The timing sounds like he was being groomed for a political career, and a tour in VN was a necessary "ticket punch" for that career. His bio lists him as being a captain in '59. Haven't seen what rank he was in '66, but I don't think he was leading from the front by that point
I would be curious as to his family history
Murtha was in the Reserves for a long while, then volunteers to go to Nam in '66-67, gets a few decorations, then gets elected to the Pennsylvania house in the 68 elections.
Then over the next 23 years he never receives has a significant deployment or receives another award until his DSM kiss at his retirement in 1990? Hmmmmmmm.......
I'll just throw out that he said tonight, on 60 minutes, he quit college to volunteer for 'Nam and he made exemplary mention of how his mother cried....