Use of force
The use of force, in the context of law enforcement, may be defined as the "amount of effort required by police to compel compliance by an unwilling subject".
Use of force doctrines can be employed by law enforcement officers and military personnel on guard duty. The aim of such doctrines is to balance the needs of security with ethical concerns for the rights and well-being of intruders or suspects. Injuries to civilians tend to focus attention on self-defense as a justification and, in the event of death, the notion of justifiable homicide.
Police use physical force to the extent necessary to secure observance of the law or to restore order only when the exercise of persuasion, advice and warning is found to be insufficient.— Sir Robert Peel, "Principles of Law Enforcement"
U.S. military personnel on guard duty are given a "use of force briefing" by the sergeant of the guard before being assigned to their post.
For the English law on the use of force in crime prevention, see Self-defence in English law. The Australian position on the use of troops for civil policing is set out by Michael Hood in Calling Out the Troops: Disturbing Trends and Unanswered Questions; compare "Use of Deadly Force by the South African Police Services Re-visited" by Malebo Keebine-Sibanda and Omphemetse Sibanda.