Exclusionary Rule Definition and Legal Meaning

On this page, you'll find the legal definition and meaning of Exclusionary Rule, written in plain English, along with examples of how it is used.

What is Exclusionary Rule?

n. the rule that evidence secured by illegal means and in bad faith cannot be introduced in a criminal trial. The technical term is that it is “excluded” upon a motion to suppress made by the lawyer for the accused. It is based on the constitutional requirement that ” no \[person\] can be deprived of life, liberty, or property, without due process of law” (Fifth Amendment to the Constitution, applied to the states by 14th Amendment). A technical error in a search warrant made in good faith will not cause exclusion of the evidence obtained under that warrant. In 1995 the U. S. Supreme Court ruled that evidence obtained with a warrant that had been cancelled could be admitted if the law enforcement officer believed it was still in force. However, evidence which was uncovered as a result of obtaining other evidence illegally will be excluded, under the “fruit of the poisonous tree doctrine.” Thus, if an illegal wire tap reveals the location of other evidence, both the transcript of the wire tap conversation and the evidence to which the listeners were directed will be excluded.

History and Meaning of Exclusionary Rule

The exclusionary rule is a legal concept that evidence obtained illegally cannot be used against an accused party in a criminal trial. The rule is based on the Fourth Amendment to the United States Constitution which prohibits unreasonable searches and seizures. The rule was first established in 1914 in the Supreme Court case of Weeks v. United States, where the Court held that evidence obtained by the government in violation of the Fourth Amendment must be excluded from trial.

Over the years, the exclusionary rule has been refined by several Supreme Court cases. In 1961, Mapp v. Ohio extended the rule to state courts, and in 1984, United States v. Leon created an exception to the rule for good-faith mistakes by law enforcement officers. In 1995, the Supreme Court decision in Arizona v. Evans made an exception to the rule for clerical errors.

Examples of Exclusionary Rule

  1. In a drug possession case, police officers illegally searched the defendant's car without a warrant and found a bag of cocaine. The defendant's lawyer filed a motion to suppress the evidence, citing the exclusionary rule. The court granted the motion and the evidence was not allowed to be used against the defendant.

  2. In a robbery trial, the prosecution attempted to use surveillance footage obtained without a warrant from a nearby store to identify the defendant. The defense lawyer filed a motion to suppress, arguing that the footage was obtained illegally. The court agreed and excluded the footage from trial.

  3. During a traffic stop, a police officer illegally searched a driver's trunk without consent or probable cause and found a bag of marijuana. The defendant's lawyer filed a motion to suppress the evidence, citing the exclusionary rule. The court granted the motion and the evidence was not allowed to be used against the defendant.

Legal Terms Similar to Exclusionary Rule

  1. Fruit of the Poisonous Tree Doctrine - this legal concept states that evidence obtained as a result of an illegal search or seizure, or from other illegally obtained evidence, is also inadmissible.
  2. Good-Faith Exception - this legal doctrine allows evidence to be admitted if the police officers acted in good faith, even if their conduct was technically in violation of the defendant's Fourth Amendment rights.
  3. Inevitable Discovery Doctrine - this legal concept allows evidence obtained illegally to be admissible if it would have inevitably been discovered through legal means.