United States v. Leon
E127319
United States v. Leon is a 1984 U.S. Supreme Court decision that established the "good faith" exception to the exclusionary rule in Fourth Amendment search and seizure cases.
All labels observed (1)
| Label | Occurrences |
|---|---|
| United States v. Leon canonical | 8 |
How this entity was disambiguated
This entity first appeared as the object of triple T1076329 — resolving that mention is where its identity was fixed. The disambiguator weighed these candidate entities and picked the highlighted one (or “None”, minting a new entity). This is how homonymy is resolved: the same surface form can point to different entities.
NED1
Entity disambiguation (via context triple)
gpt-5-mini-2025-08-07
Target entity: United States v. Leon Context triple: [Fourth Amendment to the United States Constitution, landmarkCase, United States v. Leon]
-
A.
Illinois v. Gates
Illinois v. Gates is a 1983 U.S. Supreme Court decision that established the "totality of the circumstances" test for determining whether an informant’s tip provides probable cause for issuing a search warrant.
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B.
Miranda v. Arizona
Miranda v. Arizona is a landmark 1966 U.S. Supreme Court case that established the requirement for police to inform criminal suspects of their rights to remain silent and to have an attorney present during custodial interrogations.
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C.
Escobedo v. Illinois
Escobedo v. Illinois is a landmark 1964 U.S. Supreme Court case that expanded the Sixth Amendment right to counsel during police interrogations and helped lay the groundwork for the later Miranda warnings.
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D.
Mapp v. Ohio
Mapp v. Ohio is a landmark 1961 U.S. Supreme Court case that applied the exclusionary rule to the states, holding that evidence obtained in violation of the Fourth Amendment cannot be used in state criminal prosecutions.
-
E.
Dickerson v. United States
Dickerson v. United States is a 2000 U.S. Supreme Court case that reaffirmed the constitutional basis of Miranda warnings and held that Congress could not overrule Miranda v. Arizona by statute.
- F. None of above. chosen
- G. Unsure - the case is ambiguous/there is not enough information to decide.
NED2
Entity disambiguation (via description)
gpt-5-mini-2025-08-07
Target entity: United States v. Leon Target entity description: United States v. Leon is a 1984 U.S. Supreme Court decision that established the "good faith" exception to the exclusionary rule in Fourth Amendment search and seizure cases.
-
A.
Illinois v. Gates
Illinois v. Gates is a 1983 U.S. Supreme Court decision that established the "totality of the circumstances" test for determining whether an informant’s tip provides probable cause for issuing a search warrant.
-
B.
Miranda v. Arizona
Miranda v. Arizona is a landmark 1966 U.S. Supreme Court case that established the requirement for police to inform criminal suspects of their rights to remain silent and to have an attorney present during custodial interrogations.
-
C.
Escobedo v. Illinois
Escobedo v. Illinois is a landmark 1964 U.S. Supreme Court case that expanded the Sixth Amendment right to counsel during police interrogations and helped lay the groundwork for the later Miranda warnings.
-
D.
Mapp v. Ohio
Mapp v. Ohio is a landmark 1961 U.S. Supreme Court case that applied the exclusionary rule to the states, holding that evidence obtained in violation of the Fourth Amendment cannot be used in state criminal prosecutions.
-
E.
Dickerson v. United States
Dickerson v. United States is a 2000 U.S. Supreme Court case that reaffirmed the constitutional basis of Miranda warnings and held that Congress could not overrule Miranda v. Arizona by statute.
- F. None of above. chosen
Statements (49)
| Predicate | Object |
|---|---|
| instanceOf |
Fourth Amendment case
ⓘ
United States Supreme Court case ⓘ criminal procedure case ⓘ |
| alsoKnownAs | Leon good faith exception case ⓘ |
| appliesTo | evidence obtained under a facially valid search warrant later found unsupported by probable cause ⓘ |
| areaOfLaw |
criminal law
ⓘ
criminal procedure ⓘ |
| arguedDate | 1983-01-17 ⓘ |
| citation | 468 U.S. 897 ⓘ |
| concurrenceBy | Harry A. Blackmun ⓘ |
| country |
United States
ⓘ
linked to:
United States of America
|
| court | Supreme Court of the United States ⓘ |
| decisionDate | 1984-07-05 ⓘ |
| dissentBy |
John Paul Stevens
ⓘ
Thurgood Marshall ⓘ William J. Brennan Jr. ⓘ |
| doesNotApplyWhen |
the magistrate wholly abandons his judicial role
ⓘ
the warrant is based on an affidavit so lacking in indicia of probable cause as to render official belief in its existence entirely unreasonable ⓘ the warrant is so facially deficient that the executing officers cannot reasonably presume it to be valid ⓘ |
| established | good faith exception to the exclusionary rule ⓘ |
| fullName | United States v. Leon ⓘ |
| goodFaithExceptionDefinedAs | an exception allowing admission of evidence when police reasonably rely on a warrant issued by a neutral magistrate ⓘ |
| holding | The Fourth Amendment exclusionary rule does not require suppression of evidence obtained by officers acting in objectively reasonable reliance on a search warrant later found to be invalid. ⓘ |
| impact | narrowed the scope of the exclusionary rule in federal and state courts ⓘ |
| joinedByInMajority |
Lewis F. Powell Jr.
ⓘ
Sandra Day O'Connor ⓘ
linked to:
Sandra Day O’Connor
Warren E. Burger ⓘ William H. Rehnquist ⓘ William J. Brennan Jr. ⓘ |
| jurisdiction | federal ⓘ |
| legalSubject |
Fourth Amendment to the United States Constitution
ⓘ
exclusionary rule ⓘ search and seizure ⓘ |
| limitsExclusionaryRule | yes ⓘ |
| majorityOpinionBy |
Byron White
ⓘ
linked to:
Byron R. White
|
| page | 897 ⓘ |
| party |
Alberto Leon
ⓘ
United States ⓘ
linked to:
United States of America
|
| rearguedDate | 1984-03-28 ⓘ |
| reasoningIncludes |
the costs of exclusion may outweigh its deterrent benefits when officers act in objective good faith
ⓘ
the exclusionary rule is a judicially created remedy, not a personal constitutional right ⓘ |
| relatedDoctrine |
exclusionary rule
ⓘ
probable cause ⓘ |
| reporter | United States Reports ⓘ |
| subsequentCitationBy |
Arizona v. Evans
ⓘ
Herring v. United States ⓘ Illinois v. Krull ⓘ |
| volume | 468 ⓘ |
| year | 1984 ⓘ |
How these facts were elicited
The pipeline generated the facts above by prompting gpt-5.1 with this entity's name + description and the instruction below.
Instruction
You are a knowledge base construction expert. Given a subject entity and a description of it, return factual statements that you know for the subject as a JSON list of dictionaries(triples), where keys must be "subject", "predicate" and "object". The number of facts may be very high, between 25 to 50 or more, for very popular subjects. For less popular subjects, the number of facts can be very low, like 5 or 10. # Requirements - If you don't know the subject at all, return an empty list. - If the subject is not a named entity, return an empty list. - Include at least one triple where predicate is "instanceOf". - Do not get too wordy. - Separate several objects into multiple triples with one object.
Input
Subject: United States v. Leon Description of subject: United States v. Leon is a 1984 U.S. Supreme Court decision that established the "good faith" exception to the exclusionary rule in Fourth Amendment search and seizure cases.
Referenced by (8)
Full triples — surface form annotated when it differs from this entity's canonical label.