Fourth Amendment To The United States Constitution - Exclusionary Rule

Exclusionary Rule

One way courts enforce the Fourth Amendment is through the use of the exclusionary rule. The rule provides that evidence obtained through a violation of the Fourth Amendment is generally not admissible by the prosecution during the defendant's criminal trial.

The Court adopted the exclusionary rule in Weeks v. United States, 232 U.S. 383 (1914), prior to which all evidence, no matter how seized, could be admitted in court. Additionally, in Silverthorne Lumber Co. v. United States, 251 U.S. 385 (1920) and Nardone v. United States, 308 U.S. 338 (1939), the Court ruled that tips resulting from illegally obtained evidence are also inadmissible in trials as "fruit of the poisonous tree". The rule serves primarily to deter police officers from willfully violating a suspect's Fourth Amendment rights. The rationale behind the exclusionary rule is that if the police know evidence obtained in violation of the Fourth Amendment cannot be used to convict someone of a crime, they will not violate it. In Wolf v. Colorado, 338 U.S. 25 (1949), the Court rejected incorporation of the exclusionary rule by way of the Fourteenth Amendment. Later, in Mapp v. Ohio, 367 U.S. 643 (1961), the Court explicitly overruled Wolf and made the Fourth Amendment (including the exclusionary rule) applicable in state proceedings as an essential part of criminal procedure.