Interestingly -- perhaps you know this already -- the US military keeps a strict segregation between Peace Corps and the military: If you join one, you are forever-banned from joining the other. I'm not sure about the historical reasoning for it, though. Something else interesting: One of my childhood friends joined the Peace Corps, and wherever he went (in Africa), those countries always accused Peace Corps members of being CIA operatives. He was always super defensive about there being no CIA operatives in the Peace Corps, which in its own way was kind of suspicious.