I favor a draw-of US forces on the Korean penninsula because our presence serves as an assurance policy for the ROK when the South is certainly capable of defending itself from the North (the South's economy is 24 times the size of the North's--a magnitude almost identical to the US-Iranian gap (both in PPP terms)). If Kim Jung Il was dumb enough to launch a conventional attack on the South he would be routed. Although North Korea has a standing army of over a million men, its military equipment is mostly from the Korean War era (T-55 and T-56 tanks) and estimated to be significantly under-functioning.
There are reports from those formerly having lived in the North that military vehicles are often found rusting on roadsides and that ammunition isn't used during training exercises because the military has such a limited supply. The soldiers don't get real practice and the country is shockingly malnourished, with a populous that is over half a foot shorter than their brethren in the South.
The North's air power, which is relatively advanced, suffers from a lack of experienced pilots (due to fuel shortages, North Korean pilots only get 10 hours of in-flight training each year compared to several hundred hours in the US).
The footage reels of massive soldier marches in the North create a sense of enormity, but my gut tells me that if a conflict were to break out, the North would quickly be revealed as a paper tiger. The North's annual military spending amounts to $5 billion, while the South spends $21 billion. The South has twice as many people fit for service as does the North. And of course the North, with a PPP of $1700 (as well off as Haiti), has no ability to sustain a military campaign of any duration (I imagine tanks running out of fuel as they push across the DMZ and have to be abandoned).
The biggest threat comes from the artillery aimed at South Korean cities, with several hundred pointed at Seoul, and WMD capabilities. The North has all kinds of nasty stuff from mustard gas to uranium bombs. But there is little 30,000 American soldiers within range of these devices would be able to do to halt a massive barrage if the North let loose. Retaliation in-kind would have to be the response if Kim Song Il, who so loves the life's hedonistic pleasures, was so suicidal.
South Korea was on the road to nuclear weapons in the seventies, but the US applied pressure and it stopped. The North's only way to best the South is through the use of the nuclear weapons it has that the South does not. Let's speed up the removal of an American presence (slated to decrease by 5,000 by 2008) and allow South Korea (as well as Japan, which has an acrimonious relationship with Korea, especially the North) to go nuclear. Currently our personnel is little more than potential WMD fodder. The ruling liberals want us out anyway. Why not oblige them?