wikipedia | In the criminal law, the duty to retreat is a specific component which sometimes appears in the defense of self-defense, and which must be addressed if the defendant is to prove that his or her conduct was justified. In those jurisdictions where the requirement exists, the burden of proof is on the defense to show that the defendant was acting reasonably. This is often taken to mean that the defendant had first avoided conflict and secondly, had taken reasonable steps to retreat and so demonstrated an intention not to fight before eventually using force.
Some U.S. jurisdictions require that a person retreat from an attack, and allow the use of deadly force in self-defense only when retreat is not possible or when retreat poses a danger to the person under attack. The duty to retreat is not universal, however. For example, police officers are not required to retreat when acting in the line of duty. Similarly, some courts have found no duty to retreat exists when a victim is assaulted in a place where the victim has a right to be, such as within one's own home. The Model Penal Code suggests statutory language that also recognizes an exception to the usual duty to retreat when the victim of the attack is in his or her own dwelling or place of work. It is common to exempt a person's home or car from the duty to retreat, known as the castle doctrine.
Many states employ stand your ground laws that do not require an individual to retreat and allow one to match force for force, deadly force for deadly force. The Washington State Supreme Court, for example, has ruled "that there is no duty to retreat when a person is assaulted in a place where he or she has a right to be."