Legal impossibility

Defense stating an act cannot be a crime if completed

Legal impossibility is a traditional common law defense to a charge of an attempted crime. Legal impossibility arises when the act, if completed, would not be a crime. A person believes she is committing a crime, but the act is, in fact, lawful. For example, a person may believe she is receiving stolen goods, but the goods are in fact not stolen.

This keyword could refer to multiple things. Here are some suggestions: