Justifiable homicide

The United States' concept of justifiable homicide in criminal law stands on the dividing line between an excuse, justification and an exculpation. In other words, it takes a case that would otherwise have been a murder or another crime representing intentional killing, and either excuses or justifies the individual accused from all criminal liability or treats the accused differently from other intentional killers.

Explanation
The normal rule in the criminal law is that those accused of crime should be convicted of an offense only if they have committed the actus reus (the Latin for "guilty act") of an offense, accompanied by the necessary mens rea (the Latin for "guilty mind") element. Thus, if one person has killed another, intending to do so, the normal consequence would be a conviction for murder. But, for a variety of different public policy reasons, societies over the centuries have considered it morally acceptable and/or merely expedient for one person to kill another and to treat this killing as "justifiable" in a number of different situations. Thus, the Laws of Solon forming part of early Athenian law, provided that if an accused pleaded that they were justified in killing another, their case would be tried in a dedicated court called the Delphinion where, for example, it was considered justifiable homicide to kill an adulterer caught in the act or a burglar caught in the act at night. These exceptions to liability match the modern concepts of provocation and defense of property and reflect the fact that, although the terminology of justification may change over the centuries, the human concepts of jealousy and the rights of ownership remain reasonably consistent as potential excuses.

In deciding when intentional killings should be treated as "justifiable", governments are balancing different sets of interests. On the one hand, states usually accept some form of practical responsibility to protect their citizens from harm. In more modern times, this reflects a social contract where allegiance is rewarded by the provision of policing and other civil defense systems, and the apparatus of redress for injuries suffered through a court system. In the United Nations Universal Declaration of Human Rights, Article 3 states that everyone has the right to life, liberty and security of person, and many constitutions offer protection for "life" which, presumably, even applies to those who have broken the law. Yet, more modern cultures also value and respect individual autonomy, and wish to avoid unduly restricting an individual's freedom of action and refrain from interfering in a citizen's life unless it is absolutely necessary. Where the balance is struck will be reflected in which situations are allowed to become excuses and result in an immunity, and those situations which merely exculpate, i.e. allow special treatment either by reducing the charge to one less serious, or by reducing the sentence. Hence, in eighteenth century English law, it was considered a justifiable homicide if a husband killed a man "ravishing" or raping his wife (Blackstone, Wm. at p391), but most modern English law jurisdictions treat this as only a circumstance that will mitigate murder to a conviction for manslaughter. In other words, the socialization of modern men is supposed to result in less violent responses to provocations.

