Issues
The issued presented before the U. S. Supreme Court was whether a 'good faith exception' to the Fourth Amendment's exclusionary rule should be recognized.
Holding
The U.S. Supreme Court determined that there should be an exception to the exclusionary rule of the Fourth Amendment. They held that when a police officer acts in a reasonable manner relying on a search warrant that was issued by a neutral magistrate, but ultimately found to be invalid, the evidence collected should not be barred from trial.
Rationale
The U.S. Supreme Court examined the Fourth Amendment's origin and purpose when determining whether or not to impose exclusionary rule in this particular set of facts. They weighed the benefits and the costs of preventing the District Attorney's from using the inherently trustworthy and tangible evidence in their case in chief.
After weighing those factors they determined that the exclusionary rule should be used where a Fourth Amendment violation has been substantial and deliberate, but that a balancing approach should be used in determining whether the rule should be applied in a variety of contexts, including criminal trials. This suggests that the rule should be modified to permit the introduction of evidence obtained by officers reasonably relying on a warrant issued by a detached and neutral magistrate.
They U.S. Supreme Court's rationale for the Fourth Amendment is to deter police misconduct. This was an essential part of determining whether or not the 'good faith exception' would apply in this case. Here it was the magistrate's error, not the police officer's, that caused the search warrant to become invalid. The court determined that the Fourth Amendment cannot be used to deter objectively reasonable law enforcement activity. It was their determination that an officer cannot be expected to question the magistrate's probable cause determination or his judgment; the form of the warrant is technically sufficient. Once the warrant is issued, the police officers must then comply with the laws and should not be penalized for a magistrate's error in the issuing of the warrant.
Lesson Summary
In conclusion, United States v. Leon was a landmark legal case which established an exception to the exclusionary rule of the Fourth Amendment: that evidence obtained from invalid search warrants due to a judicial, or magistrate-made, error was still admissible, provided one could demonstrate that the magistrate issuing the search warrant was neutral and detached, that there was substantial basis for determining the existence of probable cause, and that there was no police misconduct.
