Well, damn. I wasn't able to view this page on the ciao site, but could access it through a google search. Now I can't access it at all, and I bet no one else can either. If you want a copy of this just leave a comment.
I just found an essay called 'The United States and South Korean Democratization', by James Fowler, which was published in Political Science Quarterly in 1999.
I haven't had a chance to read it in its entirety, but it examines the US role in the pro-democracy movements of 1979-80 and 1987. He uses the declassified 'Cherokee' files (the same ones Tim Shorrock used), but actually cites each document. From what I've read so far it's a pretty balanced look at the US role, and his examination of America's application of public and 'private' pressure on the Park and Chun regimes is a useful one. My main criticism so far would be that he seems to rely too much on the cables for accounts of events in Korea (like the Busan-Masan and Kwangju uprisings) and gets certain details and dates wrong. Despite this, I think it certainly falls into the 'Required Reading' category.