Back to North and South (Korea, that is)

I was initially troubled by a post on Eschaton(Atrios) by Lambert tonight. I'm not so sure about this, though. Here's the quote from military.com:

The U.S. is now moving rapidly to relocate its forces in South Korea well to the south of the DMZ. I suspect the real reason is to move them out of range of North Korean artillery. At present, if we launch airstrikes on North Korea, Pyongyang can respond with a massive, World War I-style artillery bombardment of U.S. ground troops that could kill thousands. The sudden withdrawal of Americans to positions south of the Han river reveals our intention to go after North Korea's nuclear and missile facilities. A possible North Korean riposte: demand Japan expel all American forces or kiss Osaka goodbye.

I just don't buy it. As our troops are withdrawn from the DMZ, our troops are replaced by ROK (Republic of Korea, aka South Korea) army troops. We wouldn't pull back, to leave them as obvious cannon-fodder. More likely, we are pulling back as part of a complex geopolitical charade.

When the Korean Armistace was signed, there were three parties. North Korea, China, and the U.S. The South Korean goverment was not involved and did not sign the armistace. This is why the North Koreans demand to have peace talks with the U.S., bypassing the South Koreans. This is why the U.S. is withdrawing its troops. Once they no longer patrol the border, they are no longer a threat to the North, and no longer need be a party to peace talks.

To maintain geopolitical stability, they can do as good a job in Osan, but without the direct threat on the North. And, the U.S. war plan for the penninsula already plans on losing the DMZ and Seoul, so why keep troops there anyway? Yongsan Army Base is on prime Seoul real estate.