When The Exclusionary Rule Does Not Apply

Fundamentals of Procedural Law by Adam J. McKee

The Exclusionary Rule, which we have just discussed in detail, plays a fundamental role in ensuring that our rights are protected from unwarranted government intrusion. However, as with many legal principles, it is not absolute and comes with certain exceptions. In this section, we will delve into these exceptions to gain a more nuanced understanding of how the rule applies in the real world.

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The Good Faith Exception

One key exception to the Exclusionary Rule is the Good Faith Exception. The term “good faith” refers to the honest and sincere intentions of the person or entity involved. In the context of the Exclusionary Rule, the Good Faith Exception essentially states that if law enforcement officers have a reasonable belief that their actions are lawful, the evidence they obtain, even if it later turns out that their actions were unlawful, may not be excluded from the trial.

In the landmark Supreme Court case, United States v. Leon (1984), the Good Faith Exception was firmly established. The case involved law enforcement officers who conducted a search based on a warrant that was later found to be defective. The Court ruled that because the officers acted in good faith, believing the warrant to be valid, the evidence obtained should not be excluded. The ruling held that the purpose of the Exclusionary Rule is to deter unlawful police conduct. If the police conduct a search believing it to be legal, then the rule has no purpose (United States v. Leon, 1984).

The Independent Source Doctrine

The Independent Source Doctrine is another significant exception to the Exclusionary Rule. It stipulates that evidence initially discovered during, or as a consequence of, an unlawful search may be admissible if it is later obtained independently through activities untainted by the initial illegality.

This doctrine was reaffirmed in Murray v. United States (1988). In this case, federal agents illegally entered a warehouse and saw burlap-wrapped bales that they suspected were drugs. They left without disturbing anything and later obtained a search warrant without mentioning the illegal entry. Upon returning with the warrant, they seized the bales, which were indeed drugs. The Court held that because the warrant was not based on the illegal entry and the drugs would have been discovered anyway, the Independent Source Doctrine could apply, and the drugs could potentially be admissible as evidence (Murray v. United States, 1988). This case reinforces the principle that while our legal system discourages unlawful conduct by authorities, it also recognizes the necessity of ensuring that guilt does not escape conviction due to technicalities.

The Inevitable Discovery Doctrine

Our next stop on this exploration of exceptions to the Exclusionary Rule is the Inevitable Discovery Doctrine. This doctrine allows for evidence that was obtained illegally to be admitted in court if the prosecution can show that the evidence would have inevitably been discovered by legal means. This is, in essence, a sort of “what if” scenario – if the police would have found the evidence anyway, through legal means, then the court may decide to allow it.

The Supreme Court upheld this doctrine in the case of Nix v. Williams (1984). In this case, a suspect was in custody and had requested an attorney, but police continued to talk to him, eventually leading them to the body of a missing child. The Supreme Court ruled that although the evidence was obtained illegally, it would have inevitably been discovered because a search party was already closing in on the location of the body (Nix v. Williams, 1984).

The Attenuation Doctrine

The last exception we’ll cover is the Attenuation Doctrine. This principle applies when the connection between the illegal action and the evidence discovered is so distant or has been interrupted by some other event that the taint from the initial illegal action is no longer present.

One of the key cases for this doctrine is Brown v. Illinois (1975). In this case, the police arrested Brown without probable cause, and during subsequent questioning, Brown made incriminating statements. The Court held that those statements could not be used against Brown because the arrest was illegal and the statements were not sufficiently an “act of free will” to break the connection with the illegal arrest (Brown v. Illinois, 1975).


As we have seen, the Exclusionary Rule is a fundamental safeguard in our justice system, but it does have its limits. These exceptions – the Good Faith Exception, the Independent Source Doctrine, the Inevitable Discovery Doctrine, and the Attenuation Doctrine – highlight the balance the legal system strives to maintain between protecting individual rights and ensuring that justice is served.


The Exclusionary Rule, though a fundamental safeguard in the U.S. justice system, is not absolute. There are several exceptions that courts have recognized to strike a balance between protecting individual rights and ensuring justice is served. The Good Faith Exception, first validated in United States v. Leon (1984), allows evidence obtained in violation of the Fourth Amendment to be admitted if officers acted with a reasonable belief that their conduct was legal. The Independent Source Doctrine, reaffirmed in Murray v. United States (1988), permits evidence to be admitted if it is obtained from a source separate from the initial, unlawful one.

The Inevitable Discovery Doctrine, upheld in Nix v. Williams (1984), allows the admission of illegally obtained evidence if it would have been discovered eventually through legal means. Lastly, the Attenuation Doctrine, established in Brown v. Illinois (1975), admits evidence if the connection between the illegal action and the evidence discovered is distant or has been disrupted by some other event. Understanding these exceptions is essential for a full comprehension of the Exclusionary Rule and its role in the U.S. legal system.


Modification History

File Created:  08/08/2018

Last Modified:  07/24/2023

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