Black-letter propositions
- 01
Consent may be express, apparent, or implied by custom, but is limited by capacity, fraud about an essential matter, duress, public policy, and scope.
- 02
Self-defense permits reasonably necessary force against imminent tortious force; reasonable mistake is generally allowed.
- 03
Defense of others follows reasonable appearance in modern law.
- 04
Reasonable nondeadly force can protect property after demand when feasible; deadly mechanical devices cannot protect property alone.
- 05
Public necessity is a complete defense to property torts; private necessity is incomplete and requires payment for actual damage while preserving a privilege to remain.
- 06
Legal authority protects reasonable conduct within official privilege.
Use this attack sequence under time
Frame the issue
Identify triggering threat or permission.
Resolve the next checkpoint
Classify force or invasion.
Resolve the next checkpoint
Test subjective and objective reasonableness.
Resolve the next checkpoint
Check scope and mistake.
Finish the conclusion
State complete or incomplete defense and damages.
Common wrong turns
- Consent to one act is not consent to a substantially different act.
- An initial aggressor must withdraw or face escalation before reclaiming defense.
- Private necessity defeats ejectment but not compensation for actual harm.
Worked example
A boater ties to a private dock during a sudden life-threatening storm and damages it.
Private necessity privileges use of the dock, so the owner cannot eject the boater during danger, but the boater must pay actual damage.
Practice this topic
Consent and justification
Cornell says consent, whether express or implied, such as participating in a sport, is a defense to civil battery. Justification is a defense that exempts a defendant from liability because the actions were not wrong, and self-defense is the example: use of force to protect oneself from an attempted injury by another. If justified, it is a defense in criminal and tort law.
Cornell's New York example states the elements: a reasonable belief that force is necessary against unlawful physical force, an imminent danger, proportionate force, and the defender not being the initial aggressor.
Others, deadly force and necessity
Defense of others is a defense for using reasonable force to protect a third party from another who threatens force. Some jurisdictions require a special relationship, but most require only a reasonable belief that defense was necessary. Cornell defines deadly force as force likely to cause death or serious bodily injury.
The necessity defense applies where conduct cannot be avoided and prevents a more serious harm, the lesser of two evils. For each defense, state the privilege, its scope and its limits, since force beyond the privilege becomes a tort.
Frequently asked questions
What is the controlling rule for consent, self-defense, property defense, necessity, and authority?+
Privileges require consent or reasonable necessity within scope and often determine both liability and whether damages remain payable.
How should I analyze consent, self-defense, property defense, necessity, and authority on the bar exam?+
Identify triggering threat or permission. Classify force or invasion. Test subjective and objective reasonableness. Check scope and mistake. State complete or incomplete defense and damages.
Is consent a defense to battery?+
Yes. Cornell says consent, express or implied, such as by participating in a sport, is a defense to civil battery.
What is self-defense on the bar exam?+
The use of force to protect oneself from an attempted injury by another, a defense in criminal and tort law if justified.
What limits apply to self-defense?+
The danger must be imminent, the force proportionate, and the defender cannot be the initial aggressor, per the New York example Cornell gives.
Does defense of others require a special relationship?+
Some jurisdictions require one, but most require only a reasonable belief that it was necessary to defend the third party.
What is the necessity defense?+
A defense where the conduct prevents a more serious harm and could not be avoided, the lesser of two evils, according to Cornell.