9.2 Fourth Amendment: Search, Seizure & Exclusionary Rule
Key Takeaways
- Fourth Amendment protections apply exclusively to government action where an individual maintains a subjective expectation of privacy that society recognizes as objectively reasonable (Katz) or where the government physically intrudes on a protected area to gather evidence (Jones/Jardines).
- Standing to contest a search under Rakas requires a personal privacy interest; owners, resident tenants, and overnight guests hold standing, while short-term commercial visitors and vehicular passengers claiming no property interest lack standing.
- A search warrant requires Probable Cause under the totality of the circumstances (Gates), an oath or affirmation, a neutral and detached magistrate, and particularity describing the places to be searched and items to be seized.
- Warrantless searches are per se unreasonable unless falling within established ESCAPIST exceptions: Exigent circumstances, SILA (Chimel wingspan, Gant vehicle restrictions), Consent, Automobile exception (PC for vehicle allows searching all containers), Plain view, Inventory, Special needs, and Terry stop-and-frisk.
- The Exclusionary Rule suppresses unconstitutionally obtained evidence in the prosecution's case-in-chief; exceptions include Independent Source, Inevitable Discovery, Attenuation of Taint, and the Leon Good Faith reliance exception.
9.2 Fourth Amendment: Search, Seizure & Exclusionary Rule
The Fourth Amendment guarantees the right of the people to be secure in their persons, houses, papers, and effects against unreasonable searches and seizures, and mandates that no warrants shall issue, but upon probable cause, supported by oath or affirmation, and particularly describing the place to be searched, and the persons or things to be seized.
1. Fourth Amendment Analytical Framework
To determine whether evidence must be suppressed under the Fourth Amendment, courts follow a rigorous multi-step inquiry:
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| FOURTH AMENDMENT SUPPRESSION FLOWCHART |
| |
| STEP 1: GOVERNMENT ACTION? |
| - Conduct by police, state actors, or private citizens directed by police.|
| -> If NO: Fourth Amendment does NOT apply. |
| -> If YES: Proceed to Step 2. |
| |
| STEP 2: REASONABLE EXPECTATION OF PRIVACY (REP) OR PHYSICAL TRESPASS? |
| - Katz Test: Subjective privacy expectation + Objectively reasonable. |
| - Jones/Jardines: Physical intrusion/trespass onto protected area to |
| gather information. |
| - Standing: Does THIS defendant have a personal privacy interest? |
| -> If NO: No search; no standing to challenge. |
| -> If YES: Proceed to Step 3. |
| |
| STEP 3: SEARCH WARRANT SATISFACTION? |
| - Was there a valid warrant supported by Probable Cause & Particularity |
| issued by a Neutral Magistrate? |
| -> If YES: Evidence admissible (unless execution defective). |
| -> If NO: Proceed to Step 4. |
| |
| STEP 4: DOES A RECOGNIZED WARRANT EXCEPTION (ESCAPIST) APPLY? |
| - Exigent / SILA / Consent / Automobile / Plain View / Inventory / |
| Special Needs / Terry Stop & Frisk. |
| -> If YES: Search is constitutional; evidence admissible. |
| -> If NO: Proceed to Step 5. |
| |
| STEP 5: DOES AN EXCLUSIONARY RULE EXCEPTION APPLY? |
| - Independent Source, Inevitable Discovery, Attenuation, Leon Good Faith. |
| -> If YES: Evidence admissible despite constitutional defect. |
| -> If NO: EVIDENCE MUST BE SUPPRESSED from prosecution case-in-chief. |
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2. Thresholds: Government Action, Privacy & Standing
Government Action Requirement
The Fourth Amendment applies strictly to actions by government officials (federal, state, and municipal police, public school officials) or private individuals acting as agents or instruments of the government. Wholly private searches do not trigger the Fourth Amendment (Burdeau v. McDowell).
