Im US Field Manual 19-15 gibt es Vorschriften, nach denen mit Waffengewalt gegen Demonstranten vorgegangen wird, genau so als ob es sich um gegnerische Truppen handelt:
Under extreme circumstances, U.S. military force may be turned against American civilians. An unusually explicit 1945 U.S. military field manual (pdf) described tactics for suppressing riots or protests when State and local officials are unable to control the situation.
“Domestic disturbances are manifestations of civil unrest or tension which take the
form of demonstrations or rioting. These public
demonstrations or riots may reach such proportions that civil authorities cannot maintain law and order by usual methods. Such disturbances may be caused by agitators,
racial strife, controversies between employees and employers concerning wages or working conditions, unemployment, lack of housing or food, or other economic or social conditions.”
“A city held by any organized rioters will be attacked generally in the same manner as one held by enemy troops.”
http://www.fas.org/irp/doddir/army/fm19-15.pdf