This module is a resource for lecturers
The principles of necessity, proportionality and precaution, introduced in Key Terms, are expanded upon below.
The principle of necessity
The principle of necessity has three interrelated elements: the duty to use non-violent means wherever possible; the duty to use force only for a legitimate law enforcement purpose; and the duty to use only the minimum necessary force that is reasonable in the prevailing circ*mstances.
Wherever possible, law enforcement officials should use non-violent means to achieve a legitimate law enforcement objective before resorting to physical force. This default position is explicitly affirmed in Principle 4 of the 1990 Basic Principles: "Law enforcement officials, in carrying out their duty, shall, as far as possible, apply non-violent means before resorting to the use of force and firearms. They may use force and firearms only if other means remain ineffective or without any promise of achieving the intended result." Such non-violent means include the symbols of police authority such as their presence, uniform, or vehicle; body language (including intensified eye contact with the individual); and verbal persuasion, such as by pointing out the futility of resistance. A need for law enforcement officials to use force may be reduced by their appropriate equipping with "self-defensive equipment such as shields, helmets, bulletproof vests and bulletproof means of transportation", as set out in Principle 3 of the 1990 Basic Principles. Moreover, law enforcement officials are also entitled to enjoy protection from the state of their fundamental human rights to life and to bodily integrity.
In addition, each use of force must be for a legitimate law enforcement purpose. As Article 3 of the 1979 Code of Conduct provides, law enforcement officials may use force only "to the extent required for the performance of their duty". The official commentary on this provision clarifies that law enforcement officials may use such force, and no more, "as is reasonably necessary under the circ*mstances" to prevent crime or to effect or assist in the lawful arrest of offenders or suspected offenders. The 2001 European Code of Police Ethics similarly provides that the police may use force "only when strictly necessary and only to the extent required to obtain a legitimate objective" (Council of Europe, 2001, para. 37).
Accordingly, force must never be used vindictively or as a form of extrajudicial punishment; meted out in a discriminatory manner; or applied against an individual offering no resistance. In addition, no additional force is lawful when the need has passed, such as when a suspect is safely and lawfully detained. Discriminatory practices, such as those carried out by law enforcement officials against minorities, are clearly a violation of international law.
Central to the principle of necessity, however, is that when force is necessary, it must be no more than the minimum reasonably necessary in the circ*mstances. This means that even violent or potentially violent suspects should be arrested, or killed, except in very extreme cases where using force and lethal force is the only possibility to stop an imminent risk to life. In 1982, the Human Rights Committee stated in their views in the case of Guerrero v. Colombia that the state acted unlawfully by shooting suspected terrorists instead of arresting them, as they could have done in the circ*mstances. In 2015, in Bouyid v. Belgium (No. 23380/09), the Grand Chamber of the European Court of Human Rights reiterated that "in respect of a person who is ... confronted with law-enforcement officers, any recourse to physical force which has not been made strictly necessary by his own conduct diminishes human dignity and is, in principle, an infringement" of the right to freedom from torture and inhuman or degrading treatment (para. 88, 100).
At the same time, law enforcement officials may make an honest mistake and not be held criminally liable, unless that mistake was manifestly unreasonable in the circ*mstances. In its 1995 judgment in the McCann and others v. United Kingdom (No. 18984/91) case, the Grand Chamber of the European Court of Human Rights stated that use of force by agents of the State may be justified "where it is based on an honest belief which is perceived, for good reasons, to be valid at the time but which subsequently turns out to be mistaken. To hold otherwise would be to impose an unrealistic burden on the State and its law-enforcement personnel in the execution of their duty, perhaps to the detriment of their lives and those of others" (para. 200).
The principle of proportionality
The principle of proportionality as it applies to use of force in law enforcement is often misunderstood. Proportionality does not mean that force must be used by a law enforcement official in strict accord with any use of force continuum (where the level of force is raised in stages), or as a like response to violence from a criminal suspect. Instead, it sets a ceiling on what amounts to lawful use of force, in accord with the threat posed by an individual or group of individuals and the offence that has been or is about to be committed.
