When a nation fights a series of long, low-intensity wars, soldiers are expected to act like cops and in time, cops act like soldiers.
The cops and soldiers will have NO PROBLEM shooting at us.
Many of them come fro places where it is very natural for troops to be used in policing roles.
Some might even enjoy it.
Try to imagine being one of these soldiers or cops on constant guard duty, no matter where he is (the mess hall, barracks, even on leave). Imagine looking at every man, woman and child and wondering if they’re going to pull a gun or throw a grenade. Imagine wondering if every bite of food or sip of drink could be poisoned or have crushed glass in it?
THAT is why partisan warfare is the nightmare of regular soldiers.
http://www.youtube.com/watch?v=AfeWglkjxW0
In the event of a civil war it won’t take very long before being a cop in uniform or driving a cop car would make you a target for the nearest sniper.