Pablo, who started this thread four years ago, and John Hardley, are understandably confused by the date 1942, but McGrath is right. Seeger wrote and copyrighted it in 1967; his subject Vietnam. Lighter is right about the event that probably inspired Seeger.

I "think" I remember an earlier, similar event about the time I entered the Army in 1942, but I may be confused about that. It was a long time ago.