U.S. v. Leon: Supreme Court Case, Arguments, Impact

The "Good Faith" Exception to the Fourth Amendment

A gloved hand writing on an evidence bag.

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In U.S. v. Leon (1984), the Supreme Court analyzed whether there should be a "good faith" exception to the Fourth Amendment exclusionary rule. The Supreme Court found that evidence should not be suppressed if an officer acts in "good faith" when carrying out a warrant that is later determined to be invalid.

Fast Facts: United States v. Leon

  • Case Argued: January 17, 1984
  • Decision Issued: July 5, 1984
  • Petitioner: United States
  • Respondent: Alberto Leon
  • Key Questions:  Is there a "good faith" exception to the exclusionary rule that requires evidence illegally seized must be excluded from criminal trials?
  • Majority Decision: Justices Burger, White, Blackmon, Rehnquist, and O’Connor
  • Dissenting: Justices Brennan, Marshall, Powell, and Stevens
  • Ruling: As the exclusionary rule was deemed a remedy rather than a right, the justices held that evidence seized on the basis of a mistakenly issued search warrant could be introduced at trial.

Facts of the Case

In 1981, officers from the Burbank Police Department began surveilling the residence of Alberto Leon. Leon had been arrested a year prior for drug charges. An anonymous informant told the police that Leon kept a large amount of methaqualone in his Burbank home. Police observed suspicious interactions at Leon's residence and other residences they were surveilling. A narcotics officer recorded the observations in an affidavit and applied for a search warrant. A State Superior Court Judge issued a search warrant and officers uncovered drugs at Leon's residence. Leon was arrested. A Grand Jury indicted him and several other respondents for conspiracy to possess and distribute cocaine, as well as other substantive counts.

At District Court, attorneys representing Leon and the other respondents filed a motion to suppress the evidence. The District Court decided that there was not sufficient probable cause to issue a warrant and the suppressed the evidence at Leon's trial. The Ninth Circuit Court of Appeals affirmed the decision. The Court of Appeals noted that they would not entertain "good faith" exceptions to the exclusionary rule of the Fourth Amendment.

The Supreme Court granted certiorari to consider the legality of admitting evidence obtained through a "facially valid" search warrant.

Constitutional Issue(s)

Can the exclusionary rule have a "good faith" exception? Should evidence be excluded if an officer believed he was carrying out a valid search warrant at the time of a search?


Attorneys representing Leon argued that evidence seized through an improper search warrant should not be allowed in court. The officers violated Leon's Fourth Amendment protection against unlawful search and seizures when they used a faulty warrant to enter his home. The attorneys argued that the Court should not make exceptions for search warrants issued without probable cause.

Attorneys representing the government argued that officers did their due diligence when they obtained a search warrant from a neutral judge. They acted in good faith when using that warrant to search Leon's home. Officers, and the evidence they seize, should not be affected by judicial error, according to the attorneys.

Majority Opinion

Justice White delivered the 6-3 decision. The majority ruled that officers had acted in good faith when searching Leon's home with a warrant that they believed to be valid.

The majority first reflected on the intent and usage of the exclusionary rule. The rule prevents illegally seized evidence from being used in court. It was originally intended to deter officers from intentionally violating Fourth Amendment protections.

Magistrates, unlike officers, have no reason to intentionally violate an individual's Fourth Amendment protections. They do not actively participate in pursuing a suspect. Magistrates and judges are intended to be neutral and impartial. For this reason, the majority felt that excluding evidence on the basis of an improperly issued warrant would have no effect on a judge or magistrate.

Justice Byron White wrote:

"If exclusion of evidence obtained pursuant to a subsequently invalidated warrant is to have any deterrent effect, therefore, it must alter the behavior of individual law enforcement officers or the policies of their departments."

Exclusion must be used on a case by case basis to ensure its effectiveness. It cannot be used broadly and treated as absolute, the majority warned. The rule requires balancing the needs of the court and the rights of the individual in every case. In U.S. v. Leon, the majority argued that the

Finally, the majority noted that evidence might be suppressed if the information provided to the magistrate as grounds for a warrant was knowingly or recklessly false. If the officer in Leon's case had attempted to mislead the judge issuing a warrant, the court may have suppressed the evidence.

Dissenting Opinion

Justice William Brennan dissented, joined by Justice John Marshall and Justice John Paul Stevens. Justice Brennan wrote that evidence obtained during an illegal search and seizure should not be used in court, regardless of whether an officer acted in good faith. The exclusionary rule only deters violations of the Fourth Amendment if it is uniformly applied, even to officers who acted "on the basis of a reasonable but mistaken belief," Justice Brennan argued.

Justice Brennan wrote:

"Indeed, the Court's "reasonable mistake" exception to the exclusionary rule will tend to put a premium on police ignorance of the law."


The Supreme Court introduced the "good faith" exception in U.S. v. Leon, which allows the court to submit evidence obtained through a faulty search warrant if the officer acted in "good faith." The ruling placed the burden in an evidentiary hearing on the defendant. Under U.S. v. Leon, defendants arguing for the suppression of evidence under the exclusionary rule would have to prove an officer was not acting in good faith at the time of the search.


  • United States v. Leon, 468 U.S. 897 (1984)
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Spitzer, Elianna. "U.S. v. Leon: Supreme Court Case, Arguments, Impact." ThoughtCo, Aug. 28, 2020, thoughtco.com/unites-states-v-leon-supreme-court-case-arguments-impact-4588287. Spitzer, Elianna. (2020, August 28). U.S. v. Leon: Supreme Court Case, Arguments, Impact. Retrieved from https://www.thoughtco.com/unites-states-v-leon-supreme-court-case-arguments-impact-4588287 Spitzer, Elianna. "U.S. v. Leon: Supreme Court Case, Arguments, Impact." ThoughtCo. https://www.thoughtco.com/unites-states-v-leon-supreme-court-case-arguments-impact-4588287 (accessed December 7, 2021).