## Facts

- In Manhattan, Young saw two older men using force against a younger man who was calling for help.
- Young, a stranger to all involved, believed the younger man was being unlawfully beaten and intervened to protect him.
- The two older men were plainclothes police officers attempting to arrest the younger man, who was resisting.
- Young, unaware they were officers, fought with one officer, who fell and suffered a broken kneecap.
- Young was charged with and convicted of third-degree assault.

## Issues

1. Whether a defendant’s intentional use of force amounting to assault is excused as a matter of law when motivated by a mistaken (even reasonable) belief that he is defending another from an unlawful assault.
2. Whether mistake-of-fact-based justification negates the intent element of assault or instead presents a factual defense for the jury.

## Decision

- The New York Court of Appeals reversed the Appellate Division’s order vacating the conviction.
- The court held that Young’s alleged justification based on mistake of fact did not eliminate assault liability as a matter of law.
- The court concluded that whether Young’s belief and conduct were legally justified was a question for the jury under appropriate instructions, not a basis to dismiss or vacate outright.

## Legal Principles

- Assault liability turns on the defendant’s intent to inflict physical injury or to cause immediate apprehension of such injury, not on the perceived moral quality of the defendant’s motive.
- A mistaken belief that force is justified (including a belief that one is defending another) does not automatically negate the mens rea for assault when the defendant intentionally applies force.
- Evidence supporting justification grounded in mistake of fact may warrant submission of a defense to the jury, but it does not bar prosecution as a matter of law.
- Appellate courts should not remove justification questions from the factfinder where the reasonableness and legal effect of the defendant’s belief depend on factual determinations.

## Conclusion

The court held that an intentional assault is not excused as a matter of law merely because the defendant acted under a mistaken belief that he was defending another; the claimed justification is a factual matter for the jury to decide.


People v. Young, 11 N.Y.2d 274, 183 N.E.2d 319 (N.Y. 1962)