Use of force
A use of force doctrine is employed by police forces, as well as soldiers on guard duty, to regulate the actions of police and guards. The aim of such a doctrine is to balance security needs with ethical concerns for the rights and well-being of intruders or suspects. In the event that members of the public are injured, this may give rise to issues of self-defense as a justification. In the event of death, this may be a justifiable homicide.
U.S. soldiers 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 by police officers and soldiers in the prevention of crime, 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  and, for comparative purposes, see *Keebine-Sibanda, Malebo J. & Sibanda, Omphemetse S. "Use of Deadly Force by the South African Police Services Re-visited". .
Use of force continuum
The use of force may be standardized by a use of force continuum, which presents guidelines as to the degree of force appropriate in a given situation. One source identifies five very generalized steps, increasing from least use of force to greatest. It is only one side of the model, as it does not give the levels of subject resistance that merit the corresponding increases in force. Each successive level of force is meant to describe an escalating series of actions an officer may take to resolve a situation, and the level of force used rises only when a lower level of force would be ineffective in dealing with the situation.
- Presence (using the effect of the presence of an authority figure on a subject)
- Verbalization (commanding a subject)
- Empty hand control (using empty hands to search, relieve weapons, immobilize, or otherwise control a subject)
- Intermediate weapons (using non-lethal chemical, electronic or impact weapons on a subject)
- Deadly Force (using any force likely to cause permanent injury or death to a subject)
Use of force continuums can be further broken down.
England and Wales
"A person may use such force as is reasonable in the circumstances in the prevention of crime, or in effecting or assisting in the lawful arrest of offenders or suspected offenders or of persons unlawfully at large".
Use of force may be considered lawful if it was, on the basis of the facts as the accused honestly believed them, necessary and reasonable.
- Basic Principles on the Use of Force and Firearms by Law Enforcement Officials, Eighth United Nations Congress on the Prevention of Crime and the Treatment of Offenders, Havana, 27 August to 7 September 1990, U.N. Doc. A/CONF.144/28/Rev.1 at 112 (1990).