You can say the soldier is nothing without all the rest of the infrastructure. Still, since the soldier is the one who takes the most risk of personal harm or death, its easier to imagine replacing any of the other jobs in the larger scheme of things. If everyone in your group decides its too risky to be a soldier, you are vulnerable to another group which thinks differently.
Guess that's the obvious part, how it is a rationality quote I'm not sure. Maybe its rational to put soldiers in a special and revered category given how important they are, for now at least.
"You can only compromise your principles once. After then you don't have any."
-- Smug Lisp Weeny
"If you want to do good, work on the technology, not on getting power."
-- John McCarthy
"If you’re interested in being on the right side of disputes, you will refute your opponents’ arguments. But if you’re interested in producing truth, you will fix your opponents’ arguments for them. To win, you must fight not only the creature you encounter; you must fight the most horrible thing that can be constructed from its corpse."
-- Black Belt Bayesian
"I normally thought of "God!" as a disclaimer, or like the MPAA rating you see just before a movie starts: it told me before I continued into conversation with that person, that that person had limitations to their intellectual capacity or intellectual honesty."
-- Mike Barskey
"It is the soldier, not the reporter, who has given us freedom of the press. It is the soldier, not the poet, who has given us freedom of speech. It is the soldier, not the campus organizer, who has given us the freedom to demonstrate. It is the soldier, not the lawyer, who has given us the right to a fair trial. It is the soldier, who salutes the flag, who serves under the flag, and whose coffin is draped by the flag, who allows the protester to burn the flag."
-- Father Dennis Edward O'Brien, USMC