Here's a summary and interpretation from one state. Research the applicable statutes where you reside.
The law establishes special rules for using deadly force to defend one's self or another person. Specifically, the law prohibits anyone from using such force unless he or she (1) reasonably believes that the attacker is using or about to use deadly physical force or inflicting or about to inflict great bodily harm and (2) knows he or she cannot avoid the need to use deadly force by retreating. But the law specifies that a person does not have to retreat before using deadly force if he or she is in his or her dwelling or workplace.
A related statute establishes the circumstances under which someone can use force to defend his or her premises. Under this law, a person who possesses or controls property, or has a license or privilege to be in or on it, can use reasonable physical force when and to the extent he or she reasonably believes it to be necessary to stop another from trespassing or attempting to trespass in or upon it.
Just as in the case of using deadly force for self defense or a defense of another person, the law establishes special rules for using deadly force in defense of premises. Specifically, the law allows a person who possesses or controls property, or has a license or privilege to be in or on it, to use deadly physical force only:
1. to defend himself, herself, or someone else if he or she reasonably believes that the attacker is using or about to use deadly physical force or inflicting or about to inflict great bodily harm;
2. when he or she reasonably believes it is necessary to prevent the trespasser from attempting to commit arson or any violent crime, or
3. to the extent he or she reasonably believes it is necessary to stop someone from forcibly entering his or her dwelling or workplace, and for the sole purpose of stopping the intruder.
Generally, the “castle doctrine” provides that someone attacked in his or her home can use reasonable force, which can include deadly force, to protect his or her or another's life without any duty to retreat from the attacker. It is defined differently in different states.
The defense of self-defense is available to a defendant faced with the intentional torts of civil assault and battery, as long as there is sufficient evidence in support of that defense. This defense is also available in lawsuits where the plaintiff claims it was the defendant's negligence that caused his or her injuries because the defendant used more force than was reasonably necessary under the circumstances. This defense will prevail only if the jury (or judge in a non-jury trial) concludes that the defendant acted reasonably under the circumstances with respect to (1) the need to use force and (2) the degree of force actually used.
In recent years, a number of states have adopted or considered bills referred to as “castle doctrine” bills. We found 20 states that adopted a “castle doctrine” bill in the last three years. These states are: Alabama, Alaska, Arizona, Florida, Georgia, Idaho, Indiana, Kansas, Kentucky, Louisiana, Michigan, Mississippi, Missouri, Oklahoma, South Carolina, South Dakota, Tennessee, Texas, West Virginia, and Wyoming. The enacted bills in all but three of these states (Indiana, Kansas, and South Dakota) explicitly deal with civil as well as criminal liability.
These bills have also been called “stand your ground” bills because they often eliminate the duty to retreat from any place where the person is legally allowed to be.
Many of these states substantially changed their self-defense statutes by:
1. expanding the definition of residence where there is no duty to retreat before using deadly force to include a person's motor vehicle, porch;
2. adopting no duty to retreat before applying deadly force if the person using the force had the right to be where he or she was;
3. creating a presumption that an assailant intends to commit an unlawful act by force or by violence;
4. creating a presumption of necessity regarding the use of deadly force to repel the threat;
5. creating a presumption of reasonableness regarding the level of force used;
6. granting immunity from both civil actions and criminal prosecution;
7. imposing a prohibition against arrest; and
8. directing courts to award court costs, attorney fees, loss of income, and other expenses to the defendant.
This will give you a decent understanding of the concepts. Good luck.
