S everal high-profile incidents where police officers have been involved in the deaths of citizens reinvigorated a discussion about how the police use force against minorities and the tension that exists between police officers and minority communities. The national debate about how police use force and police-community relations might generate interest among policymakers about what role Congress could play in facilitating efforts to build trust between the police and the people they serve, as well as police accountability for any excessive use of force. The report starts with an overview of data on public opinion of the police. It then provides a brief discussion of federalism and why Congress does not have the authority to directly change state and local law enforcement practices. Next, the report reviews federal efforts to collect data on law enforcement agencies' use of force and federal authority to investigate instances of police misconduct. This is followed by a review of what role DOJ might be able to play in facilitating improvements in police-community relations or making changes in state and local law enforcement agencies' policies. The report concludes with policy options for Congress to consider should policymakers decide to exert some influence on state and local law enforcement agencies' policy. Gallup, whose polling tracks confidence in a variety of institutions, found that the public's level of confidence in police is back to its historical norm after a decrease in 2014 and 2015 (see Figure 1 ). In 2017, 57% of Americans said they had a "great deal" or "quite a lot" of confidence in the police, which matched the 25-year average for Gallup polling. Fifty-seven percent of Americans reported that they had a "great deal" or "quite a lot" of confidence in the police in 2013, but confidence decreased to 53% in 2014, and decreased again to 52% in 2015, which was a historical low in Gallup polling. Even at its nadir in 2015, people still had more confidence in the police than many other institutions. Only the military (72%) and small business (70%) had higher percentages of respondents voicing confidence in the respective institutions than the police. Confidence in the police varies by race/ethnicity, political ideology, and age (see Table 1 ). Whites were more likely to say that they have a "great deal" or "quite a lot" of confidence in the police than Hispanics and blacks. In addition, whites' confidence in the police has increased while that of Hispanics and blacks has decreased. Variability in confidence is also evidenced among people who identify as conservative, moderate, and liberal. Conservatives are more likely than liberals and moderates to have confidence in the police, and their confidence has increased in recent years while that of moderates and liberals has decreased. In addition, a smaller proportion of people age 18-34 said they were confident in the police compared to people age 35-54 and people 55 and older, with the 55 and older group having the greatest proportion of people saying that they had a "great deal" or "quite a lot" of confidence in the police. Policymakers may have an interest in trying to help increase trust between the police and certain communities, particularly in urban areas. Policymakers may seek to increase law enforcement agencies' accountability for any excessive use of force and address state and local law enforcement policies they believe contribute to the lack of public trust in police. However, the United States' federalized system of government places limits on the influence Congress can have over state and local law enforcement policies. Federalism describes the intergovernmental relationships between and among federal, state, and local governments, with the federal government having primary authority in some areas and state and local governments having primary authority in other areas. Scholars have variously described these relationships as being primarily "dual," "cooperative," "creative," "coercive," or, more recently, "fragmented" federalism. Early characterizations of the American system described a dual federalism in which the federal and state governments were equal partners with relatively separate and distinct areas of authority. Scholars argue that American federalism is presently "more chaotic, complex, and contentious than ever before." This has led to a fragmented federalism in which states and the federal government simultaneously pursue their own policy priorities, and policy implementation often occurs in a piecemeal, disjointed fashion. Under the authority of the Spending Clause of the U.S. Constitution, Congress may choose to impose conditions on federal grant awards to state and local governments as a way to influence state and local policy. As one scholar noted, congressional conditioning of federal grants related to state and local policing under the authority of the Spending Clause has been questioned: Law enforcement historically has been considered one of these attributes of state sovereignty upon which the federal government cannot easily infringe. Thus, Congress is greatly restricted in the degree to which it can regulate a state's administration of its local law enforcement agencies. Because of this limited power over the states, particularly in areas such as law enforcement, Congress cannot "commandee[r] the legislative processes of the States by directly compelling them to enact and enforce a federal regulatory program. Furthermore, even if Congress has the authority to regulate or prohibit certain acts if it chooses to do so, it cannot force the states "to require or prohibit those acts." In contrast, another scholar has suggested that federal grants to law enforcement agencies are a way to encourage police accountability and argued that "federal funds issued to states ... should be conditioned upon the enactment and implementation of police accountability measures aimed at institutional reform." That same scholar also suggested that the use of federal grants to state and local law enforcement agencies can encourage a cooperative federalism relationship that entails federal-state collaboration and allows states some flexibility in implementing federal standards while preserving state and local abilities to enhance police accountability. Another federalism scholar noted that cooperative federalism was "a pragmatic middle ground between reform and reaction that would not destroy the states but would still lower their salience from constitutionally coordinate polities to more congenial laboratories of democracy and administrators of national policy." While there is limited research on the evolving nature of federalism within law enforcement policy, the congressional use of federal grants to state and local law enforcement agencies, and the cooperative federalism that generally exists through their use, suggest that the federalism relationship in this area may be less fragmented than in other policy areas. It is unclear how changes in federal interaction with state and local law enforcement agencies might affect the nature of federalism outside this specific policy area. Even though there are limits on how much influence Congress and the federal government can have on state and local law enforcement policy, the federal government does currently have some tools that might be used to promote better police-community relations and accountability. These include (1) federal efforts to collect and disseminate data on the use of force by law enforcement officers; (2) statutes that allow the federal government to investigate instances of police misconduct; and (3) the influence DOJ has on state and local law enforcement policies through its role as a public interest law enforcer, policy leader, convener, and funder of law enforcement agencies. The high-profile deaths of several members of the public at the hands of police officers has generated questions about why the federal government does not collect and publish data on the use of force by law enforcement officers. Former Philadelphia Police Chief Ramsey, one of the co-chairs of the Task Force on 21 st Century Policing, stated "personally, I think [how data on civilian and law enforcement officers' deaths are collected] ought to be pretty much the same. If you don't have the data, people think you are hiding something.... This is something that comes under the header of establishing trust." It may be that the lack of reliable data on how often police use force and who is the subject of the use of force fuels the public's mistrust of the police. Without more comprehensive data to provide context in this area, the public is left to rely on media accounts of excessive force cases for information. The lack of comprehensive federal data on police-involved deaths led the Washington Post to start its own database of people who have been shot and killed by the police. The federal government currently has several different programs that collect some data on police-involved shootings and the use of force. However, none of these programs collects data on every use of force incident in the United States. Currently, the Federal Bureau of Investigation (FBI), through the Uniform Crime Report (UCR), collects data on justifiable homicides by law enforcement officers. It does not collect data on shootings that do not result in a death, nor does it capture data in instances where an officer shoots at a suspect but does not hit him or her. Also, law enforcement agencies participate in the UCR program voluntarily, which means that justifiable homicides by law enforcement agencies may be undercounted. One DOJ statistician has stated that "the FBI's justifiable homicides [data] ... [has] significant limitations in terms of coverage and reliability that [are] primarily due to agency participation and measurement issues." The FBI notes that "the opportunity to analyze information related to use-of-force incidents and to have an informed dialogue is hindered by the lack of nationwide statistics." The FBI reports that it is working with major law enforcement organizations to collect national use of force data. The stated goal of the program is "is not to offer insight into single [use of force] incidents but to provide an aggregate view of the incidents reported and the circumstances, subjects, and officers involved." Also, the data will not assess whether the officers involved in use of force incidents acted lawfully or within the bounds of department policy. The FBI plans to collect data on use of force incidents that results in the death or serious bodily injury of a person or when a law enforcement officer discharges a firearm at or in the direction of a person.