One of the fundamental concepts of any free, democratic society is the idea of the individual's right to self-defense -- that one may use any means at one's disposal to protect one's person or property from assault from another. However, there are important stipulations and limitations that define the allowable limits an individual may approach -- and crossing over these limits can make the difference between being a justified victim and an outright criminal.
According to the legal definition of self-defense, the use of force is allowed when an individual "reasonable believes that it is necessary for the defense of oneself or another against the immediate use of unlawful force. However, a person must use no more force than appears reasonably necessary in the circumstances." This means that one can only employ enough force to remove the present threat. For example, one may only use lethal force in self-defense (firearms, weapons, etc.) if one reasonably believes that only lethal force will prevent death or "great" bodily harm.
Interestingly, the mere threat of force is not sufficient to allow forceful self-defense if there are measures one can take to prevent the attack without force. This can include quickly locking a door, running away, or taking other avoidance measures. Further, if these measures are not sufficient to protect one against an attack (on one's person or property), one may use only enough force to repel the attack. In specific this is important because if, after the attack has been repelled, one continues to aggress against the assailant, the victim may become the unlawful aggressor.
Of course, the most common example of this stipulation on the allowable limit of self defensive action is given in the "home invasion scenario," where an unarmed person goes into a home to commit robbery, does not threaten or harm anyone, yet encounters during the home invasion the owner or occupants of the home. If that home owner could, again, reasonably overpower, chase away, or detain that individual, he is required to perform those actions rather than resorting to more damaging or lethal measures. For example, if the intruder were to be surprised by the homeowner, and was successfully chased out of the house (the "chasing" the act of self-defense), the homeowner may not legally shoot at the fleeing offender -- this is because the immediate threat has been removed.
A real world example of this limitation occurred this month in Knowlton Township, New Jersey, when "A Middlesex County man who stole what he thought was an unoccupied minivan from a truck stop was surprised to discover a man sleeping in the back seat, and even more surprised when the man shot at him, police said."
According to reports, the perpetrator sought to steal a running van from a rest stop, jumped in, and began to drive. Unfortunately for him, however, he did not realize that the owner was simply sleeping in the back. When the owner awoke and realized what happened, he pulled out a gun, pointed it at the perpetrator, and ordered him to stop the car and get out. When he did, however, the owner fired at the retreating carjacker, missing him. According to the police report, the carjacker was charged with "carjacking, burglary and theft, while the victim was charged with aggravated assault against the carjacker for shooting at him while he fled.
However, although an individual may not take retaliatory measures against an attacker once the imminent threat is removed, it is important to note that the victim is not required to expend excessive thought in determining the extent of the threat posed before acting, even with lethal force. This means that when an attack is perpetrated, the victim may not be reasonably expected to know how much bodily danger he or she is in. After all, many would assume that the intent of a home invader is to do serious harm to the individual. Therefore, a person is not required to "weigh with great nicety the probable extent of the attack, and he may use the most violent means against his assailant, even to the taking of his life."
In addition to protecting oneself, the law allows so called "near relations" to stand in "mutual and reciprocal defense." In this case, if another person is threatened, one can take action against the attacker:
The party attacked may undoubtedly defend himself, and the law further sanctions the mutual and reciprocal defense of such as stand in the near relations of husband and wife, patent and child, and master and servant. In these cases, if the party himself or any of these his relations, be forcibly attacked in their person or property, it is lawful for him to repel force by force, for the law in these cases respects the passions of the human mind, and makes it lawful in him, when external violence is offered to himself, or to those to whom he bears so near a connection, to do that immediate justice to which he is prompted by nature, and which no prudential motives are strong enough to restrain.
Although the law seems on the surface to be quite clear concerning the limits of self-defense action, the origins of the current legal understanding of those limits evolved through the deliberation of many cases. According to the American Journal of Criminal Law, "The self-defense cases: Howe the United States Supreme Court confronted a hanging judge in the nineteenth century and taught some lessons for jurisprudence in the twenty-first:"
From 1893 to 1896, the United States Supreme Court handed down a series of decisions involving self-defense and the carrying and use of firearms for self- defense. These cases laid the foundation for a 1921 opinion, authored by Justice Oliver Wendell Holmes, that became the most important armed self- defense case in American legal history, upholding and extending the right to armed self- defense. In these Self-Defense Cases, the Supreme Court fought out a bitter confrontation with Federal District Judge Isaac Parker, the presiding judge in all but one of the cases, and a judge who is much admired today by Chief Justice William Rehnquist. (Kopel, 2000)
In particular, the court considered some interesting cases, including B. Starr v. United States, in which the issue was considered whether "a citizen use deadly force to resist an assault by a peace officer who has not announced that he is a peace officer." (The answer was yes), as well as the issue of whether prior threats by an attacker are relevant to the use of deadly force, Wallace v. United States (they are).
In contemporary times, courts have considered interesting issues as well, including the famous "booby trap" topic -- or if it is legal to set deadly booby traps to severely injure or kill expected (by previous incident experience) intruders regardless of threat to personal safety. Here one might, after experiencing several home invasions, out of frustration, rig a shotgun or other device to seriously injure or kill an invading individual. Not only is this dangerous due to its indiscriminant danger (a booby trap could kill anyone, including aid workers, firefighters, police, etc.), but it is illegal even if it kills or injures a trespasser. This is because the individual may not be home during the invasion, and, if so, is not allowed to "defend" oneself in absentia.
Further, another example of contemporary self-defense issues arise around the problem of domestic violence -- specifically in cases where women have killed alleged abusive husbands in order to prevent further serious physical abuse, injury, or death. Indeed, there is significant legal difference of opinion in considering cases where spouses kill out of "anticipatory fear" of abuse, especially when the abuse has persisted for many years. In these cases in particular, feminist groups argue that the "reasonableness" clause…