It is a practical problem. The military has an extremely long institutional memory and has perfected the process of mental conditioning over hundreds of years, to the point where 18 year olds can be given the power to kill and dropped into situations with little to no supervision - and it generally doesn't result in an x-rated version of Lord of the Flies. The methods that the military uses to accomplish this would not work for police without a costly tear down and slow rebuild. The list of methods is far too long to list here, but they include a culture of self policing enabled by a meaningful shared experience (basic redefinition of family), and a mythology that requires a carefully managed narrative of history (Gen MacArthur's farewell address at West Point is full of examples).
It is a practical problem. The military has an extremely long institutional memory and has perfected the process of mental conditioning over hundreds of years, to the point where 18 year olds can be given the power to kill and dropped into situations with little to no supervision - and it generally doesn't result in an x-rated version of Lord of the Flies. The methods that the military uses to accomplish this would not work for police without a costly tear down and slow rebuild. The list of methods is far too long to list here, but they include a culture of self policing enabled by a meaningful shared experience (basic redefinition of family), and a mythology that requires a carefully managed narrative of history (Gen MacArthur's farewell address at West Point is full of examples).