Common excusing conditions
Potentially excusing conditions common to most jurisdictions include the following.
 * 1) Where a state is engaged in a war with a legitimate casus belli, a soldier from one of the combatant states may lawfully kill a soldier in the army of the opposing state so long as that soldier has not surrendered. This principle is embedded in public international law and has been respected by most states around the world. Thus, if there is no formal declaration of war or the casus belli is not legitimate, all those who engage in the fighting and kill combatants could theoretically be prosecuted. Otherwise, protecting the national interest against external aggressors will be considered an excuse on utilitarian grounds, i.e. the greatest public good will be derived from the defeat of the enemy.
 * 2) Where a state operates a system of capital punishment, all those who may be involved are excused from liability. This usually includes the judge who passes sentence, the prison guards who deliver the condemned person to the place of execution and those who carry out the sentence.
 * 3) Many countries agree that it may be lawful for a citizen to repel violence with violence to protect his or her own or another's life and limb, or to prevent sexual assault. However, there is less agreement on the extent to which it is ever justifiable to kill the attacker. There are usually tests based on the proportionality of the response to the attack. Thus, there may be exculpation if the level of force used in defense matches the force threatened and the "winner" of the conflict first retreated or showed a clear intention not to fight (assuming this was possible in the time available).
 * 4) Some countries agree that it may be lawful for a citizen to resort to violence to protect valuable property, usually defined as one's own.
 * 5) The idea of a crime of passion, in which death results from the "heat of the moment," is now considered a part of the defense of "provocation" against a charge of murder. This recognizes that all individuals may suddenly and unexpectedly lose control when words are spoken or events occur but, again, states differ on the extent to which this should be allowed to excuse liability or merely mitigate to a lesser offense such as manslaughter.
 * 6) The doctrine of necessity allows, for example, a surgeon to separate conjoined twins, killing the weaker twin to save the other.
 * 7) In the United States, the 2005 Unborn Victims of Violence Act defined human fetuses as "unborn children" for the first time, recognizing all fetuses as equal holders of general human rights and formally defining feticide as murder (under USC §1111). However, the law retained explicit exceptions which prohibit the prosecution "of any person for conduct relating to an abortion," "of any person for any medical treatment," or "of any woman with respect to her unborn child," thereby preserving abortion rights in the United States under a justifiable homicide framework.
 * 8) Several countries, such as the Netherlands, Belgium, Switzerland, Japan, and the US states of Oregon and Washington allow both active and passive euthanasia by law, if justified.
 * 9) There is a strand of authority that potentially permits police or other law enforcement officers to use force to protect others from harm. This is another example of utilitarianism in that it may be necessary to prejudice the few to benefit the many. But, in many states, there is a presumption of innocence before the criminal case comes to trial. If deadly force is used to arrest a suspect, this permanently infringes on the citizen's human rights before a court has found guilt, which would be particularly unfortunate in those states that have abolished the death penalty. In South Africa, §49 Criminal Procedure Act used to provide:
 * (2) Where the person concerned is to be arrested for an offense referred to in Schedule 1 or is to be arrested on the ground of having committed such an offense, and the person authorized under this Act to arrest or to assist is arresting him cannot arrest him or prevent him from fleeing by other means than killing him, the killing shall be deemed to be justifiable homicide.
 * This has now been amended by §7 Judicial Matters Second Amendment Act 122 of 1998:
 * (2) If any arrestor attempts to arrest a suspect and the suspect resists the attempt, or flees, or resists the attempt and flees, when it is clear that an attempt to arrest him or her is being made, and the suspect cannot be arrested without the use of force, the arrestor may, in order to effect the arrest, use such force as may be reasonably necessary and proportional in the circumstances to overcome resistance or to prevent the suspect from fleeing: Provided that the arrestor is justified in terms of this section in using deadly force that is intended or is likely to cause death or grievous bodily harm to a suspect, only if he or she believes on reasonable grounds-
 * (a) that the force is immediately necessary for the purpose of protecting the arrestor, any person lawfully assisting the arrestor or any other person from imminent or future death or grievous bodily harm;
 * (b) that there is a substantial risk that the suspect will cause imminent or future death or grievous bodily harm if the arrest is delayed; or
 * (c) that the offence for which the arrest is sought is in progress and is of a forcible and serious nature and involves the use of life threatening violence or a strong likelihood that it will cause grievous bodily harm.

United States
A non-criminal homicide, usually committed in self-defense or in defense of another, may be called in some cases in the United States. A homicide may be considered justified if it is done to prevent a very serious crime, such as rape, armed robbery, manslaughter or murder. The assailant's intent to commit a serious crime must be clear at the time. A homicide performed out of vengeance, or retribution for action in the past, would generally not be considered justifiable.

In cases of self-defense, the defendant should generally obey a duty to retreat if it is possible to do so. In the states of Alabama, Alaska, Arizona, California, Colorado, Connecticut, Florida, Georgia, Hawaii, Indiana, Kentucky, Louisiana, Maine, Maryland, Massachusetts, Michigan, Mississippi, Missouri, Montana, New Jersey, North Carolina, Ohio, Oklahoma, Oregon, Rhode Island, South Carolina, Tennessee, Texas, West Virginia, Washington, Wyoming and other Castle Doctrine states, there is no duty to retreat in certain situations (depending on the state, this may apply to one's home, business, or automobile, or to any public place where a person is lawfully present). Preemptive self-defense, cases in which one kills another on suspicion that the victim might eventually become dangerous, is considered criminal, no matter how likely it is that one was right. Justifiable homicide is a legal gray area, and there is no clear legal standard for a homicide to be considered justifiable. The circumstances under which homicide is justified are usually considered to be that the defendant had no alternative method of self-defense or defense of another than to kill the attacker.

Two other forms of justifiable homicide are unique to the prison system: the death penalty and preventing prisoners from escaping. To quote the California State Penal Code (state law) that covers justifiable homicide:


 * 196. Homicide is justifiable when committed by public officers and those acting by their command in their aid and assistance, either--


 * 1. In obedience to any judgment of a competent Court; or,


 * 2. When necessarily committed in overcoming actual resistance to the execution of some legal process, or in the discharge of any other legal duty; or,


 * 3. When necessarily committed in retaking felons who have been rescued or have escaped, or when necessarily committed in arresting persons charged with felony, and who are fleeing from justice or resisting such arrest.

Although the above text is from Californian law, most jurisdictions have similar laws to prevent escapees from custody.