Armed-forces personnel are trained to "engage and destroy," peace officers "to protect and to serve." Expecting young recruits to play both roles is expecting too much.
The soldiers' proverb that "it is better to be judged by 12 than carried by six" has recently gained new currency among American troops in Afghanistan. For combat soldiers, its meaning is clear: when in doubt, shoot first and ask questions later. While civilians may find this violent mindset shocking, it's important to recognize that we train our soldiers to, in the words of the U.S. Army's soldier's creed, "engage and destroy the enemies of the United States of America in close combat."
From its very inception, the Unites States military has defended American interests by threatening and, if required, committing violence. In basic training, drill instructors bellow the question, "What makes the green grass grow?", to which new recruits respond by screaming, "Blood -- bright red blood!" and stabbing a dummy in the guts with a bayonet. This is how we train our warriors and how we have done it for over 100 years.
We train our troops to kill, equip them with the world's most effective weapons, and send them to war. Yet in many instances, our leaders then ask these trained warriors to serve as peace officers, a job that involves entirely different expectations and holds them to a different standard. There are special subunits within the military whose members are trained to play both cop and commando, but the very nature of name "special" demonstrates that this is not normal training.