to happen before they changed their mind about that, and even then, they may require conditions for any assent (or lack of assistance to the other side). If the US and the South look to be "winning" (or winning too easily), they may feel the need to help prop-up the North (e.g. agreeing to a change in leadership but no defeat by the US and the South - but how could that work given the cult of personality and history there?). It's something that has to be considered.

There are lots of ramifications.

I don't think Kim and his generals want to start a war, but I do suspect that they want a small battle to illustrate that they're serious and important and need to be treated with deference. The Kims seem to have to prove themselves, and seemingly the only way they can do so is with military equipment and arms. They apparently feel the need to ratchet things up after the sanctions were tightened. I have no special knowledge or insight, but I wouldn't be surprised if they decide to bombard or even take an island or sink another ship. I hope that we and the South are thinking seriously about how to respond to such a provocation. The US and SK need to be thinking a few moves ahead and not just responding to the immediate circumstances...

My $0.02.

Cheers,
Scott.