## Facts

- Burbank, California police received information from a confidential informant indicating that several individuals were involved in narcotics trafficking.
- Officers conducted surveillance, connected additional suspects (including Alberto Antonio Leon) to the suspected activity, and prepared a warrant application relying on surveillance and informant reports.
- An officer submitted an affidavit seeking authority to search multiple residences and automobiles for narcotics and related evidence.
- Deputy district attorneys reviewed the application, and a state-court judge issued a facially valid search warrant.
- Police executed the warrant and seized substantial quantities of drugs and other evidence.
- Leon and others were federally indicted and moved to suppress, arguing the affidavit failed to establish probable cause under the Fourth Amendment.

## Issues

1. Whether the Fourth Amendment exclusionary rule requires suppression of evidence obtained by officers who reasonably relied on a search warrant issued by a detached and neutral magistrate, when the warrant is later found unsupported by probable cause.

## Decision

- The Supreme Court reversed (6–3) and recognized a good-faith exception to the exclusionary rule.
- The Court held that evidence need not be excluded when officers act in objectively reasonable reliance on a warrant issued by a detached and neutral magistrate, even if the warrant is later found invalid for lack of probable cause.
- The Court treated the exclusionary rule as a judicially created remedy aimed primarily at deterring police misconduct, not as a personal constitutional right.
- Applying a cost–benefit analysis, the Court concluded suppression has little deterrent value where officers reasonably rely on a warrant; the principal error, if any, lies with the issuing magistrate.
- The Court found the officers’ reliance objectively reasonable in this case and held suppression unwarranted (assuming, without deciding, that probable cause was lacking).

## Legal Principles

- The exclusionary rule is a deterrent remedy; it applies where its deterrent benefits outweigh its social costs.
- Evidence obtained under a warrant later found invalid is generally admissible if officers’ reliance on the warrant was objectively reasonable.
- The good-faith exception does not apply when:
  - The issuing magistrate was misled by an affidavit containing information the affiant knew was false or would have known was false except for reckless disregard for the truth.
  - The magistrate wholly abandoned the judicial role and was not a detached and neutral decision maker.
  - The affidavit was so lacking in indicia of probable cause that belief in probable cause was entirely unreasonable.
  - The warrant was so facially deficient (including failure to particularize place or items) that executing officers could not reasonably presume it valid.

## Conclusion

The Court held that the Fourth Amendment does not require suppression when officers execute a facially valid warrant in objectively reasonable reliance on a neutral magistrate’s issuance, establishing a good-faith exception that limits exclusion to cases where suppression can meaningfully deter culpable police conduct.


United States v. Leon, 468 U.S. 897 (1984)