While California does not have a "Stand Your Ground Law," there are laws that can provide a level protection to those who attempt to defend themselves.
The “Stand Your Ground Law” law provides justification in criminal cases for defendants to use force without retreating to protect themselves or others against threats or perceived threats. In California, there is something similar known as the Castle Doctrine.
The Castle Doctrine
The Castle Doctrine is state law and allows a resident to use force against a criminal that forces their way into or breaks into their home.
The resident needs to have a reasonable fear of imminent death or great bodily injury to himself or others in his household. This resident must also know or have reason to believe that unlawful and forcible entry occurred.
Judicial Council of California Criminal Jury Instructions
The Judicial Council of California provides instructions to criminal juries. CALCRIM instructions #505 and #506 are categorized under Justifications and Excuses for homicide.
CALCRIM #505. Justifiable homicide: Self Defense or Defense of Another
Instruction #505 states that a defendant is not guilty of murder if he was justified in killing or attempting to kill someone in self-defense or in defense of another.
A defendant has to have a reasonable belief that he or someone else was in “imminent danger of being killed or suffering great bodily injury”. Additionally, the defendant must also have believed that deadly force was necessary for defense and used no more force than necessary.
Belief that future harm may come is not sufficient to justify a killing or attempted killing.
CALCRIM #506. Justifiable Homicide: Defending Against Harm to Person Within Home or on Property
Defendants are not guilty of a murder charge or manslaughter if he killed or attempted to kill in order to defend himself in his home.
A defendant who reasonably believed that he was defending his home against someone trying to commit a “forcible and/or atrocious crime” or who tried to enter the home to commit an act of violence.
Defendants must also have believed that they were in imminent danger, reasonably believed that use of deadly force was necessary for defense, and used no more force than necessary to defend against the danger.
Within instruction #506, it states that a defendant is not required to retreat, can defend himself, and, if necessary, pursue an assailant until the danger of death or bodily injury has passed.
Like instruction #505, belief in future harm is not sufficient for justification.