MBE Fast Fact: Mistake of Law

One of the most difficult areas of Criminal Law is the defenses. It's easy to confuse mistake of fact with factual impossibility, and mistake of law with legal impossibility. One way to avoid this confusion is understand that factual impossibility and legal impossibility will be raised as a defense only if defendant fails to complete the crime. In contrast, mistake of fact and mistake of law will be raised as a defense only after defendant has completed the crime.

There is a saying that ignorance of the law is no excuse. For the most part, that is correct, but there are exceptions. (It seems as though there always are.) Specifically, in regards to the defense of mistake of law (where the defendant claims he believed his actions were legal though they were in fact illegal), it's important to note that this is generally not a defense even if the belief was reasonable and based on the advice of an attorney.

There is an important exception here, however. Mistake of law will be valid if the statute proscribing defendant's conduct was not published or made reasonably available prior to the conduct for which defendant has been charged, or if defendant reasonably relied on a statute or judicial decision that indicated his conduct was legal. The key here is certainly the word "reasonable." This is an objective test, so that it won't be enough for defendant to claim he subjectively relied on a statute resulting in his mistake; it must be true that a reasonable person would have made the same mistake.