The Katz and Jones Search Standards
- Expectation of Privacy (Katz v. United States): A search occurs when government conduct violates a person's: (a) actual, subjective expectation of privacy, and (b) that expectation is one that society recognizes as objectively reasonable.
- Physical Trespass / Property-Based Search (United States v. Jones, Florida v. Jardines): A search also occurs whenever the government physically intrudes or trespasses upon a constitutionally protected area (person, house, papers, effects, curtilage) with the objective purpose of obtaining information, regardless of whether there was a reasonable expectation of privacy.
Areas Lacking a Reasonable Expectation of Privacy (No Search)
Certain categories are deemed exposed to the public, lacking any reasonable expectation of privacy under the Third-Party Doctrine and Open Fields doctrine:
- Open Fields (Oliver v. United States): Unoccupied or undeveloped areas outside the curtilage of a home do not receive Fourth Amendment protection, even if fenced, gated, or marked with "No Trespassing" signs. (Note: The curtilage—the land immediately surrounding and associated with the home—enjoys full Fourth Amendment protection).
- Bank Records (United States v. Miller): Financial records voluntarily disclosed to commercial banks.
- Dialed Telephone Numbers (Smith v. Maryland): Numbers captured via pen registers or dialed data.
- Garbage Left at the Curb (California v. Greenwood): Trash placed outside the curtilage for collection.
- Physical Characteristics: Voice exemplars, handwriting samples, physical appearance.
- Airspace Surveillance (California v. Ciraolo): Naked-eye visual surveillance from lawful, navigable airspace.
- Canine Sniffs in Public (Illinois v. Caballes): Dog sniff of the exterior of a vehicle during a lawful traffic stop is not a search. (However, bringing a trained drug dog onto the curtilage / front porch of a home is a search under Florida v. Jardines).
- Cell-Site Location Information (Carpenter v. United States): Accessing historical cell-site records (CSLI) spanning seven days or more constitutes a search requiring a warrant.
Fourth Amendment Standing (Rakas v. Illinois)
A defendant may challenge a search only if their own personal constitutional rights were violated.
- Automatic Standing: Homeowners, tenants residing in a dwelling, and overnight guests (Minnesota v. Olson).
- No Standing: Short-term commercial visitors who have no personal connection to the premises (Minnesota v. Carter); passengers in an automobile who claim no ownership or possessory interest in the car or the items seized (Rakas v. Illinois). Note: A passenger does have standing to contest the unconstitutional seizure of their person during an unlawful traffic stop (Brendlin v. California).
3. The Warrant Requirement & Probable Cause
A valid search warrant requires three constitutional pillars:
- Probable Cause (PC): Under Illinois v. Gates, probable cause is evaluated under the totality of the circumstances. It requires a fair probability that contraband or evidence of a crime will be found in a particular location. An informant's tip is evaluated by considering the informant's veracity, reliability, and basis of knowledge.
- Neutral and Detached Magistrate: The issuing judicial officer must be completely neutral (cannot be a prosecutor, police officer, or magistrate receiving financial incentives for issuing warrants).
- Particularity (Groh v. Ramirez): The warrant must describe with reasonable precision the specific place to be searched and the specific persons or items to be seized.
Knock and Announce Rule (Wilson v. Arkansas)
Police executing a search warrant must knock, announce their identity and authority, and wait a reasonable time before forcible entry, unless officers have reasonable suspicion that knocking would be dangerous, futile, or inhibit the effective investigation (risk of evidence destruction).
- Crucial Remedy Limitation (Hudson v. Michigan): A violation of the Knock and Announce rule does NOT trigger the Exclusionary Rule. Evidence seized remains admissible.
