Not all mistakes are a defense to a criminal charge. For example, the fact that you’re unaware that punching someone in the face is a crime is not a defense. The affirmative defense mistake is defined in section 939.43 of the Wisconsin Statutes:
Again, a mistake about what criminal law is, is not, or prohibits, is not a defense. An error of fact or civil law is a defense if it results it negatives the existence of a state of mind essential for the crime. Importantly, crimes involving minors (including, among others, sexual assault) don’t qualify for the mistake defense if the mistake deals with the age of the minor.
Certain crimes require a state of mind in order to sustain a conviction. For example, the crime of operating a vehicle without owner’s consent requires that the defendant knew the victim did not consent to the taking of his vehicle. The mistake defense applies if it can be shown the defendant believed he had consent to operate the victim’s vehicle. In this case, what the defendant “knew” is the focus.
Crimes involving negligence, because they lack a “knowing” state of mind cannot use the mistake defense.
In State v. Lindvig, 205 Wis. 2d 100 (Ct. App. 1996), the Court of Appeals held that the defense of mistake wasn’t available to a defendant charged with negligent operation of a dangerous weapon. The reason for the unavailability was that criminal negligence, an element of the crime, does not require a mental state. Criminal negligence is an objective standard that requires “conduct which the actor should realize creates a substantial and unreasonable risk of death or great bodily harm to another.”
The same reasoning applies to crimes that rely on an element of recklessness.
If the mistake defense applies in your case you still have a battle. The defense is one that’s proven at trial. Hiring a skilled and experienced criminal defense attorney is crucial. Call our criminal defense firm at (414) 270-0202 if you’ve been accused of a crime and want an aggressive, intelligent criminal defense attorney on your side. We defend all criminal and drunk driving charges.