In my experience, once most of them made O-5 (Lt. Colonel, Commander, etc) they became political officers. In Baghdad, these were the officers that were dealing with the contractors and working mostly at desks. These people tended to really wrench up the works trying to get things done. I'm sure there were some out in the field doing real soldier work, but there were so many command rank officers and GS civilian equivalents mucking about in the IZ that we struggled to get anything done with them. Think of Everett McGill's character (I know he was a Major, but he was obviously bucking for a promotion) in Heartbreak Ridge and you get a good idea of the kind of crap we had to deal with. I don't consider that regular army. Real GI's worked to solve problems. Command staff seemed hell-bent on making as many as possible. They couldn't make one decision on their feet. That's not a way to fight any battle.
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The ultimate result of shielding men from the effects of folly is to fill the world with fools.
-- Herbert Spencer, English Philosopher (1820-1903)