Also known as: mistake-of-fact defense · mistake of fact · mistakes of fact defense · ignorance of fact · factual mistake
Written by attorneys · grounded in primary & secondary sources — see below
2 senses
A defense available when a defendant's honest but erroneous belief about existing facts prevents the formation of the culpable mental state required for the offense. The defense succeeds only when the mistake directly negates purpose, knowledge, belief, recklessness, or negligence as to a material element. It does not excuse reckless disregard of readily available information that would have corrected the error.
A ground for reforming an unambiguous donative document when clear and convincing evidence establishes that a mistake of fact or law affected specific terms and reveals the donor's true intention. Reformation corrects errors in expression or inducement so the document conforms to what the donor actually intended. The remedy applies to wills and will substitutes alike.
Each sense below has its own examples, sources, and questions.
A defense available when a defendant's honest but erroneous belief about existing facts prevents the formation of the culpable mental state required for the offense. The defense succeeds only when the mistake directly negates purpose, knowledge, belief, recklessness, or negligence as to a material element. It does not excuse reckless disregard of readily available information that would have corrected the error.
Select any source to read its text and confirm it supports the definition.
Officer Ramirez lawfully attempts to arrest Miguel Mendoza after a valid warrant issues. Mendoza, unaware of the warrant because of a clerical error in the database he checked, believes the officer is acting without authority and resists with force. Because Mendoza's mistake concerns the factual existence of the warrant rather than a legal privilege, the defense does not shield him from battery liability.
Marcus Mitchell engages in sexual intercourse with a woman who states she is eighteen. He honestly believes the statement and has reasonable grounds for doing so. The woman is actually sixteen. Because the mistake of fact negates the mental state required for statutory rape, Mitchell avoids conviction under the defense.
In criminal law the defense succeeds whenever the mistake negates the required mental state, even if the belief is unreasonable, provided the defendant actually held the belief. Recklessness or negligence in forming the belief may still support liability under a different mental-state element. Reformation in donative documents requires clear and convincing proof of the mistake and the donor's true intention regardless of reasonableness.
Supporting sources
Under the Model Penal Code approach adopted in many jurisdictions the defense reduces the grade of the offense to the lesser crime the defendant would have committed had the facts been as believed. The prosecution must still prove the elements of the lesser offense beyond a reasonable doubt.
A ground for reforming an unambiguous donative document when clear and convincing evidence establishes that a mistake of fact or law affected specific terms and reveals the donor's true intention. Reformation corrects errors in expression or inducement so the document conforms to what the donor actually intended. The remedy applies to wills and will substitutes alike.
Select any source to read its text and confirm it supports the definition.
Dennis executes a will leaving his donor-advised account at Helping Hands Fund to Elm Council. He maintains two accounts under different emails but refers to both collectively in conversations. After his death, clear and convincing evidence shows he intended both accounts to pass to the charity. The court reforms the will to include the omitted account.
Jessica creates a trust directing low-basis assets to one charity and her retirement account to another, producing unexpectedly high estate taxes. Clear and convincing evidence establishes she would have reversed the allocation had she known the tax consequences. The court reforms the trust terms to achieve her probable tax-saving intention.
In the trusts-and-estates context a mistake of law as to the legal effect of terms is treated the same as a mistake of fact and supports reformation when clear and convincing evidence shows both the error and the donor's actual intention. In criminal law a pure mistake of law rarely excuses liability unless the statute itself makes knowledge of the law an element.
Supporting sources
No. Reformation is available even when the document is unambiguous if clear and convincing evidence establishes that a mistake of fact or law affected specific terms and reveals the donor's true intention.
Supporting sources
…out of a second marriage when the first marriage had not in fact been terminated. ( Id. at pp. 801, 804-805.) However, the mistake of fact defense would not have been applicable if the first marriage had in fact been terminated. In this situation there is no mistake of fact; rather, the facts as they actually exist preclude a…
…that to constitute a crime there must be both a wrongful act and a guilty mind. Where a defendant has an honest and reasonable mistake of fact
…Creighton, supra . Our qualified immunity doctrine applies regardless of whether the officer's error is a mistake of law, a
…similar objections which doubtless were voiced with equal intensity to the long-accepted defenses of justification, accident,
…and the Utah Code generally. Holm bases this argument on subsection three of the bigamy statute, which essentially creates a mistake-of-fact defense
Malcolm McKinley, a federal agent, executes a search warrant he believes is facially valid. The warrant in fact fails to describe the items to be seized. Because the mistake concerns a factual defect in the warrant rather than a legal interpretation, the defense does not protect him from a Fourth Amendment violation claim.
An officer obtains a warrant that an informant describes as authorizing a search for weapons. The warrant actually authorizes a search for documents. The officer executes the warrant in good-faith reliance on the informant's description. Because the mistake of fact concerns the warrant's contents, qualified immunity may still attach.
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