Unit 34: Force by Law Enforcement


  • Dressler 259-269

  • Mo. Rev. Stat. 563.041 (CP)

  • DOJ Report (CP)

Key Terms: 

Public authority, public duty, citizen arrests, crime prevention, effectuation of an arrest


Public Authority Defense

At common law, law enforcement officers are authorized to make an arrest if they have “reasonable” or “probable” cause. This authority is now also subject to the constraints of the Fourth Amendment.

Private citizens also have common law authority to make “citizen arrests” to enforce a felony or breach of the peace if (1) the crime actually occurred and (2) the citizen reasonably believes that the suspect committed the offense. The reasonableness standard applies only to the second element and not to the first. Therefore, a citizen cannot avail himself of this authority if he reasonably but mistakenly believes that a crime occurred. The Fourth Amendment does not apply to private citizens making arrests.

The Model Penal Code recognizes a public duty defense where law enforcement is required or permitted by: (1) a law defining the duties of a government officer; (2) a law pertaining to the execution of legal process; (3) an order of a court; or (4) any other law imposing a public duty on the actor. See MPC 3.03(1).

The public duty defense is also available in two circumstances where a person believes she is authorized to act but actually is not: (1) where a law enforcement officer incorrectly believes that her conduct is authorized “by the judgment or direction of a competent court or tribunal or in the lawful execution of legal process” (e.g., an arrest based on a defective warrant); and (2) where a private citizen mistakenly believes he is authorized to assist a law enforcement officer in her duties, but where the officer was actually acting beyond her authority. See MPC 3.03(3)(a)–(b).

Crime Prevention

At common law and under the Model Penal Code, a police officer or private citizen may use force either to prevent the commission or consummation of a crime or to make an arrest.

At common law, a police officer or private person is justified in using nondeadly force if she reasonably believes that: (1) a person is committing or has committed a felony or a misdemeanor breaching the peace; and (2) the forced used is necessary to prevent commission of the offense.

Deadly force at common law could be used to prevent the commission of any felony, even nonviolent ones. Most jurisdictions today recognize a much narrower rule, limiting the use of deadly force to the prevention of “forcible” or “atrocious” felonies involving the use or threat of physical force or violence against another person.

Under the Model Penal Code, a police officer or private person is justified in using force to prevent commission of a crime if she believes that: (1) the person is about to commit suicide, inflict serious bodily injury upon herself, or commit a crime involving or threatening bodily injury, damage to or loss of property, or a breach of the peace; and (2) the force is immediately necessary to prevent commission of the act. See MPC 3.07(5)(a).

The Model Penal Code authorizes a police officer or private person to use deadly force to prevent the commission of a crime only if she believes that: (1) there is a substantial risk that the suspect will cause death or serious bodily injury to another person unless she prevents the suspect from committing the offense; and (2) use of deadly force presents no substantial risk of injury to bystanders. See MPC 3.07(5)(a)(ii)(A). In contrast, only public officers and those aiding them may use this defense in the arrest process. These standards are somewhat stricter than the rules regarding the use of deadly force in defense of property, which disregard the risk to bystanders and, in some circumstances, allow the use of deadly force even when the actor is no longer threatened.

Effectuation of an Arrest

At common law, a police officer’s authority to use force in effectuating an arrest is the same as her authority to use force in preventing a crime. However, a police officer’s right to use deadly force to effectuate an arrest is much broader than her right to use deadly force for crime prevention. Although deadly force must still be necessary to make an arrest or prevent the suspect from escaping, it can be used to effectuate arrests involving forcible or nonforcible felonies (within constitutional limits). The right of private persons to use deadly force when reasonably necessary to arrest or apprehend a felon is narrower than that of police officers. The rules vary be states, but the majority include limitations such as that the offense must be a forcible felony; the arresting party must give the suspect notice of her attempt to make the arrest; and the suspect must have actually committed the crime.

Under the Model Penal Code, a police officer or private person is justified in using force in making an arrest or preventing an escape if the actor: (1) believes that force is immediately necessary to effectuate a lawful arrest or prevent escape; and (2a) makes known to such person the purpose of the arrest or (2b) believes that the person understands the purpose of the arrest or that notice cannot reasonably be provided. See MPC 3.07(1), 3.07(2)(a), 3.07(3).

The justified use of deadly force by a police officer making an arrest is much narrower, and the use of deadly force by a private person acting alone to make an arrest is never justified. Deadly force may be used by a police officer, or a private person assisting someone whom she believes is a law enforcement officer, to make an arrest or to prevent the suspect’s escape if: (1) the requirements for the use of force above are met (2) the arrest is for a felony; (3) the actor believes that the use of deadly force creates no substantial risk of harm to innocent bystanders; and either (4a) the actor believes that the crime included the use or threatened use of deadly force; or (4b) the actor believes that a substantial risk exists that the suspect will kill or seriously harm another if her arrest is delayed or if she escapes. See MPC 3.07(2)(b). Notice the important differences between the Code and common law pertaining to the authority of private citizens, the risk of substantial harm to bystanders, and the use of deadly force in making arrests for nonforcible felonies.

Constitutional Limits to the Use of Force in Arrests

The Fourth Amendment prohibits “unreasonable searches and seizures” of persons and property. Thus, an arrest—a seizure of a person—must be reasonable, both the cause and manner of the arrest. Two Supreme Court cases have shaped the current understanding of what constitutes unreasonable use of deadly force. In Tennessee v. Garner, the Court held that “[t]he use of deadly force to prevent the escape of all felony suspects, whatever the circumstances, is constitutionally unreasonable.” After Garner, two conditions typically had to be met for the use of deadly force to be constitutionally reasonable: (1) the officer must have “probable cause to believe that the suspect poses a significant threat of death or serious physical injury to the officer or others”; and (2) the officer must reasonably believe that deadly force is necessary to make the arrest or prevent escape.

The Supreme Court revisited the issue in 2007 in Scott v. Harris, which involved the use of deadly force to end a high-speed car chase. In Scott, the Court stressed that the reasonableness analysis is not an “on/off switch,” and that the particular facts of each case—“the use of a particular type of force in a particular situation”—must be considered in determining what is unreasonable under the Fourth Amendment. Accordingly, a court must balance the interests of the defendant against society’s interest in effectuating the particular arrest in question. Disparities between the current Fourth Amendment standard and state laws have created situations where a police officer’s use of deadly force may be legal according to state criminal law, and yet still violate the Constitution (making the officer civilly liable under federal law).

Questions for Review:

Q1. What are the differences between the common law and MPC rules justifying the use of deadly force in making an arrest? Which do you agree with? Why?

Q2. What are the policy motivations behind broader or narrower authority to use deadly force in preventing crimes and making arrests? What are the advantages and disadvantages to each? How would you amend the existing rules?

Q3. Do you agree with current constitutional doctrine that extends Fourth Amendment protections against law enforcement officers but not against private citizens?

Of Possible Interest:

I have written a few reflections on the events surrounding Ferguson (no extra credit for reading these).

“Hope in Ferguson,” Wash U. Voices (August 3, 2015)

“What is Truth in Ferguson and New York City?” Hedgehog Review Blog (December 17, 2014)

“Law and Violence,” Hedgehog Review Blog (November 26, 2014)

“Are We Ferguson?” CNN (August 21, 2014)

“Let’s Talk About Race,” St. Louis Post-Dispatch (August 14, 2014)