Broadly speaking, the use of force by law enforcement officers becomes necessary and is permitted under specific circumstances, such as in self-defense or in defense of another individual or group.
There is no single, universally agreed-upon definition of use of force. The International Association of Chiefs of Police has described use of force as the "amount of effort required by police to compel compliance by an unwilling subject" .
Officers receive guidance from their individual agencies, but no universal set of rules governs when officers should use force and how much.
Context counts. No two situations are the same, nor are any two officers. In a potentially threatening situation, an officer will quickly tailor a response and apply force, if necessary. Situational awareness is essential, and officers are trained to judge when a crisis requires the use of force to regain control of a situation. In most cases, time becomes the key variable in determining when an officer chooses to use force.
Amount of Force Used
Law enforcement officers should use only the amount of force necessary to mitigate an incident, make an arrest, or protect themselves or others from harm. The levels, or continuum, of force police use include basic verbal and physical restraint, less-lethal force, and lethal force.
The level of force an officer uses varies based on the situation. Because of this variation, guidelines for the use of force are based on many factors, including the officer’s level of training or experience.
An officer’s goal is to regain control as soon as possible while protecting the community. Use of force is an officer’s last option — a necessary course of action to restore safety in a community when other practices are ineffective.
Injuries may occur in any use-of-force incident, and police should ensure that those injured receive medical aid and that the family of any injured person is notified.
Excessive force. The frequency of police use-of-force events that may be defined as justified or excessive is difficult to estimate . There is no national database of officer-involved shootings or incidents in which police use excessive force. Most agencies keep such records, but no mechanism exists to produce a national estimate.