By the very nature of their job, law enforcement officers are tasked with using physical force to restrain individuals and protect themselves and others from harm. Police officers must stop and seize violent suspects, serve search warrants in hostile environments, and maintain the peace and safety of the communities in which they serve. As then-Justice Rehnquist observed, "[p]olicemen on the beat are exposed, in the service of society, to all the risks which the constant effort to prevent crime and apprehend criminals entails: Because these people are literally the foot soldiers of society's defense of ordered liberty, the State has an especial interest in their protection." However, a number of recent high-profile police shootings and other law enforcement-related deaths have reignited the debate about how much force police should wield in a democratic society that values both law and order and the personal liberty of each of its citizens under law. The shooting of Michael Brown by a Ferguson, Missouri police officer in the summer 2014 served as a flashpoint for this debate, but it is just one in a spate of recent law enforcement-related deaths. These deaths, and others, have prompted a call for legal accountability against the officers involved in these killings, but also, more broadly, for systemic police reform on both the federal and state level. President Obama responded by establishing the Task Force on 21 st Century Policing in December 2014 to develop best policing practices and recommendations. The task force's final report issued in May 2015 offered a set of policy recommendations focused on training, investigations, prosecutions, data collection, and information sharing. Similarly, the House Judiciary Committee held a hearing on policing strategies on May 19, 2015, and various measures have been introduced in the 114 th Congress to address both use of force tactics and data collection by state and local police departments. The public, too, has been thoroughly engaged on this issue. "Black Lives Matter," a movement that sprung up in response to the Treyvon Martin shooting and other police-related deaths, has recently released an initiative called "Campaign Zero," which contains a set of policy proposals to limit police use of excessive force, including a call for a national standard governing the use of deadly force and better reporting requirements on instances of excessive force by law enforcement officers. These reforms prompt the perennial debate concerning the role of Congress in addressing police reform, especially on the local level, where many of these deaths have occurred. Certain segments of the law enforcement community and its supporters have argued that regulating local police is best left to the province of state and local governments, and that a one-size-fits-all approach would hamper local experimentation. Proponents of reform have countered that federal intervention is warranted as state and local governments and police departments have not adequately held their officers legally accountable for the improper use of force. Insofar as constitutional violations are concerned, there is historical precedent for congressional intervention. Shortly after the Civil War, Congress enacted two federal statutes—one criminal and one civil—to provide legal remedies for newly freed African Americans who were being deprived of their civil rights. On the civil side is 42 U.S.C. Section 1983, which provides individuals with a civil cause of action to recover damages for the deprivation of such rights. On the criminal side is 18 U.S.C. Section 242, which makes it a federal crime to willfully deprive someone of his constitutional rights. Of more recent vintage (1994) is 42 U.S.C. Section 14141, which permits the Department of Justice (DOJ) to sue local police departments that engage in a "pattern or practice" of constitutional violations, including the use of excessive force. To provide legal context for this debate, this report will address three overarching questions: (1) what are the constitutional rules governing an officer's use of force; (2) what role has Congress played in providing a remedy for a violation of these rules; and (3) what are the potential reforms to these rules and remedies? The first question that must be addressed is what rules govern police use of force. Because the majority of recent law enforcement-related deaths have arisen in the context of street encounters with police (rather than pre- or post-trial detention), this report will focus almost exclusively on the Fourth Amendment right to be free from unreasonable seizures, which governs such encounters. The Fourth Amendment guarantees "the right of the people to be secure in their persons, houses, papers, and effects, from unreasonable searches and seizures." While this provision is best known for providing restraints on government searches and surveillance and the procedures under which they may be conducted, in a series of cases beginning in the 1980s the Supreme Court interpreted the Fourth Amendment as the primary federal legal restraint on excessive force. Prior to these cases, the lower circuit and district courts largely applied the substantive component of the Due Process Clause to all claims of excessive force, deadly or otherwise. However, in Tennessee v. Garner and Graham v. Connor , the Court grounded all excessive force claims in the Fourth Amendment's right to be free from unreasonable seizures. In the 1985 case Tennessee v. Garner , the Court assessed whether Tennessee's deadly force statute—which, like those of other states at the time, permitted police to use deadly force to shoot a fleeing felon—passed constitutional muster. In that case, police were responding to a reported burglary when an officer at the scene saw a young African American male fleeing the back of the house, apparently unarmed. In an effort to prevent his escape, the officer yelled for the suspect to halt and, when he failed to do so, shot him in the back of the head as he was climbing over a fence. The shot was fatal. The victim's family brought a civil suit under Section 1983 for the alleged violation of the deceased's constitutional rights. The federal district and circuit courts both held that the officer had acted in good faith on Tennessee's use of force statute, which provided that "[i]f, after notice of the intention to arrest the defendant, he either flee or forcibly resist, the officer may use all the necessary means to effect the arrest." In a 6-3 decision authored by Justice White, the Supreme Court reversed and held that the use of deadly force against a fleeing felon is unconstitutional. With little discussion of prior excessive force cases, Justice White noted that the use of deadly force is a "seizure" under the Fourth Amendment that must be "reasonable," the touchstone of all Fourth Amendment protections. To determine a seizure's reasonableness, a reviewing court must "balance the nature and quality of the intrusion on the individual's Fourth Amendment interests against the importance of the governmental interests alleged to justify the intrusion." On the individual's side of the ledger, the Court noted that the "intrusiveness of a seizure by means of deadly force is unmatched." On the government's side, the Court highlighted the government's various law enforcement interests, including arresting suspects peacefully without putting the public at risk. Balancing these interests, the Court ultimately held that the "use of deadly force to prevent the escape of all felony suspects, whatever the circumstances, is constitutionally unreasonable." Rather than furthering the goals of the criminal justice process, Justice White noted that killing a suspect ensures that this system will never be put in motion as the government cannot bring a deceased person to justice. While rejecting the application of deadly force against an individual for merely committing a felony, the opinion went on to describe when such force is permissible: Where the officer has probable cause to believe that the suspect poses a threat of serious physical harm, either to the officer or to others, it is not constitutionally unreasonable to prevent escape by using deadly force. Thus, if the suspect threatens the officer with a weapon or there is probable cause to believe that he has committed a crime involving the infliction or threatened infliction of serious physical harm, deadly force may be used if necessary to prevent escape, and if, where   feasible, some warning has been given. Note that Garner arose in the context of the use of deadly force. Four years later, the Court in Graham v. Connor addressed whether this same rule should extend to the use of non -deadly force. In Graham v. Connor , police officers pulled over an individual suspected of shoplifting. In response to his erratic behavior, one of the officers forcefully slammed him on the hood of a police cruiser and threw him headfirst into the car. The suspect sustained significant injuries and sued the police for excessive force under Section 1983. Resolving a dispute in the lower federal courts about whether the Fourth Amendment applied outside the context of deadly force, the Supreme Court held that " all  claims that law enforcement officers have used excessive force—deadly or not—in the course of an arrest, investigatory stop, or other 'seizure' of a free citizen should be analyzed under the Fourth Amendment and its 'reasonableness' standard." Writing for the Court, Chief Justice Rehnquist observed that "[t]he test of reasonableness under the Fourth Amendment is not capable of precise definition or mechanical application." Instead, "its proper application requires careful attention to the facts and circumstances of each particular case, including the severity of the crime at issue, whether the suspect poses an immediate threat to the safety of the officers or others, and whether he is actively resisting arrest or attempting to evade arrest by flight." These three factors have taken on considerable importance in use of force jurisprudence in the lower courts. Additionally, Chief Justice Rehnquist described the interpretive lens through which excessive force cases must be viewed. First, the "'reasonableness' of a particular use of force must be judged from the perspective of a reasonable officer on the scene, rather than with the 20/20 vision of hindsight." Second, the "calculus of reasonableness must embody allowance for the fact that police officers are often forced to make split-second judgments—in circumstances that are tense, uncertain, and rapidly evolving—about the amount of force that is necessary in a particular situation."