Self defense is an affirmative defense to a criminal charge -- most often assault and battery or a varient thereof. A Defendant may assert that he or she acted in self defense, but he does not have to prove that he acted in self defense; rather, the Prosecution must prove that the Defendant did not act in self defense. Below are the jury instructions for using force in self defense:
M Crim JI 7.20 Burden of Proof-Self—Defense
The defendant does not have to prove that [he / she] acted in self-defense. Instead, the prosecutor must prove beyond a reasonable doubt that the defendant did not act in selfdefense.
M Crim JI 7.22 Use of Nondeadly Force in Self-Defense or Defense of Others
(1) The defendant claims that [he / she] acted in lawful [self-defense / defense of ___________]. A person has the right to use force to defend [himself / herself / another person] under certain circumstances. If a person acts in lawful [self-defense / defense of others], [his / her] actions are justified and [he / she] is not guilty of [state crime].
(2) You should consider all the evidence and use the following rules to decide whether the defendant acted in lawful [self-defense / defense of ___________]. Remember to judge the defendant’s conduct according to how the circumstances appeared to [him / her] at the time [he / she] acted.
(3) First, at the time [he / she] acted, the defendant must not have been engaged in the commission of a crime.
(4) Second, when [he / she] acted, the defendant must have honestly and reasonably believed that [he / she] had to use force to protect [himself / herself / ___________] from the imminent unlawful use of force by another. If [his / her] belief was honest and reasonable, [he / she] could act at once to defend [himself / herself / ___________], even if it turns out later that [he / she] was wrong about how much danger [he / she / ___________] was in.
(5) Third, a person is only justified in using the degree of force that seems necessary at the time to protect [himself / herself / the other person] from danger. The defendant must have used the kind of force that was appropriate to the attack made and the circumstances as [he / she] saw them. When you decide whether the force used was what seemed necessary, you should consider whether the defendant knew about any other ways of protecting [himself / herself / ___________], but you may also consider how the excitement of the moment affected the choice the defendant made.
(6) Fourth, the right to defend [oneself / another person] only lasts as long as it seems necessary for the purpose of protection.
(7) Fifth, the person claiming self-defense must not have acted wrongfully and brought on the assault. [However, if the defendant only used words, that does not prevent (him / her) from claiming self-defense if (he / she) was attacked.]