To a certain degree, if the military was an indoctrination method, it failed miserably. I was in the Marine Corps for four years and can say with absolute certainty that the services are direct cross section of society, faults and all. There was no "Hail government" mentality in there. The majority of people I knew thought our politicians were just as retarded as civilians do.
This is something I've noticed repeatedly in my adult years. Military, and ex-military, people are among the staunchest libertarians I know, which runs counter the assumptions I had coming out of high school. It seems to be further substantiated by the overwhelming preference for Ron Paul among military members - at least those who make political contributions.
I think it's because military personnel are at the front of our foreign affairs, and that they live a totalitarian lifestyle during their service. They've lived and seen what the country, and these armchair generals, are completely ignorant about.
Example. I was still in the service on 9/11, I was eating breakfast when the news starting rolling in. I witnessed several Marines begin to freak out when the reality of war hit them. Granted, they knew that war was a possibility when they signed up, but the actual reality of it scared them more than they were prepared for. Being in the military during at that time gave them a very realistic outlook of the situation, beyond the emotional reactionary of REVENGE!
And during the Iraq war, they weren't swayed by all of the bullshit "We wanna win" that conservatives were spewing. Being in the middle of that culture showed them that that part of world is pretty much beyond hope. Tribal wars will not stop because we kick one tyrant out of power. They wanted to come home. Even a buddy of mine who was pressuring me to re-enlist and go to Iraq changed his tune once he got there. I still remember the email "Don't come over here, it fucking sucks".
Then there's PTSD. My wife is a CNA and tells me stories of residents (names withheld of course) who wake up in the middle of the night screaming because they think they're still in the middle of the war.
I can totally believe that more servicemen are libertarian. They know better than anyone everything that goes in, and comes out, of a war are nowhere near worth stopping a
potential threat or nation building. They don't give a shit about the politics of foreign affairs, they care about their life and the life of their family. And if it can't be proven beyond a shadow of a doubt that there is a threat, then fuck it.