Here are some sources you should try reading. You may find them interesting.
http://www.mtholyoke.edu/acad/intrel/vietnam.htm
Being at the tail end of that affair myself and having many friends who were involved at all levels in all of the countries involved from beginning to well after the official
end, it is much more complicated than you can imagine...and for many good reasons.
My father used to tell me that if I had a question for Mr Ed (the talking horse of television), I should go to the end with the teeth.
Also, you speak of SACSA in your remarks - FYI - SACSA was BG Don Blackburn, the first Chief-MACVSOG, not some bureaucrat, and carried enormous influence in the Pentagon. I think that BG Blackburn had a good idea of just what was intended, what was happening, and who was involved.
Richard