When a defendant introduces evidence at trial showing that the State has failed to prove some element of the crime, the strategy is sometimes described as a failure of proof or “negating” defense. Mistake of fact is one such negating defense. Mistake of fact offers a defense if it negates a mental state required to establish an element of the crime. State v. Breathette, ___ N.C. App. ___, 690 S.E.2d 1, 4 (2010). For example, mistake of fact is a defense to larceny if the defendant establishes that he or she took the property under a reasonable but mistaken belief that he or she was the lawful possessor of the property. There are numerous cases on point. One is State v. Lamson, 75 N.C. App. 132, 135-36 (1985), a burglary case in which the court held that the trial court erred by not giving an instruction on mistake of fact when there was evidence that the defendant thought he was entering a house where his friend was visiting. Another is State v. Walker, 35 N.C. App. 182, 186-87 (1978), in which the court held that the trial court erred by not giving an instruction on mistake of fact when the defendant and his son mistakenly abducted a child believed to be the defendant’s granddaughter.
There are, however, limitations on this defense. Most significantly, when the elements of the crime do not require the defendant to know the fact that he or she was mistaken about, mistake of fact is no defense. For example, because a defendant need not know the victim’s age for statutory rape, mistake as to the victim’s age is no defense to this crime. State v. Browning, 177 N.C. App. 487, 492-94 (2006). The same is true for indecent liberties with a child. Breathette, ___ N.C. App. ___, 690 S.E.2d at 4-6. However, mistake of fact can be a defense for some statutory sexual assault charges. For example, if the defendant is charged with aiding and abetting statutory rape, mistake of fact is a defense. This is so because aiding and abetting requires that the defendant knowingly aid the perpetrator in committing the offense. State v. Bowman, 188 N.C. App. 635, 647-50 (2008) (in an aiding and abetting statutory rape case, the trial court erred by failing to instruct as to mistake of fact; North Carolina does not recognize vicarious strict liability). Also, at least one case has held that if the defendant argues that a touching was accidental, mistake of fact may be a defense to a sexual assault on a child. State v. Connell, 127 N.C. App. 685, 690-91 (1997) (in an indecent liberties case in which the State presented only circumstantial evidence that the defendant was awake and intended to touch the child and the defendant’s evidence indicated that he thought he was touching the child’s mother, the trial court should have instructed the jury as to the mistake of fact).
Mistake of fact, which can be a valuable negating defense, should not be confused with mistake of the law. Mistake or ignorance of law, as a general rule, is no excuse. State v. Howard, 158 N.C. App. 226, 233 (2003); State v. Rogers, 68 N.C. App. 358, 385 (1984). Thus, a defendant charged with rape of a 15-year-old will not prevail on the defense that he didn’t know that having sex with a 15-year-old was a crime.