Reader Helen DeWitt writes in with the following description of the U.S. military’s current system of officer promotion, as told to her by an Air Force officer who just returned from Baghdad:

Officers rise through the system without relevance to merit; promotions are based on the length of time the officer has been in the system. (Up to the rank of Lieutenant-Colonel, anyway — to make Colonel you have to have done more than serve time.) Enlisted men are subject to a completely different rule: you see them studying for months, mastering the contents of a book this thick (makes gesture, thumb and fingers about three inches apart).

To be an officer you must either have been to one of the military academies or to college. Because promotion is not based on merit, smart officers get frustrated and leave for jobs where they can make better money; less able officers have every reason to stay, since incompetence is no impediment to career advancement. Since the effect of the system is to retain the least able, it perpetuates the elimination of the able: the norm is for smart young officers to find themselves reporting not to superiors like themselves (the ablest left early in frustration at the stupidity of the system), but to superiors who a) were not frustrated by the system and b) feel threatened by clever subordinates … And that’s how we get the leadership of our defense services.