4. Warrant Exceptions (The ESCAPIST Matrix)
Warrantless searches are presumptively unreasonable under the Fourth Amendment unless they fall squarely within one of eight established exceptions:
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| WARRANT EXCEPTIONS (ESCAPIST) |
| |
| E - EXIGENT CIRCUMSTANCES / HOT PURSUIT |
| - Hot pursuit of fleeing felon (Warden v. Hayden). |
| - Imminent destruction of evidence (Kentucky v. King). |
| - Emergency aid / immediate danger to human safety (Brigham City). |
| |
| S - SEARCH INCIDENT TO LAWFUL ARREST (SILA) |
| - Arrestee's person and grab-area / wingspan (Chimel). |
| - Vehicle SILA (Gant): (1) Arrestee unsecured & within reaching |
| distance, OR (2) Reasonable to believe evidence of CRIME OF ARREST |
| is located in vehicle. (Digital data on cell phones EXCLUDED). |
| |
| C - CONSENT |
| - Voluntary under totality of circumstances (Schneckloth). |
| - Third-party actual or apparent authority (Matlock, Rodriguez). |
| - Physically present objecting co-occupant prevails (Randolph). |
| |
| A - AUTOMOBILE EXCEPTION |
| - Probable cause vehicle contains evidence/contraband (Carroll). |
| - Allows search of entire vehicle and ANY container (Acevedo) that |
| could conceal the object. Does NOT extend to home's curtilage. |
| |
| P - PLAIN VIEW |
| - Lawfully present + Lawful right of access. |
| - Incriminating character IMMEDIATELY APPARENT (Horton / Hicks). |
| |
| I - INVENTORY SEARCH |
| - Standardized police administrative policy for impounded property. |
| |
| S - SPECIAL NEEDS / ADMINISTRATIVE |
| - Public schools (reasonable suspicion under T.L.O.), border searches,|
| fixed sobriety checkpoints (Edmond: not general crime control). |
| |
| T - TERRY STOP AND FRISK |
| - Stop: Reasonable Articulable Suspicion (RAS) crime is afoot. |
| - Frisk: RAS suspect is ARMED and dangerous (outer clothing pat-down).|
| - Plain Feel: Contraband identified immediately without manipulation. |
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Vehicle SILA vs. Automobile Exception Distinction
A frequent MBE trap confuses Search Incident to Lawful Arrest in a vehicle (Gant) with the Automobile Exception (Carroll/Acevedo):
| Feature | Vehicle Search Incident to Arrest (Gant) | Automobile Exception (Carroll / Acevedo) |
|---|---|---|
| Prerequisite | Lawful custodial arrest of recent occupant. | Probable Cause that vehicle contains contraband. |
| Permissible Scope | Passenger compartment and unlocked containers within reaching distance (NO trunk). | Entire vehicle, including trunk, locked glove box, and all containers. |
| Arrestee Status | Limited if arrestee is handcuffed/secured in police cruiser. | Irrelevant whether driver is arrested, handcuffed, or absent. |
5. Stop and Frisk (Terry Doctrine)
Under Terry v. Ohio, police may conduct brief, investigatory street encounters without a warrant or probable cause based on lesser standards of suspicion:
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| THE TERRY DOCTRINE TWO-STEP |
| |
| LEVEL 1: TERRY STOP (Seizure of Person) |
| - Standard: REASONABLE ARTICULABLE SUSPICION (RAS) that criminal activity |
| is afoot, based on specific and articulable facts. |
| - Scope: Brief, temporary investigatory detention to verify or dispel. |
| - Informant Tips: Anonymous tip requires corroboration of predictive info |
| (Florida v. J.L. vs. Navarette). Unprovoked flight in high-crime area |
| supports RAS (Wardlow). |
| |
| LEVEL 2: TERRY FRISK (Protective Search for Weapons) |
| - Standard: Independent RAS that the suspect is ARMED AND DANGEROUS. |
| - Scope: Strictly limited to a pat-down of outer clothing for weapons. |
| - Plain Feel Doctrine (Minnesota v. Dickerson): If during a lawful frisk, |
| the officer feels an object whose contour or mass makes its identity as |
| contraband IMMEDIATELY APPARENT without squeezing, manipulating, or |
| sliding, the officer may seize it. |
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6. The Exclusionary Rule & Fruit of the Poisonous Tree
Under Mapp v. Ohio, evidence obtained in violation of the Fourth Amendment is excluded from the prosecution's case-in-chief. Derivative evidence discovered as a direct or indirect result of the unlawful search is also suppressed under the Fruit of the Poisonous Tree doctrine (Wong Sun v. United States).
