Why not? In brief, society restricts the ability of officers to use force because the use of force itself infringes on the subject’s individual interest in liberty, bodily autonomy, and personal safety; on the more generalized governmental interests in preserving legitimacy and public trust; and on the specific governmental interest in protecting the physical safety of its constituents. In other words, the use of force by police infringes on highly valued personal and state interests. Because the use of force is viewed—properly, in our view—as an infringement on individual and governmental interests, and because we do not allow the government to lightly infringe on such interests, the use of force is only permissible when it is specifically justified (as opposed to being generally permitted unless prohibited).
Having established that officers may only use force when it is justified, the question remains: what justifies police uses of force?
Perhaps the most conceptually sound answer to that question comes from law professor Rachel Harmon, who concluded that force can be legitimately used only when there is an “imminent threat” to certain pre-defined governmental interests.29
It is important to note at the outset that these three governmental interests that justify the police in using force are prospective. The use of force is required to achieve one of the identified goals at some point in the future. A use of force cannot be predicated on purely retrospective governmental interest. For example, it would be highly inappropriate for a police officer to use force to retributively punish a criminal suspect for a previously committed crime; the state’s interest in punishing offenders is predicated on a formal adjudication of guilt, either through conviction by a jury or a guilty plea. Only once there is adjudication can the state impose punishment.30 An officer may, however, use force to effect an arrest of a suspect who would otherwise escape; doing so is prospective, not retrospective, because the officer is acting pursuant to the state’s interest in doing something in the future—here, subjecting the subject to a formal prosecution.
However, merely having a prospective interest is not sufficient to justify the use of force. The government has an interest in deterring future crime, for example, but it would be manifestly inappropriate for an officer to beat the individuals they come across as a way of encouraging them to avoid breaking the law in the future.31 Some, but not all, prospective governmental interests can justify the use of force; Harmon has identified, and we endorse, only three.
First, the state has an interest in law enforcement: “facilitating [the government’s] institutions of criminal law.”32 This interest can justify an officer’s actions only after a crime has been committed—or, more accurately, is believed to have been committed—although force is used in such situations to ensure that they can satisfy the state’s interest in law enforcement in the future. Officers cannot effectively investigate suspected crimes without the ability to detain persons whom they reasonably suspect to have committed those crimes, for example, and, in the event of a prosecution, the criminal justice system requires the presence of the individual who is charged with a crime, of witnesses, and of evidence. Through the application of certain legal processes, such as the issuance of an arrest warrant, a subpoena, or a search warrant, the state “expressly commands” individuals to comply by submitting to an investigation, or appearing, or testifying. As Harmon explains, these state commands can be implicit as well; when a state gives officers the authority to make an arrest or conduct a search without a warrant, implied in that authority is a command for the individual to comply. These commands implicate the state’s interest in enforcing the law against those individuals who are believed to have violated it. “Police uses of force,” Harmon writes, “are then justified to ensure that these commands are satisfied, that our criminal justice institutions function after a crime [is believed to have] occurred.”
Second, the state has an interest in order maintenance: force can be justified “when it is necessary to eliminate a significant threat to public safety.” As described above, this interest is prospective; it can justify an officer’s actions only prior to the commission of a crime (or the infliction of harm on an individual) when the use of force is seen as a way of averting that crime (or harm). This interest can overlap to some degree with the government’s interest in law enforcement. Harmon provides the example of officers breaking up a fight between teenagers. At the moment they forcibly separate the combatants, the officers may be acting both in their order-maintenance capacity, by using force to prevent harm to the combatants and bystanders, and in their law-enforcement capacity, by arresting the individuals so they may be charged criminally. It is equally possible, however, for officers to use force to maintain public order even without a criminal predicate. “Thus, a police officer may use force to stop a distraught person from committing suicide or to break up a rowdy crowd that could injure by riot or stampede, even though doing so entails applying force against someone who is not yet violating a criminal statute.”33 In other words, a use of force to prevent an individual’s suicide may be entirely appropriate even though there is no crime on the statute books that would criminally punish the person’s actions. (Although all United States jurisdictions have repealed statutes that criminally punish suicide and attempted suicide, some states continue to treat it as a common law crime.34) It can, in any individual case, be difficult to identify when the state’s interest in order maintenance is fully manifested and when there is a threat that is sufficiently imminent so as to justify an officer’s use of force. “But even though the edges of legitimate police efforts to protect the public are contested and blurry, the [immediate] prevention of crime and the maintenance of public safety remain central to contemporary policing.”35
Third, the state has an interest in officer safety: force may be used to protect officers from physical threats to their safety. Notice, again, that this interest is prospective; it justifies force as a way to avert a physical hazard that would otherwise cause harm to the officer. The individual officer has a personal interest in their own safety, of course, but an officer has no greater interest in their own safety than anyone else does—if the individual interest in safety were the only interest at stake, we could simply apply the law of self-defense in situations in which officers used force to protect themselves.36 The state, however, has a distinct interest in protecting officers. Without officers, the state’s interests in law enforcement and order maintenance would be easily frustrated, leading Harmon to describe the interest in officer safety as “derivative” of the other two interests. “Because human police officers are the instruments by which the state pursues its interests in law and order, threats to those police officers often result in justified defensive force in excess of what would otherwise be required to serve the state’s interests.” It is for that reason that jurisdictions that have retained the common-law duty to retreat, which requires individuals who can safely retreat instead of using self-defense to do so, do not impose that requirement on police officers.37
Although the three factors are distinct, two or even all three may be present in any given case. This is particularly true when an officer has the legal authority to take a particular action or issue a particular order, when a subject attempts to impede that action or refuses to obey that order, and when the impediments or refusals constitute criminal violations. Consider a situation in which officers are authorized to enter a private