<i>Herring v. United States</i>: The Continued Erosion of the Exclusionary Rule

At its inception, the exclusionary rule was relatively straightforward: The use at trial of evidence obtained from a search or seizure that violated a defendant's Fourth Amendment rights was itself a violation of the defendant's constitutional rights. But throughout the exclusionary rule's history, its source, scope, purpose, and applicability have all seen changes, ultimately limiting the situations in which evidence obtained through a Fourth Amendment violation would be suppressed. The key to the limitation of the exclusionary rule was the United States Supreme Court's eventual conclusion that the use at trial of illegally seized evidence does not always violate the Constitution. The court's decision in Herring v. United States is the most recent in a long line of cases in which the Court has limited the applicability of the exclusionary rule through the "good faith exception." By extending a preexisting exception to the exclusionary rule, Herring made the rule inapplicable when a police officer makes an arrest with a mistaken but reasonable belief that there is a valid warrant, despite the fact that the officer's mistaken belief was caused by another officer's negligence.