John Hughes (defendant) and Rodney Johnson had a problematic past. On the day of the events in question, Mary Hodge was driving Joan Goodwin and Hughes to Mary’s house. Rodney passed by in his truck and turned around to follow Mary’s car. Mary pulled over, and Joan and Hughes exited the car to talk to Rodney. Rodney cursed at Hughes. Joan testified that Rodney grabbed her and threatened her with a gun. At that moment, Hughes shot Rodney, killing him. Hughes was indicted for murder. According to Texas Penal Code (the Code) § 9.32, a defendant is justified in using deadly force if a reasonable person in the situation would not have retreated and the defendant reasonably believed that the deadly force was immediately necessary for self-defense. Section 9.33 of the Code addresses the defense of a third person, stating that such action is justified if the defendant would be justified under § 9.32 of the Code and reasonably believes that intervention is immediately necessary to protect the third person. The trial court instructed the jury that a defendant is justified in using deadly force when the defendant believes such force is necessary to protect a third person and a reasonable person in the situation would not have retreated. The jury convicted Hughes of voluntary manslaughter. The court of appeals reversed, holding that the trial court erred in instructing the jury that Hughes was only entitled to use force in Joan’s defense if a reasonable person in Hughes’s situation would not have retreated. The state petitioned for discretionary review.