Is It Legal to Protect Someone Else During an Assault?

Defending another person during an assault is legal in every state under defense of others law.

The force you use must match the threat, just like self-defense. If the attacker poses a deadly threat, greater force is justified; if the threat is minor, lesser force applies. You must also reasonably believe the other person faced an immediate danger, and stop once the threat ends.

Some states require you to step into the shoes of the person you are defending, while others apply a standalone reasonable belief standard. Understanding your state's rule helps you act legally, similar to the framework for is it legal to defend yourself during a robbery.

Protecting someone else during an assault becomes illegal when:

• The other person did not actually face a real threat, since defense of others requires a reasonable belief of immediate danger.
• You use more force than the threat justified, such as deadly force against a minor assault.
• You continue attacking after the threat ends, since defense ends with the danger.
• You intervene on behalf of the initial aggressor, since defense of others protects only the person facing unlawful force.
• You fail to retreat when required in a duty-to-retreat state and could have safely removed the victim.
• You use a deadly weapon against a non-deadly threat, which is never reasonable.

See also: when can you legally use reasonable force for the proportionality standard that applies here.

Defending someone else during an assault is legal when:

• You reasonably believed the other person faced an immediate, unlawful threat of harm.
• The force used was proportionate to the threat, meaning only what was necessary.
• You did not use deadly force against a non-deadly threat, since deadly force requires a deadly danger.
• You stopped once the threat ended, rather than continuing.
• You followed any duty-to-retreat rules your state requires, including for the victim.

Most states allow reasonable force to defend family members, and many extend the right to defend any person facing an immediate threat, as explained in can you be arrested for self-defense.

If the defense of others is not legally justified, consequences can include:

• Misdemeanor assault charges: Apply when excessive but non-deadly force causes minor injury, with up to a year in jail.
• Felony assault charges: Apply when excessive force causes serious injury, carrying several years in prison.
• Homicide charges: Can apply if unjustified deadly force was used during the intervention.
• Civil lawsuits: The attacker can sue for injuries sustained during the intervention.
• Criminal record: A conviction affects employment, firearm rights, and other long-term consequences.

Even with good intentions, intervening with excessive force can convert you into the defendant.

Most defense-of-others cases arise when someone intervenes in a fight, domestic dispute, or street assault and the original attacker is injured.

Police respond and separate the parties, then evaluate whether the intervention was justified. Investigators consider whether the victim faced a real, immediate threat, whether the force was proportionate, and whether the threat had ended when force was used.

If the intervention meets the state's defense-of-others standard, no charges follow. If the force was excessive or the threat had ended, the intervener can face assault or even homicide charges, despite acting to help another person.

• Intervene only when the victim faces a real, immediate threat, since defense of others requires genuine danger.
• Use only proportionate force, matching the level of the attack.
• Stop as soon as the threat ends, since continuing turns defense into assault.
• Call police immediately, so the incident is documented and the victim receives help.
• Avoid using deadly force unless the attacker poses a deadly threat, since disproportionate force leads to charges.
• Be cautious in disputes where the aggressor is unclear, since backing the wrong party removes the defense.
• See also: is it legal to defend yourself during a robbery for robbery-specific rules.