Sorry, I think I was incorrect about Pepper: he actually served in the US Army in World War II, and the "cocktails" he described may have been designed to mislead parole boards about heroin use.
Re. the other point, many many American novels, particularly from the Vietnam era, described leading characters' efforts to obtain 4F exemptions, thus avoiding wartime service.
I'll check my shelves to see if I have any quotable novels around...