Fourth Amendment Searches

Government action and the protected interest

The Fourth Amendment restrains government conduct. Private conduct ordinarily does not trigger it unless the private actor acts as an instrument or agent of the government. The defendant seeking suppression must show that the search invaded that defendant's own protected interest. A person cannot challenge a search solely because evidence harmful to them was found in someone else's home.

A search may occur when the government violates a reasonable expectation of privacy or physically intrudes on a constitutionally protected area to obtain information. Consider the place, the person's relationship to it and what society recognizes as private. A home receives strong protection. Open fields are generally outside the protected areas, while curtilage immediately surrounding a home is treated more like the home.

Warrant requirement

A search inside a home generally requires a warrant supported by probable cause and particularity, unless an exception applies. Probable cause is a practical probability based on the totality of the circumstances, not proof beyond a reasonable doubt. The warrant must identify the place to search and the items or persons to seize with sufficient particularity.

The executing officers generally must stay within the warrant's scope. A warrant to search for a small item does not authorize destructive searches of containers that could not hold it. Officers may seize evidence in plain view when they are lawfully present, have lawful access and its incriminating character is immediately apparent.

Common warrant exceptions

• Consent: voluntary consent from someone with actual or apparent authority can permit a search within its scope. A person may limit or withdraw consent.
• Search incident to arrest: officers may search the arrestee and the area within immediate control under the applicable rule; vehicle searches have additional limits.
• Automobile exception: probable cause that a readily mobile vehicle contains evidence or contraband can justify a search of areas and containers that may hold the object.
• Exigent circumstances: urgent needs such as preventing imminent harm or destruction of evidence may justify action without a warrant, within the emergency's scope.
• Stop and frisk: reasonable suspicion of crime permits a brief stop, and reasonable suspicion that a person is armed and dangerous can justify a limited protective pat-down for weapons.
• Inventory: a lawful standardized inventory of an impounded vehicle may be valid when not used as a pretext to investigate.

A warrant exception is not a general license to search. Identify its factual trigger and define its scope. Consent to look for a stolen bicycle may permit searching a garage but not reading private digital messages unrelated to the bicycle.

Stops, seizures and searches

A seizure of a person occurs when physical force or a show of authority restrains freedom of movement. An officer needs reasonable suspicion of criminal activity for a brief investigatory stop and probable cause for an arrest. A frisk is a separate, limited protective search based on reasonable suspicion that the person is armed and dangerous. Reasonable suspicion for a stop does not automatically authorize a full evidentiary search.

A seizure of property occurs when the government meaningfully interferes with possession. A person can be seized without a search, searched without a person being seized, or both. Analyze each event separately.

Digital and third-party information

Modern technology questions ask whether the government has intruded on a protected privacy interest, including through prolonged or revealing data collection. Do not assume that sharing information with a service provider waives every privacy interest. Apply the doctrine and any rule stated in the question, paying attention to duration, sensitivity, physical intrusion and the means used to obtain information.

Exclusion and exceptions to exclusion

Evidence obtained through an unconstitutional search may be suppressed in a criminal case when the defendant's own rights were violated. The exclusionary rule is subject to limits, including attenuation, independent source, inevitable discovery and good-faith reliance on a warrant. A Fourth Amendment violation does not automatically suppress every item later found; connect the evidence to the unlawful conduct and test the relevant doctrine.

Statements or physical evidence derived from an illegal search may be fruit of the poisonous tree, unless an exception breaks the causal connection. A later voluntary act, an independent lawful investigation or discovery that would inevitably have occurred can affect the remedy. These doctrines address admissibility, not whether the original conduct was constitutional.

MBE sequence

1. Identify government involvement and the defendant's own protected interest.
2. Decide whether the conduct is a search, seizure, or both.
3. Determine whether a warrant existed and whether it was valid and properly executed.
4. If no warrant, test each asserted exception and its scope.
5. Ask whether the defendant may seek suppression and whether an exclusionary-rule limit applies.

The most frequent reasoning error is to jump from ‘police found evidence’ to ‘the evidence is excluded.’ Constitutional violation, standing, causation and remedy are related but distinct questions. Apply them in sequence.

Identify the government action and the privacy interest

The Fourth Amendment applies to government conduct, including conduct by a private person acting as a government agent. A private search conducted independently usually does not trigger the Amendment, though later government examination can exceed the scope of what the private person already exposed. Ask who performed the search, whose privacy interest was invaded, and what area or item was searched before turning to a warrant exception.

