Categories of Homicide

Categories of Homicide

The three-way sort of killings reflects three different judgments the law can make about a person who has caused a death. In the first, the law regards the killing as the right thing to do, or at least as something it permits. In the second, the killing was not authorized, yet the person is not blameworthy enough to be punished. In the third, the killing is wrongful and the person is blameworthy. These judgments line up with the common-law categories: justifiable homicide for killings the law commands or authorizes, excusable homicide for killings in which a recognized defense eliminates liability, and criminal homicide for every other unlawful killing.¹ Each category gets its own subsection below, since the line between neighboring categories is where classification errors occur.

The third category is a residue, and that gives the scheme its logic. Criminal homicide takes in everything that is neither justified nor excused, so the three categories leave no gap, and every killing of one person by another has a place in them. A homicide problem therefore runs by elimination: ask first whether the law authorized the killing, then whether a recognized defense excuses it, and treat whatever remains as criminal. The word homicide by itself describes only an event, the killing of one human being by another, and carries no accusation. The offenses that fill the residual category are murder and manslaughter, and no crime exists that is simply called homicide.²

Self-defense is the principal doctrine in the justified category, and the rest of this chapter develops it. Its placement has a history. In United States v. Peterson the D.C. Circuit began from Blackstone's scheme, under which a homicide is treated as murder unless the law justifies it, excuses it on account of accident or self-preservation, or reduces it to manslaughter. The court described the defendant's claim that he acted to preserve himself as a claim of excused homicide and observed that no question of justifiable homicide in Blackstone's sense was presented.³ The vocabulary has drifted since then, and reference sources sometimes use justifiable and excusable interchangeably for a killing in self-defense.⁴ The conventional modern sorting treats a defender who actually faces an unlawful attack as justified, because the law authorizes the force used. A defender who reasonably but mistakenly believes force is necessary is sometimes better described as excused, since no real attack existed to authorize the force, and the closing sections of this chapter return to that defender. The sort begins with the first category, justifiable homicide.

Justifiable Homicide

Justifiable homicide is the first of the three categories, and it takes in killings that the law expressly commanded or authorized.⁶ The two verbs mark two strengths of legal backing. A command leaves the actor no choice, as when a lawful execution for a capital crime is carried out, while an authorization gives a permission the actor may or may not use, as when the law allows a killing to prevent a crime or to stop a criminal's escape.⁷ Killing in self-defense against the danger of death or serious bodily injury belongs in the same group, and it is the example around which the rest of this chapter is built.⁸ What these situations share is a source outside the defendant's own wishes: a rule of law, rather than the defendant's anger or conviction, makes the killing proper.

The law treats these killings as proper conduct and not as wrongs it has chosen to forgive, and the reason lies in how a legal system has to work. A system cannot coherently command or authorize an act and then punish the person who performs it. An order to carry out a sentence followed by a murder prosecution of the one who obeyed would contradict itself, and a person facing a knife could not tell whether the law was telling them to defend themselves or to submit. In the self-defense setting the law resolves the conflict by weighing the harms: the defender's life, which the attack puts at risk, counts for more than the harm done to the attacker. Because the act itself is judged lawful, the justified defender is acquitted outright, and the justification is a statement about what was done, not only about the state of mind of the person who did it. That feature is what distinguishes this category from excusable homicide, where the act was not authorized and the defendant escapes punishment for a different reason, taken up in the next subsection.

The two scenes differ in one respect that matters, which is whether the law authorized force at the moment D fired. Both defendants intended to kill, so intent to kill does not decide the category; the authorization does. The elements that make force authorized (what the defender must believe, how imminent the danger must be, and what kind of force is being resisted) are the subject of the next part of this chapter, so here the only point is how the classification works. One further caution concerns vocabulary. Reference sources sometimes treat the killing of an attacker in self-defense as justifiable and sometimes use the label excusable for the same killing.⁹ When a problem uses either word, look to the consequence the law attaches: if the law authorized the force, the killing is proper and the defender is acquitted, and that is what justifiable homicide means.

Excusable Homicide

Excusable homicide is the second of the three common-law categories. It covers killings for which the law recognized a defense that eliminated criminal liability even though the law had not authorized the act.¹¹ The category sits beside justifiable homicide and produces the same outcome, an acquittal, which is why the two are so easily blurred. The difference lies in what the law says about the act itself. A justified killing is one the law approves, while an excused killing is one the law declines to punish even though it does not approve.

