14.3 Self-Defense & Defense of Others (Tort)
Key Takeaways
- A defendant may use force reasonably necessary to protect against an imminent threatened battery, and a reasonable mistake about the existence of the threat does not defeat the privilege.
- Force must be proportionate, so deadly force is privileged only against a threat of death or serious bodily harm.
- The modern majority imposes no duty to retreat before using deadly force, while the Restatement minority requires retreat where it can be accomplished safely and never inside one's own home.
- The privilege is confined to preventing harm, so retaliation after the threat has ended is not self-defense.
- Most courts allow defense of others whenever the intervenor reasonably believes the person aided would have been privileged to defend themselves.
Self-Defense & Defense of Others (Tort)
Doctrinal Foundation: Unlike consent, which derives from the plaintiff's willingness to accept an invasion, the privileges of self-defense, defense of others, defense of property, and recapture of chattels are justification defenses grounded in an actor's legal right to prevent an unlawful interference with personal safety or possessory interests. On the California FYLSE, examiners evaluate your mastery of the dual subjective and objective reasonableness test in self-defense, the distinction between deadly and non-deadly force, the absence of a civil duty to retreat, the jurisdictional split between the majority "reasonable appearance" rule and the minority "alter ego" doctrine in third-party defense, the absolute prohibition against lethal mechanical traps under Katko v. Briney, and the strict "action at peril" rule governing recaption of chattels.
I. Self-Defense: Elements, Proportionality & Limitations
Self-defense privileges an individual to use reasonable physical force to prevent an imminent, unprivileged battery or other unlawful physical invasion threatened by an aggressor.
1. The Dual Reasonableness Standard
To establish the privilege of self-defense, the defendant must satisfy two distinct requirements:
- Subjective Honest Belief: The defendant must genuinely and subjectively believe that unlawful physical force is about to be inflicted upon them; and
- Objective Reasonable Belief: A reasonable, prudent person in the defendant's position, possessing the same physical characteristics and facing the same external circumstances, would have held that belief.
[!IMPORTANT] The Reasonable Mistake Rule: An honest, objectively reasonable mistake of fact does not forfeit the privilege of self-defense. If an adversary reaches rapidly into their jacket pocket while shouting death threats, and pulls out a realistic metallic replica pistol that looks identical to a semiautomatic firearm, a defendant who strikes the adversary in reasonable apprehension of death is fully privileged. The mistake of fact was reasonable.
2. Proportionality & The Threshold of Deadly Force
The defensive force employed must be strictly proportional to the threatened invasion:
- Non-Deadly Force: An actor is privileged to use reasonable non-deadly force to repel an imminent, non-deadly battery or offensive touching. An actor cannot strike someone with a baseball bat or iron wrench in response to a minor verbal taunt or an open-handed slap.
- Deadly Force: Defined as force intended or reasonably likely to cause death or serious, life-threatening bodily injury. Deadly force is privileged only if the defendant reasonably believes that the attacker is about to inflict imminent death or serious bodily injury.
- Imminence Requirement: The threat must be immediate—happening now or in the next immediate second. Self-defense cannot justify a preemptive strike against a remote threat ("I will return tomorrow to beat you"), nor can it justify retaliatory violence after an attacker has turned, surrendered, dropped their weapon, or fled.
3. The Duty to Retreat in Civil Tort Law
Unlike the sharp division in criminal law between "duty to retreat" and "stand your ground" jurisdictions, the uniform rule in intentional torts civil self-defense is that an actor has no duty to retreat before employing lawful defensive force. Even when facing deadly force, a civil defendant is generally entitled to stand their ground and defend themselves with proportional force, provided they did not provoke the confrontation.
4. The Initial Aggressor Doctrine
An initial aggressor—one whose unlawful conduct, physical assault, or menacing provocation initiated the conflict—cannot claim self-defense. However, the initial aggressor's privilege is restored under two narrow exceptions:
- Withdrawal and Communication: The initial aggressor completely desists from the attack, retreats from the encounter, and clearly communicates their abandonment of the conflict to the other party; or
- Sudden Lethal Escalation: The adversary unlawfully and abruptly escalates a minor, non-deadly altercation into a lethal confrontation (e.g., in response to a minor push, the adversary pulls a loaded firearm and begins shooting). The initial aggressor may then use proportional defensive force to preserve their life.
II. Defense of Third Persons (Defense of Others)
An intervenor is privileged to use reasonable force to defend a third party against an imminent unlawful attack to the same extent the third party would be privileged to protect themselves.
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[MAJORITY: REASONABLE APPEARANCE] [MINORITY: "ALTER EGO" RULE]
- Judged by objective appearance at time of intervention - Intervenor "steps into the shoes" of third party
- Protects REASONABLE MISTAKES of fact - Intervenor acts strictly AT THEIR OWN PERIL
- If intervenor reasonably believed victim was innocent, - If third party was initial aggressor or resisting
intervenor is PRIVILEGED even if mistaken lawful arrest, intervenor is STRICTLY LIABLE
1. The Majority Rule: Reasonable Appearance Standard
Under the prevailing modern rule applied in California and multistate bar exams, the intervenor's privilege is measured by the objective appearance of the situation at the moment of intervention. If the intervenor honestly and reasonably believes the third party is the innocent victim of an unlawful assault, the intervenor is privileged to use reasonable force to defend them, even if that belief is mistaken.
- Example: An intervenor sees a plainclothes police officer tackling an unarmed citizen without identifying themselves or displaying a badge, and reasonably believes a violent mugging is underway. The intervenor is privileged in tort if the mistake was objectively reasonable under the circumstances.
2. The Minority Rule: "Alter Ego" (Steps into the Shoes)
Under the traditional common-law alter ego rule, the intervenor acts strictly at their own peril and acquires only the actual legal rights of the person being defended. If the person defended was in fact the initial aggressor or had no legal right to resist (such as an individual resisting a lawful arrest), the intervenor has no privilege and is strictly liable for battery, regardless of how reasonable the intervenor's mistaken belief appeared.
A pedestrian reasonably but mistakenly believes an approaching stranger is reaching into a coat to draw a weapon, and strikes the stranger once to prevent the perceived attack. The stranger was in fact reaching for a mobile phone and sues for battery. What is the result?
A bystander sees a plainclothes police officer forcibly restraining a struggling man and, reasonably believing the man is being assaulted by a mugger, tackles the officer. The officer sues the bystander for battery. Under the modern majority rule, is the bystander liable?