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| EXCLUSIONARY RULE EXCEPTIONS MATRIX |
| |
| EXCEPTION STANDARD / LEGAL TEST |
| -------------------- -------------------------------------------------- |
| INDEPENDENT SOURCE Evidence was discovered through a wholly independent|
| source untainted by the initial illegal conduct |
| (Murray v. United States). |
| |
| INEVITABLE DISCOVERY Prosecution proves by a preponderance of the |
| evidence that the evidence would have inevitably |
| been discovered by lawful means (Nix v. Williams). |
| |
| ATTENUATION OF TAINT The causal link between illegal conduct and evidence|
| is severed by: (1) temporal proximity, (2) inter- |
| vening circumstances, and (3) lack of flagrancy |
| (Utah v. Strieff). |
| |
| GOOD FAITH EXCEPTION Police relied in objective good faith on a search |
| (Leon / Sheppard) warrant issued by a magistrate, even if the warrant |
| is subsequently invalidated. |
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The Four Leon Good Faith Exceptions
Good faith reliance will NOT save evidence from suppression if:
- The supporting affidavit contained knowing or reckless falsehoods (Franks v. Delaware);
- The issuing magistrate wholly abandoned their neutral and detached judicial role;
- The affidavit was so lacking in indicia of probable cause that official belief in its existence was entirely unreasonable ("bare-bones affidavit"); or
- The warrant was so facially deficient in particularity that executing officers could not reasonably presume it to be valid.
Limitations on the Scope of Exclusion
The Exclusionary Rule does not apply to: Grand jury proceedings, civil deportation hearings, parole revocation proceedings, or for the purpose of impeaching the defendant's direct trial testimony (United States v. Havens).
Police officers arrested a motorist on an outstanding bench warrant for failing to pay a municipal traffic fine. The officers handcuffed the motorist and secured him in the locked rear compartment of the patrol vehicle. Without obtaining a warrant, an officer thoroughly searched the passenger compartment of the motorist's vehicle and discovered an unregistered firearm hidden under the driver's seat. In a subsequent federal prosecution for unlawful possession of a firearm, the defendant moves to suppress the weapon. How should the court rule?
Police officers obtained a valid search warrant authorized to search a suspect's detached garage for a stolen 65-inch television. While executing the warrant inside the garage, an officer opened a small metal tin measuring 3 inches by 5 inches located on a workbench. Inside the tin, the officer found twenty plastic baggies containing illicit cocaine. The suspect was charged with possession of a controlled substance with intent to distribute and moved to suppress the cocaine. Is the cocaine admissible under the plain view doctrine?
Two roommates shared a two-bedroom apartment, with each roommate possessing an individual private bedroom and sharing the living room and kitchen. Police arrived at the apartment without a warrant and asked to search the premises for stolen electronics. Roommate A, who was standing in the doorway, verbally objected to any search and refused entry. Roommate B stepped forward and verbally gave the officers permission to search the common living room. Over Roommate A's continued objections, the officers entered and found a stolen laptop in the living room. Was the warrantless search lawful as to Roommate A?
An officer stopped a pedestrian late at night in a high-crime neighborhood after observing the pedestrian loitering outside a convenience store. The officer asked the pedestrian for identification, but before the pedestrian could respond, the officer conducted a pat-down frisk of the pedestrian's outer jacket, feeling a hard, rigid object that the officer immediately identified as a handgun. The officer arrested the pedestrian. At a suppression hearing, the officer conceded that he had no specific factual basis to believe the pedestrian was armed or engaging in criminal activity prior to the stop. What is the appropriate ruling on the motion to suppress the handgun?