The cleanest statement of that line comes from State v. Leidholm, which involved a wife who stabbed her sleeping husband after a night of drinking and violence between them. The North Dakota Supreme Court reversed her manslaughter conviction and, in reviewing the self-defense instructions, explained the difference between the two kinds of defense because the state's statutes treat self-defense as either justified or excused.¹² A justification, the court said, reflects society's judgment that the actual existence of certain circumstances makes proper and legal what would otherwise be criminal. An excuse openly admits that the conduct is criminal and forgives it because the actor believed that circumstances existed which would have justified the conduct, when in fact they did not.¹³ The sorting question follows directly: had the facts been as the actor supposed them, would the conduct have been justified? If the answer is yes but the facts were otherwise, the killing is excused rather than justified.

The law keeps the two ideas apart because they answer different questions. Justification asks whether the law permitted the conduct, and excuse asks whether the actor can fairly be blamed for it. Consider the defender whose reasonable belief in an attack turns out to be wrong. The supposed attacker was not in fact dangerous, so the law cannot call the killing the right thing to do, and it has no wish to announce that anyone who looks threatening may be killed. Yet the defender acted as a careful person would, and a careful person cannot be deterred from acting carefully. Punishment would therefore teach nothing, and it would expose every sensible person who responds to a frightening situation to conviction whenever appearances happen to deceive. Making the defense complete in both settings removes that exposure.

Self-defense shows how the label can move. The widely accepted rule does not demand that force be truly necessary. It asks whether the defender honestly and reasonably believed force was necessary.¹⁴ When the belief is well founded because a real attack was under way, the defender did the right thing and the killing is justified. When the belief is reasonable but mistaken, the force arguably was not the right thing to do, and the more precise description is excuse.¹⁵ Courts and commentators nonetheless call self-defense a justification in both settings, and the label never changes the result: a defendant who meets the requirements is entitled to an acquittal.¹⁶ Excuse is a complete defense, so the reasonable but mistaken defender is acquitted outright rather than convicted of a lesser offense. How reasonable the mistake must be is developed in the mistake section near the end of this chapter, so here it is enough to hold that a reasonable belief carries the defender out of liability.

The distinction once carried real consequences. In Blackstone's scheme, killing in self-preservation was excusable homicide, grounded in the universal instinct to save one's own life before another's.¹⁷ English law treated even a reasonable killing in self-defense as an excuse only, and the excused killer faced forfeiture of property and at times a penal sentence, until a statute of 1532 enlarged the justification defense to cover deadly force reasonably used in self-defense.¹⁸ That history helps explain why later vocabulary drifted. A standard legal dictionary defines excusable homicide as a killing resulting from a lawful act committed without intent to harm, which is the accidental killing, and then cross-refers to justifiable homicide.¹⁹ When a problem uses either word, the safer course is to look at substance. If the law authorized the force, the act was proper. If the law concedes the act was wrongful and relieves the actor anyway, the killing is excused, and the actor is acquitted in either case. A killing that fits neither category is criminal homicide, the residual category taken up next.

Criminal Homicide

Criminal homicide is the third category, and it is defined by subtraction: it takes in every unlawful killing that is neither justified nor excused.²¹ Because the category has no entry conditions of its own, a killing lands here whenever the law neither authorized it nor recognized a defense for it. That design sets up a presumption that one person's killing of another is wrongful unless the actor can fit it into a protected category. A defender who cannot meet the conditions of a defense cannot borrow its protection. Each limit developed later in this chapter (the unlawful-force requirement, the restrictions on deadly force, the aggressor rule, and the retreat duty) works by pushing a killing out of the justified and excusable groups and into this one.

The category names a classification, and the crimes inside it carry the grades. Under the Model Penal Code, criminal homicide is the act of purposely, knowingly, recklessly, or negligently causing the death of another human being, so the mental state separates the serious offenses from the lesser ones.²² Traditional law reaches a similar grading by a different route. The paradigm of murder is a deliberate killing without legal justification or excuse. Manslaughter takes in killings committed in circumstances that substantially mitigate their intentional aspect, along with killings that are not intentional at all.²³ Landing in criminal homicide therefore settles only that the killing is wrongful. A second step decides how severely the law condemns it.

The two scenes share an argument and an intentional killing, and they separate on a single fact: whether the force D used answered an attack that the law allows deadly force to meet. In the first scene D answered a shove with a knife, so the claim of defense never gets started. When a self-defense claim fails, the killing stays in criminal homicide, because the defense never removed it from that category. A failed claim does not always draw the harshest label, though. Because the category is graded, some killings in which the defender acted from real fear can be mitigated instead of condemned in full, and the last section of this chapter takes up that middle ground between acquittal and a murder conviction.

Whether a given killing escapes this category depends on whether the law authorized the force at the moment it was used. The next part of this chapter therefore turns to the basic self-defense rule, which asks what the defender believed, whether force was immediately necessary, and whether the force being resisted was unlawful.