Exclusionary Rule

Doctrine that says evidence obtained in violation of a criminal defendant's constitutional or statutory rights is not admissible at trial.

Additional Sources

Answers.com

The name commonly given to the principle that evidence obtained by the government in violation of a defendant's constitutional right may not be used against him. A defendant may prevent the prosecution from using evidence against her by making a “motion to suppress” before trial asking the judge to rule that the evidence is inadmissible. Physical evidence, confessions, or line?up identifications are all subject to exclusion if obtained in violation of a defendant's constitutional right. The term exclusionary rule usually refers, however, to suppression of physical evidence that has been seized by the police in violation of a defendant's Fourth Amendment right not to be subjected to an unreasonable search or seizure. (See Search Warrant Rules, Exceptions to.) The Burger and Rehnquist Courts have substantially curtailed the degree to which the exclusionary principle actually operates as a “rule.” This curtailment reflects a fundamental redefinition of the character and purpose of the rule.

Encyclopedia Britannica

In U.S. law, the principle that evidence seized by police in violation of the Fourth Amendment to the U.S. Constitution may not be used against a criminal defendant at trial.

The Fourth Amendment guarantees freedom from unreasonable searches and seizures—that is, those made without a warrant signed by a judge. The U.S. Supreme Court held in Wolf v. Colorado (1949) that “security of one’s privacy against arbitrary intrusion by the police—which is at the core of the Fourth Amendment—is basic to a free society.” However, that decision did not extend to state courts. During the next decade, approximately half of the states adopted the rule. Later the Supreme Court held in Mapp v. Ohio (1961) that the rule had to be applied universally to all criminal proceedings.

The broad provisions of the exclusionary rule came under legal attack, and in U.S. v. Leon (1984) the Supreme Court held that evidence obtained “in good faith” with a search warrant later ruled invalid was admissible. A central argument was the unacceptable social cost of excluding such evidence, a reason subsequently given for creating further exceptions to the rule.

FindLaw

A rule of evidence that excludes or suppresses evidence obtained in violation of a defendant's constitutional rights.

Law.com Dictionary

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.

Legal-Dictionary.org

A constitutional rule that says otherwise admissible evidence may not be used in a criminal trial if it was the product of illegal police activity.

The Free (Legal) Dictionary

The exclusionary rule is designed to exclude evidence obtained in violation of a criminal defendant's Fourth Amendment rights. The Fourth Amendment protects against unreasonable searches and seizures by law enforcement personnel. If the search of a criminal suspect is unreasonable, the evidence obtained in the search will be excluded from trial.

The exclusionary rule is a court-made rule. This means that it was created not in statutes passed by legislative bodies but rather by the U.S. Supreme Court. The exclusionary rule applies in federal courts by virtue of the Fourth Amendment. The Court has ruled that it applies in state courts although the due process clause of the Fourteenth Amendment.(The Bill of Rights—the first ten amendments— applies to actions by the federal government. The Fourteenth Amendment, the Court has held, makes most of the protections in the Bill of Rights applicable to actions by the states.)

Wikipedia

The exclusionary rule is a legal principle in the United States, under constitutional law, which holds that evidence collected or analyzed in violation of the defendant's constitutional rights is sometimes inadmissible for a criminal prosecution in a court of law. This may be considered an example of a prophylactic rule formulated by the judiciary in order to protect a constitutional right. However, in some circumstances at least, the exclusionary rule may also be considered to follow directly from the constitutional language, such as the Fifth Amendment's command that no person "shall be compelled in any criminal case to be a witness against himself" and that no person "shall be deprived of life, liberty or property without due process of law."

The exclusionary rule is designed to provide a remedy and disincentive, short of criminal prosecution, in response to prosecutors and police who illegally gather evidence in violation of the Fourth and Fifth Amendments in the Bill of Rights, by conducting unreasonable searches and seizure or compelled self-incrimination. The exclusionary rule also applies to violations of the Sixth Amendment, which guarantees the right to counsel.

This rule is occasionally referred to as a legal technicality because it allows defendants a defense that does not address whether the crime was actually committed. In this respect, it is similar to the explicit rule in the Fifth Amendment protecting people from double jeopardy.

The exclusionary rule judges the admissibility of evidence based on deontological ethics; that is, it is concerned with how evidence is acquired, rather than what the evidence proves. For this reason, in strict cases, when an illegal action is used by police/prosecution to gain any incriminating result, all evidence whose recovery stemmed from the illegal action—this evidence is known as "fruit of the poisonous tree"—can be thrown out from a jury (or be grounds for a mistrial if too much information has been irrevocably revealed).

The exclusionary rule applies to all persons within the United States regardless of whether they are citizens, immigrants (legal or illegal), or visitors.