I think the main point here is that while faulty intel is always a risk, the biggest problem is willful misinterpretation. For how things played out in Vietnam,

I think the main point here is that while faulty intel is always a risk, the biggest problem is willful misinterpretation. For how things played out in Vietnam, Frank Snepp's book seems to be the most well known, perhaps because it came out early. A more forceful account and criticism by a CIA field analyst is Sam Adam's War of Numbers (1995). (https://www.goodreads.com/book/show/2471957.War_Of_Numbers https://www.goodreads.com/book/show/2471957.War_Of_Numbers)