Mistake of Fact and Mistake of Law Defenses
Most crimes require intent. If you genuinely misunderstood the facts — and a reasonable person in your position would have made the same mistake — the prosecution may not be able to prove you had the mental state the crime requires. Mistake of law is a harder argument, but it has narrow applications.
17 Google reviews
Mike is a really great attorney who has had big wins for his clients at every level in Nevada.
— Charles JacksonTwo defenses — very different success rates
Mistake of fact
"I misunderstood the situation"
You genuinely believed facts that, if true, would have made your conduct legal. The mistake must be honest and reasonable. If a reasonable person in your position would have made the same error, the prosecution may not be able to prove intent.
Viability: Strong in the right case
Mistake of law
"I didn't know it was illegal"
You did not know your conduct violated the law. Courts almost always reject this — ignorance of the law is not an excuse. The only recognized exceptions involve reliance on official government guidance that turned out to be wrong, or laws that were genuinely inaccessible.
Viability: Rarely succeeds
When mistake of fact works
Three conditions must be met. All three are required.
The mistake was reasonable
Your belief must be one that a reasonable person in the same circumstances could have held. Not a wild guess. Not wishful thinking. A genuine, understandable misreading of the situation based on the information available to you at the time.
The crime requires intent
The defense applies to specific intent crimes — offenses where the prosecution must prove you intended a particular result. Theft (intent to permanently deprive), fraud (intent to deceive), burglary (intent to commit a crime inside). If the crime is strict liability, mistake of fact is irrelevant.
The mistake negates the required mental state
Your misunderstanding must directly eliminate the intent the prosecution needs to prove. If you took property believing it was yours, you lacked the intent to steal. If you entered a building believing you had permission, you lacked the intent to trespass. The mistake must connect to the element of intent, not just the surrounding circumstances.
How it plays out — real examples
Theft — mistake of fact
You take a bag from the airport carousel that looks identical to yours. You open it at your hotel and discover it belongs to someone else. You had no intent to steal — you genuinely believed it was your property. The mistake negates the intent element of theft.
Felon in possession — mistake of fact
In People v. Bray, a man was charged with being a felon in possession of a firearm. He genuinely and reasonably believed his prior conviction was a misdemeanor, not a felony. The court held that his mistaken belief about his own record negated the required knowledge that he was a prohibited person.
Trespass — mistake of fact
You enter property believing you have permission — a friend told you the owner said it was fine. If your belief was reasonable, the intent to trespass is missing. The prosecution would need to show you knew or should have known you were not welcome.
Tax fraud — mistake of law (rare exception)
You claimed a deduction based on published IRS guidance that later turned out to be incorrect. Because you relied on an official government source — not a private accountant — the mistake of law defense may apply. This is one of the very few scenarios where ignorance of the law can be an excuse.
Where these defenses do not work
Strict liability crimes
If the law does not require intent, your mental state does not matter. Speeding, selling alcohol to a minor, certain environmental violations — the act itself is the crime regardless of what you believed. Neither mistake of fact nor mistake of law applies.
Unreasonable mistakes
A belief that no reasonable person would share does not qualify. If you took someone else's clearly labeled, monogrammed luggage and claimed you thought it was yours, the jury is unlikely to find that reasonable. The standard is objective — what would a reasonable person in your position have believed?
Willful ignorance
Deliberately avoiding knowledge does not create a valid mistake. If you suspected a package contained drugs but chose not to open it so you could claim ignorance, courts treat that as equivalent to actual knowledge. You cannot manufacture a defense by choosing not to look.
General ignorance of the law
Outside the narrow exceptions (official government advice, genuinely inaccessible law), not knowing something was illegal is not a defense. Courts expect people to know the law — even laws they have never heard of. This is a hard rule, but it is the rule.
Mistake Defenses — Frequently Asked Questions
Common questions about mistake of fact and mistake of law defenses in Nevada.
Frequently Asked Questions
Clear answers to common record sealing questions.
Think a misunderstanding led to your charges?
Whether a mistake defense applies depends on the specific facts and the specific charge. Call for a free consultation — we will review the evidence and tell you whether this defense is viable in your case.
Related
Tap any topic for the full guide.