A hotel employee opens a guest's closed suitcase for a personal reason and finds contraband, then calls police. The employee's search is private if not directed by law enforcement. If officers later open a second sealed compartment the employee never examined, that additional government search may exceed the private search's scope. The defendant must have a reasonable expectation of privacy in the place or item searched to challenge the government action.

Warrant, probable cause and particularity

A search warrant generally requires probable cause supported by oath or affirmation and must particularly describe the place to be searched and the persons or things to be seized. The issuing judge makes a practical, commonsense decision whether the facts establish a fair probability that evidence will be found in the specified place. A warrant cannot authorize an exploratory search for anything incriminating.

An affidavit says a reliable informant recently saw stolen laptops inside apartment 4B and identifies the building and unit. That supports a place-specific inference. A warrant for the entire apartment building based only on the same facts may be overbroad. Particularity and probable cause are related but distinct: a narrow warrant can still lack probable cause, and strong probable cause cannot cure a vague description.

Consent must be voluntary and within scope

Consent is an exception to the warrant requirement when voluntary under the totality of circumstances. The government need not prove the consenting person knew of the right to refuse. A person with actual or apparent common authority may consent to a shared area, but one occupant ordinarily cannot authorize a search of another's exclusive private space.

A roommate may consent to police looking in the shared living room and kitchen, but not necessarily to opening a locked suitcase that belongs to the other occupant. Scope is measured by what a reasonable person would understand from the exchange. Permission to “look around” may permit inspection of places where the object of the search could fit, but not destructive or materially different exploration.

If one physically present co-occupant expressly refuses consent, police generally cannot rely on another occupant's permission to search shared premises as to the objector. If the objector is lawfully removed for a reason unrelated to avoiding the objection, the remaining occupant's consent may be effective. Separate authority, voluntariness, scope and the effect of a present objection.

Search incident to arrest and vehicle searches

A lawful custodial arrest permits a search of the arrestee's person and the area within immediate control to remove weapons and prevent destruction of evidence. For a vehicle occupant, officers may search the passenger compartment only when the arrestee could access it at the time or it is reasonable to believe the vehicle contains evidence of the offense of arrest. A lawful arrest does not automatically authorize a full search of every nearby space.

The automobile exception permits a warrantless search of a vehicle when officers have probable cause to believe it contains contraband or evidence. The search may extend to compartments and containers where the object could be found. The exception rests on probable cause and vehicle mobility, not merely on the fact that a car is involved in an arrest. A closed container too small to hold the suspected item falls outside the permissible scope.

Stop, frisk and plain view

An officer may briefly stop a person on reasonable suspicion of criminal activity. A frisk requires a separate reasonable belief that the person is armed and dangerous, and is a limited pat-down for weapons. During a lawful frisk, an object may be seized if its identity as contraband is immediately apparent through lawful touch without further manipulation. A hunch or an exploratory squeeze is insufficient.

Plain-view seizure requires a lawful vantage point, lawful access to the object and probable cause that the item is contraband or evidence. Seeing an object from a lawful place does not itself authorize entry to retrieve it if officers lack lawful access. Keep observation and seizure as separate steps.

Exclusion, standing and exceptions

The exclusionary rule can bar evidence obtained through an unconstitutional search, as well as certain derivative evidence. It is subject to doctrines such as independent source, inevitable discovery, attenuation and good-faith reliance on a warrant later found defective. These doctrines ask whether suppression would meaningfully deter police misconduct and whether the evidence was obtained through a sufficiently independent or weakened causal path.

A defendant generally may challenge a search only when the defendant's own Fourth Amendment rights were violated. A passenger may challenge an unlawful stop of the vehicle but does not automatically have a privacy interest in the driver's trunk. A guest who stays overnight may have a privacy interest in the host's home; a brief commercial visitor usually has a weaker claim. Do not assume that a defendant can suppress evidence merely because it incriminates them.

On a problem, analyze in this order: government action; protected privacy interest; warrant and its limits; any exception; scope; and remedy. If an exception fails, say which requirement is missing. If the defendant lacks a personal privacy interest, the search may still be unlawful as to someone else, but that defendant ordinarily cannot obtain suppression on that basis.