I have to give a lot of credit to Robert Kelly for trying to articulate both sides of the debate on this issue. Few authors, even academics, and certainly not pundits really try to argue both sides of an issue. Unfortunately , despite his best attempts, it is clear that Robert Kelly's retrenchment bias does show through but his arguments are an interesting read nonetheless. He never really articulates US interests and why it would be bad for there to be a war or catastrophic regime collapse on the peninsula.
Whether the US should stay or go is a perennial issue, that surprisingly, doesn't get discussed much. This is probably because if you really supported a US withdrawal, you would not be taken seriously in much of US or Korean foreign policy establishments.US foreign policy is dominated by a hawkish, interventionist consensus of neocons and liberal internationalists for whom the US positions in Japan and Korea have become ends in themselves as symbols of US hegemony (in neocon-speak, that's read as: 'global basing means we're f****** awesome!').
If he was really going to debate both sides of the issue he would have laid out the realist perspective on maintaining the ROK/US alliance which I think might be different than the hawkish, interventionist
consensus of neocons and liberal interventionists.
The irony is that the biggest proponent of retrenchment was Donald Rumsfeld. The entire OPCON transfer and relocation of US forces was his attempt to drive US forces from the peninsula. And although they do not know it or would not admit it all those in favor of the OPCON transfer are really in favor of US retrenchment and are just supporting Donald Rumsfeld's vision for the ROK/US alliance.