What does California law say about using a firearm in self-defense at home?

Penal Code 197 lists when homicide by any person is justifiable. Three of its four cases bear on home defense:

1. When resisting an attempt to murder any person, to commit a felony, or to do some great bodily injury upon any person.
2. In defense of habitation, property, or person against someone who "manifestly intends or endeavors, by violence or surprise, to commit a felony," or who tries "in a violent, riotous, or tumultuous manner" to enter a habitation to offer violence to a person inside.
3. In the lawful defense of the person, or of a spouse, parent, child, or certain others, when there is reasonable ground to apprehend a design to commit a felony or do great bodily injury, and imminent danger of it being accomplished. A person who was the assailant or engaged in mutual combat "must really and in good faith have endeavored to decline any further struggle" first.

Penal Code 198 limits the second and third cases. The circumstances "must be sufficient to excite the fears of a reasonable person, and the party killing must have acted under the influence of such fears alone."

Penal Code 198.5 says a person who uses force intended or likely to cause death or great bodily injury within their residence "shall be presumed to have held a reasonable fear of imminent peril of death or great bodily injury to self, family, or a member of the household" when its conditions are met.

The jury instruction on this presumption, CALCRIM No. 3477, breaks it into four parts:

1. An intruder unlawfully and forcibly entered or was entering the defendant's home.
2. The defendant knew or reasonably believed that this was happening.
3. The intruder was not a member of the defendant's household or family.
4. The defendant used force intended to or likely to cause death or great bodily injury to the intruder inside the home.

The presumption can be overcome. The instruction says "The People have the burden of overcoming this presumption," which means proving the defendant did not have a reasonable fear of imminent death or injury when using force against the intruder.

Under CALCRIM No. 505, a defendant acted in lawful self-defense or defense of another if:

1. The defendant reasonably believed that they or someone else was in imminent danger of being killed or suffering great bodily injury.
2. The defendant reasonably believed that the immediate use of deadly force was necessary to defend against that danger.
3. The defendant used no more force than was reasonably necessary to defend against that danger.

The instruction adds two points:

• "Belief in future harm is not sufficient, no matter how great or how likely the harm is believed to be."
• If the defendant's beliefs were reasonable, "the danger does not need to have actually existed."

CALCRIM No. 506 covers a killing to defend a person inside the defendant's home. The defendant must have reasonably believed that they were defending the home against a person who intended or tried to commit a forcible and atrocious crime, or who violently tried to enter intending to commit an act of violence against someone inside. The defendant must also have reasonably believed the danger was imminent and deadly force was necessary, and must have used no more force than was reasonably necessary.

The Judicial Council's instructions say there is not. CALCRIM Nos. 505, 506, and 3470 each include this optional paragraph: "A defendant is not required to retreat. He or she is entitled to stand his or her ground and defend himself or herself and, if reasonably necessary, to pursue an assailant until the danger" has passed. "This is so even if safety could have been achieved by retreating" (CALCRIM). The limits on necessity and reasonable force still apply.

Penal Code 197 mentions "defense of habitation, property, or person." The bench notes to CALCRIM No. 506 explain that the California Supreme Court read that language narrowly in People v. Ceballos (1974): burglaries that "do not reasonably create a fear of great bodily harm" are not sufficient "cause for exaction of human life," and a person must be at risk of great bodily harm or an atrocious felony for a homicide to be justified (CALCRIM No. 506, Bench Notes).

In a criminal trial where self-defense is raised, "The People have the burden of proving beyond a reasonable doubt that the [attempted] killing was not justified," and if they do not meet it, the jury must find the defendant not guilty (CALCRIM No. 505). Penal Code 199 says a person whose homicide appears justifiable or excusable must be "fully acquitted and discharged."

These rules describe a trial. They do not describe whether police will investigate, whether a prosecutor will file charges, or how a civil claim would be decided.