Exclusionary Rule Legal Meaning and Definition

Here is a simplified definition of the legal term Exclusionary Rule.

Exclusionary Rule (noun): A legal principle that prohibits the use of evidence in a criminal trial if it was obtained through unlawful means. This rule is derived from the constitutional guarantee that a person cannot be deprived of life, liberty, or property without due process of law, as described in the Fifth and Fourteenth Amendments. Exceptions to this rule may occur if law enforcement officials believed their actions were lawful, say if they acted on a warrant they thought was valid but had been cancelled. However, the "fruit of the poisonous tree doctrine" states any evidence found as a result of initially unlawful behavior must also be excluded.