Pragmatically, there are several reasons to take police uses of force seriously. First, such incidents result in the injury or death of thousands of community members every year. Although the proportion of police–civilian interactions that involve violence are quite modest, the small percentage masks large absolute numbers. Even if force is used in only 1 percent of police–civilian encounters, the fact that there are, on average, more than sixty million such encounters every year would mean that there are at least 600,000 uses of force every year. That’s more than one every minute in every hour of every day of the year. Most of the time, officers are not using force to defend themselves: over the last ten years, there have been, on average, about 56,000 incidents every year in which an officer was assaulted (just over a quarter of those assaults resulted in some type of injury to the officer). That leaves at least 544,000 occasions each year in which officers used force for reasons other than self-defense. That breaks down to almost 1,500 every day, which is still more than one per minute. Those numbers are at the low end of the spectrum based on data from the Bureau of Justice Statistics; if more than 1 percent of police–civilian encounters involve the use of force or if there are more than sixty million encounters in a given year, the absolute numbers may be significantly larger. The potential number of use-of-force incidents, then, make this an issue of public importance.
The use of force also plays an important role in shaping public attitudes toward government generally and policing more specifically. Police violence is among the most controversial uses of governmental authority. Community trust and confidence in the police is undermined by the perception that officers are using force unnecessarily, too frequently, or in problematically disparate ways. Over time, negative perceptions of the police can reduce civilian cooperation, making law enforcement and order maintenance significantly more difficult. Public distrust can also create dangerous situations for officers and community members. The use of force not only undermines public trust over time, it can also serve as a flashpoint, a spark that ignites long-simmering community hostility. Use-of-force incidents can have lasting reverberations, from the televised abuses of the Civil Rights Era to the beating of Rodney King in 1991, and from the shooting of Amadou Diallo in 1999 to the shooting of Walter Scott in 2015. Throughout the country, police uses of force have instigated violence or civil unrest.4 Of the ten most violent and destructive riots in United States history, fully half were prompted by what were perceived as incidents of excessive force or police abuse.5
The central role that use-of-force incidents play in shaping public perceptions of policing is all the more critical in light of the limited information that most community members have about policing and the use of force. Traditional and social media shape public perceptions, but that coverage can lead to misperceptions about the frequency and substance of use-of-force incidents. Citizens often learn about police behavior from entertainment media—television, movies, video games, and so on—but such portrayals are rarely accurate. Even when news media provides more accurate reports of how force is used, the public can be left with an incomplete or inaccurate understanding about the use of force. During oral argument in a Supreme Court case involving officers who shot at a fleeing vehicle, for example, the late Justice Antonin Scalia asserted that officers shoot at moving vehicles “all the time”; this highly questionable statement was predicated not on data from academic studies or specific police agencies, but rather on “movies about bank robberies.”6
In the aggregate, reporting on police uses of force naturally focuses on what are viewed as the most newsworthy events: particularly officer-involved shootings, brutal violence, or egregious misconduct. Because of a cognitive bias known as the “availability heuristic”—which causes us to make judgments about the frequency of an event based in large part on our awareness of other similar, recent, and significant events—such reporting can contribute to the false impression that such events are far more frequent than they actually are. A recent, high-profile incident of police violence in the news, then, can lead people to conclude that similar incidents of police violence are quite common even when that may not be the case.
Public misunderstandings about the use of force can also affect the way individual incidents are perceived. News reports, especially preliminary reports, are of limited value: inevitably, there is a significant amount of information the reporters—and, by extension, the public—simply do not have at the time. Many viewers, however, will come to a firm conclusion based on partial information, unconsciously relying on a host of cognitive biases to fill in the gaps. Worse, many viewers will have a high degree of confidence in their conclusions. As a result, a use-of-force incident may be judged by thousands of people who develop strong opinions based on weak and incomplete evidence.7 And even when there is good information about a particular incident, most people simply do not apply any rigorous analytical framework to evaluate the use of force. That matters because police violence is just that: violence. Even when we are quite comfortable with the abstract proposition that officers use force, the actual use of force can be aggressive, brutal, and ugly. When force is, or appears to be, excessive or unnecessary, it can create the perception that a government official charged with ensuring public safety turned on a member of the public they are sworn to protect.
These philosophical and pragmatic rationales make it incredibly important for officers to use force appropriately and for officers and agencies to be held accountable when they do not. This book poses and responds to a question that is central to police accountability: how does society evaluate the propriety of an officer’s use of force? That is, how do we tell whether any given use of force appropriately balanced the subject’s interest in freedom against the social interests in order and law enforcement? We identify four different answers to that question, four evaluative standards that can be—and are—used in different contexts. Chapter 1 provides a detailed roadmap of constitutional standards, where the propriety of police force is regulated by the Fourth Amendment’s prohibition of unreasonable seizures. Chapter 2 supplies an overview of state law, which sets out criminal and civil standards. Chapter 3 explores the administrative standards that individual police agencies create through policy, procedure, and training. Chapter 4 discusses what we term the “community expectations standard,” an important, if informal, way to evaluate police uses of force through the lens of public expectations. In each chapter, we engage in a detailed discussion of one relevant standard, identifying the contexts in which that standard applies, describing the precise behaviors that each standard regulates, and exploring how each evaluative standard is used to assess the propriety of any given use of force.
In the final two chapters, we provide key information about the choices police make in use-of-force situations; understanding these choices is essential for applying any of the evaluative standards. In chapter 5, we discuss police tactics: the decisions that officers make and the actions they take as they approach and interact with civilians, both of which can contribute to whether and how force is used. In chapter 6, we explore the various ways officers use force, describing the role various techniques, tools, and weapons can play in use-of-force situations, and highlighting the continued development of tools and technologies that may shape when and how officers use force.
These discussions about the evaluative standards, and the additional information that is necessary to apply those standards effectively, are situated within a broader conversation about governmental accountability, the role that police play in modern society, and how officers should go about fulfilling their duties. We acknowledge the value of, but do not here explicitly engage in, those more extensive themes. This book does not claim to resolve, or even to address, all of the problems in policing; indeed, our focus on the evaluative frameworks that can be applied to use-of-force incidents is quite limited. This book explores how individual use-of-force incidents are evaluated, but we do not here examine how the use of force is