[brief] In Mulvihill, our Supreme Court held that the trial court erroneously failed to instruct the jury on self-defense where the defendant got into a physical altercation with a uniformed police officer.  57 N.J. at 157-59.  The defendant and the police officer gave conflicting accounts of the events that transpired after the officer stopped the defendant for a suspected ordinance violation.  Recounting the facts in the light most favorable to the defendant, the Court noted that the defendant testified that the officer grabbed him and told him that he “should” arrest him, and a struggle ensued when he tried to free himself.  After the officer struck the defendant on the head with his gun and pointed it at him, the defendant grabbed the officer’s hand to point the gun away from himself, a shot went off harmlessly, and the defendant punched the officer, before being arrested and charged with assault and battery on a police officer.  Id. at 154-155.  The Supreme Court identified two separate bases for its conclusion that the trial court erred in failing to instruct the jury on self-defense.  First, the Court held that there was a factual dispute for the jury to resolve regarding whether the defendant was arrested prior to punching the officer.  Had the jury found that the officer’s assertion that he “should” arrest the defendant did not constitute an arrest, “the fracas between the two men [would take] on the character of a combat between two private individuals,” and the defendant would be entitled to have the jury determine whether he hit the police officer in self-defense.  *Id.* at 158-59.  The Court found that this was the “more crucial basis for accepting self-defense as a legitimate contention in this case,” although it was not raised before the trial court.  *Id.* at 157.  Second, the Court held that the trial court should have instructed the jury on self-defense even if the jury had found that the police officer “informed [defendant] expressly, or by his course of conduct that he was under arrest. ”  *Id.* at 158.  If the defendant was under arrest when he hit the officer, the question before the jury would then be whether the officer employed excessive force in attempting to overcome the defendant’s resistance, and whether the defendant reasonably acted in self-defense to repel the excessive force “in light of all the circumstances apparent to him at the moment. ”  *Id.* at 157.  The Court held that the law of this state permits “reasonable resistance” to an officer’s use of excessive force.  *Ibid.*  Therefore, the Court held that on retrial, the jury must be instructed to “consider the matter of self-defense” in accordance with the appropriate theory based on its factual determination regarding when the arrest occurred.  *Id.* at 159.  Were the jury to find that the defendant was not under arrest at the time of the altercation, it should apply the same self-defense principles to the altercation between the defendant and the officer as ordinarily apply to combat between private individuals.  Were the jury to find that the altercation took place after the defendant was arrested, it should determine whether the officer employed excessive force, and whether the defendant reasonably acted in self-defense to repel the excessive force.  See ibid.  Similarly, in State v. [...], our Supreme Court reversed the defendant’s conviction for assault on a police officer due to the trial court’s failure to properly instruct the jury on the defendant’s right to intervene in defense of his niece where there was sufficient evidence that the defendant reasonably believed that the officer was beating his niece in response to her verbal taunts.