According to the commentary on Article 3 of the 1979 Code of Conduct, "National law ordinarily restricts the use of force by law enforcement officials in accordance with a principle of proportionality. It is to be understood that such national principles of proportionality are to be respected in the interpretation of this provision. In no case should this provision be interpreted to authorize the use of force which is disproportionate to the legitimate objective to be achieved." Similarly, according to Principle 5 of the 1990 Basic Principles, "Whenever the lawful use of force and firearms is unavoidable, law enforcement officers shall ... act in proportion to the seriousness of the offence and legitimate objective to be achieved."
Proportionality only comes into play if the principle of necessity is respected. Thus, the use of force must already be necessary in the circ*mstances and the force actually used must be no more than the minimum necessary to achieve a legitimate law enforcement objective. The principle of proportionality may act to render such "necessary" force unlawful. So, for example, to stop an escaping thief might require a law enforcement official to use his or her firearm. In such a circ*mstance, however, the principle of proportionality will prevent such use, even where it unquestionably amounts to the minimum necessary force in any particular situation. As the Grand Chamber of the European Court of Human Rights held in 2005 in the Nachova v. Bulgaria case (No. 43577/98), an escaping suspect (who does not pose a grave threat to life) may not be shot "even if a failure to use lethal force may result in the opportunity to arrest the fugitive being lost" (para. 95).
With respect to an electric-shock weapon, such as a Taser TM, national case law has noted the relevance of proportionality. In Armstrong v. Village of Pinehurst, the United States Court of Appeals for the Fourth Circuit, held that: "Immediately tasing a non-criminal, mentally ill individual, who seconds before had been conversational, was not a proportional response." Electric shock weapons, the Court held, "are proportional force only when deployed in response to a situation in which a reasonable officer would perceive some immediate danger that could be mitigated by using the taser" (2016, p. 19, 21.)
The principle of precaution
The principle of precaution underpins the principles of necessity and proportionality. Under the principle of precaution, the state is duty bound to plan law enforcement operations in a manner that minimizes the risk of law enforcement agencies and officials having recourse to potentially lethal force. The rationale is to limit the risk of death or serious injury to any member of the public or law enforcement official. According to Principle 5(b) of the 1990 Basic Principles, whenever lawful use of force and firearms is unavoidable, law enforcement officials must "minimize damage and injury" and "respect and preserve human life". But measures need to be taken "upstream" in the operational planning phase to "avoid situations where the decision on whether to pull the trigger arises, or to ensure that all the possible steps have been taken to ensure that if that happens, the damage is contained as much as is possible" (UN Special Rapporteur on Summary Executions, 2014, para. 69).
The precautionary principle was first enunciated by the European Court of Human Rights in its 1995 Grand Chamber judgment in the McCann v. United Kingdom (No. 18984/91) case: "the Court must carefully scrutinise ... not only whether the force used by the soldiers was strictly proportionate to the aim of protecting persons against unlawful violence but also whether the anti-terrorist operation was planned and controlled by the authorities so as to minimise, to the greatest extent possible, recourse to lethal force" (para. 194). The Inter-American Court of Human Rights has held that proportionality "is also related to the planning of preventive measures, since it involves an assessment of the reasonableness of the use of force. Thus, it is useful to analyze the facts rigorously to determine ... whether the violations could have been avoided with the implementation of less harmful measures" (Inter-American Court of Human Rights, 2012, para. 87).
In addition, with a view to preserving life, according to Basic Principle 5(a) of the 1990 Basic Principles, law enforcement officials must also ensure that "assistance and medical aid are rendered to any injured or affected persons at the earliest possible moment". This must equally be part of the planning process for law enforcement operations. In the Finogenov v. Russia case (No. 18299/03) in 2011, the European Court of Human Rights examined whether the hostage rescue operation was planned and implemented in compliance with the authorities' positive obligations under the right to life in Article 2 of the 1950 European Convention on Human Rights, "namely whether the authorities took all necessary precautions to minimise the effects of the gas on the hostages, to evacuate them quickly and to provide them with necessary medical assistance" (para. 237). The duty to assist applies even if the injured person is a suspected offender.
