Why didn't South Korea start, decades ago, relocating its capital to somewhere out of artillery fire, i.e. end all development in Seoul and build a new city in the south. It seems to be a bit thoughtless to build a major city where it is a hostage to the brutal and aggressive dictatorship next door.
http://en.wikipedia.org/wiki/Washington,_D.C._in_the_America...
Despite being the nation's capital, Washington remained a small city of a few thousand residents, virtually deserted during the torrid summertime, until the outbreak of the Civil War.
"Of all the detestable places Washington is first. Crowd, heat, bad quarters, bad fair [fare], bad smells, mosquitos, and a plague of flies transcending everything within my experience... Beelzebub surely reigns here, and Willard's Hotel is his temple."
At the outset the U.S. Civil War, Washington D.C. wasn't just a stinking, festering, undefended podunk backwater; it was a stinking, festering, undefended podunk backwater bordered on the south by the most powerful bastion of Confederate sentiment and on the north by a state experiencing a crisis of North/South identity. So why didn't Lincoln pack up and move the capital to Philadelphia or New York? This question isn't rhetorical, I'm genuinely curious. Was it national pride? Would moving the capital have been viewed as an act of implicit defeat? Whatever the reason, perhaps the South Koreans felt the same.
It is easy to find lots of information on Washington DC's civil war defenses - some ~70 forts, 400 emplacements for field guns, and unmatched transportation/communication infrastructure. The resources devoted to protecting the capital instead of campaigning were a regular source of contention for Lincoln, his generals, and public opinion - many opportunities were missed by Army of the Potomac commanders who feared leaving DC vulnerable.
On the other side, the Confederate capital was originally in Montgomery, Alabama, and moved to Richmond, Virginia when Virginia seceded following Fort Sumter. Like Washington, this put the capital remarkably close to the front lines, but the existing industry, infrastructure, political weight, and defensibility seemed to make the position worth the risk.
Hoping someone with knowledge chimes in :).
During the war construction costs for the new dome [for the Capitol building] other parts of the building drew unfavorable remarks. Lincoln, however, stressed the importance of continuing the work, saying, "If people see the Capitol going on, it is a sign we intend the Union shall go on."
The same reasoning would explain keeping the capital in DC.
http://www.bbc.co.uk/news/world-asia-18670195
I don't follow Korean politics, so I don't know if the motivations were to escape NK artillery or some other reason, but it seems like organizing a massive move is just one of those things democracy is bad at.
They took traditions seriously and traditionally it's THE capital. Even North Korea considered Seoul the capital for decades, calling Pyongyang "the capital of revolution" or something like that.
Also, it was a very poor and unstable country post-war and didn't feature much strategic thinking. And obviously USA wanted their military bases near the border, i.e. in Seoul.
Also, an attempt to move people out of the capital would have been a provocative act to North Korea, at any time. Because it would have been seen as an obvious prelude to an invasion.
However, even if all of Seoul was evacuated it wouldn't necessarily make things so much better as North Korea has missiles with enough range even to hit Japan or the US, and potentially nuclear weapons to go with them. Potentially one could imagine banking on anti-missile systems to nullify that threat but that's a pretty big gamble.
It's prohibitively expensive to move a city, especially if the justification is "if we get really f-d, then we'll be a little less f-d".
The U.S.'s defense against an attack on D.C. was the assumption of a rational enemy, nuclear hardened command and control bunkers very far from shore, nuclear hardened ICBM silos very far from shore, continuously airborne nuclear bombers, and very stealthy SSBNs.
Really, South Korea's strongest defense is that an invasion by the North would instantly kill enough US troops to guarantee massive US retaliation against all military bases in NK, and would instantly kill enough civilians that China wouldn't retaliate as long as no US troops crossed the DMZ. Hopefully this is a big enough threat that a significant number of high-level and mid-level military leaders would stage a coup d'etat rather than follow orders to invade SK.
Edit: one would hope that the U.S. and China already have negotiated how much retaliation China will tolerate in response to various acts of war by NK. One would also hope that these details have been leaked to NK.
Maybe submit this to xkcd's 'what-if'?