4th Amendment
Katz v United States (1967)
Facts of the Case
Katz gave gambling info over the phone to clients
Feds used eavesdropping device on public phone booth to record him
Katz arrested under illegal transmission of wagering information
Appeared and COurt rejected as there was no physical intrusion into the phone booth
Question
Does the Fourth Amendment protection against unreasonable searches and seizures require the police to obtain a search warrant in order to wiretap a public pay phone?
Conclusion
Yes
Katz had protection as 4th amendment protects “people not places”
Harlan introduces idea of reasonable expectation of 4th amendment protection
Kyllo v. US
Facts of the Case
Dept. of Interior agent used thermal imaging device to scan Kyllo’s triplex
Looking to see if he was growing weed
Based on seeing hot spots warrant was issued
Found weed
Kyllo was indicted
Court of appeals said Kyllo had no reasonable expectation of privacy
Question
Does the use of thermal-imaging device to detect relative amounts of heat emanating from a private home constitute an unconstitutional search in violation of the 4th Amendment?
Conclusion
Yes
Where, as here, the government uses a device that is not in general public use, to explore details of the home that would previously have been unknowable without physical intrusion, the surveillance is a search and is presumptively unreliable without a warrant”
Carpenter v. US (2018)
Facts of the Case
2011 police arrested men in connected with armed robberies
One man gave information on others to FBI
FBI uses this to obtain transactional records of other 3
Under Stored Communications Act
Based on this information charged Carpenter with aiding and abetting robbery
Question
Does the warrantless search and seizure of cell phone records, which include the location and movements of cell phone users, violate the Fourth Amendment?
Conclusion
Yes
4th amendment protects expectations of privacy
Declined to extend 3rd party doctrine to cell-site location information which implicates privacy concerns
Applies to voluntary exposure
Government needs warrant to access cell-site location information
Fourth Amendment – Searches and Seizures
Overview of Fourth Amendment
Full enjoyment of the rights of personal security, personal liberty, and private property by prohibiting unreasonable searches and seizures
Warrants must be supported by probable cause
Places of search must be specified in the warrant
There are some exceptions
Incident to arrest
By administrative searches justified by special needs beyond normal need for law enforcement
Historical Background
Long-standing in English political thought
Every man’s house is his castle
Landmark English cases: Entick v Carrington and Wilkes v Wood
Scope of Protected Rights
Overview of Unreasonable Searches and Seizures
Must be probable cause and particularized description of what’s being searched
Harris v US
Reasonable warrantless search of a 4 room apartment pursuant to the arrest of a man
Chimel v California
4th amendment was reaction to the general warrant and warrantless searches that alienated colonists
Police must, whenever practicable, obtain advance judicial approval of search and seizures through a warrant procedure
1970s
Court divided on which standard to use
1992: reasonableness approach over warrants-with-narrow exceptions
Early Doctrine on the Fourth Amendment
Must be a search and seizure with subsequent attempt to use the seized judicially for 4th amendment to apply
Olmstead v US
Didn’t cover wiretapping because defendant's premises had not been physically invaded
There was an invasion, a technical trespass, the 4th amendment applied to electronic surveillance
Only applied to tangible items
Federal Communications Act
Limited government wiretapping
Nardone v. US
Wiretapping violated FCA section 605
Katz and Reasonable Expectation of Privacy Test
Premise that property interest control the right of the government to search and seize has been discredited
4th amendment for privacy not property
Depends on if area was one in which there was reasonable expected of freedom from government intrusion
Kyllo v US
Invalidated warrantless use of thermal imaging devices at a private home
4th amendment to secure the privacy of life against arbitrary power
Place obstacles in the way of a too permeating police surveillance
Individual has no legitimate expectation of privacy in information he voluntarily provides to third parties
Balancing act
Assessing the nature of a particular practice and the likely extent of its impact on the individual’s sense of security balanced against the utility of the conduct as a technique of law enforcement
Two tiered scale
Whether 4th amendment protected an interest
If yes, a warrant is required
Subject to narrowly defined exceptions
Berger v New York
Conversations could not be seized in the 4th amendment sense
Wiretapping is a search and seizure within the meaning of the 4th amendment
Must be showing of probable cause and the warrant must particularly describe the place to be searched and the persons or things to be seized
Disallowing general warrants
Current Doctrine on Searches and Seizures
US v Jones
Whether the attachment of GPS to a car used by suspected narcotics dealer was a search
Court says violated rights
Common law
Attaching device was a physical intrusion into Jones's Private property
Carpenter v US
4th amendment when gov. action violates individuals’ reasonable expectation of privacy in the whole of their physical movements
Open Fields Doctrine
Hester v US
4th did not protect open fields
Police could search pastures, wooded areas, open water, and vacant lots without warrants and probable cause
Oliver v US
Open field exception for fields that are fenced or posted
Seizure of Property
Inspections
First began as only under criminal law
Camara v. Municipal Court + See v City of Seattle
Administrative inspections require warrants if occupant objects
Marshall v Barlow’s Inc.
OSHA provision that authorized fed inspectors to search work areas without a warrant was unconstitutional
Chipped away at by Donovan v. Dewey
Warrantless searches served regulatory purposes
Industries with a history of government oversight that no reasonable expectation of privacy exists
Liquor sales, firearms dealing, mining, and automobile junkyard
Three pronged test (warrantless search rationale)
Substantial government interest informing the regulatory scheme
Warrantless inspection is necessary to further the government's purpose
Inspection program provides a constitutionally adequate substitute for a warrant
Cady v Dumbrowski
Police engage in community caretaking functions that are divorced from the detection, investigation, or acquisition of evidence relating to the violation of criminal statutes
Property Subject to Seizure
Gouled v US
Limited property subject to seizure to contraband and the instruments/fruits of a crime
Warden v Hayden
Evidentiality items can be obtained without a warrant where special needs of the government are shown
Items seized not testimonial in nature
Property Seizures and Self-Incrimination Protections
Boyd v US
Facts: Illegally imported goods and subject to forfeiture
Seizures of items to be used only as evidence was impermissible
Unreasonable Seizures of Persons
Protect against arbitrary arrests
If police are to do warrantless search must have probable cause
Consider the totality of the circumstances examining events leading up to the arrest
Probable Cause
Overview of Probable Cause
Draper v US
Begun line of cases
Informant gives police information about individual with narcotics
FBI had probable cause to arrest him
Jones v US
Affidavit set forth reliability of the informer and sufficient detail to indicate tip was based on personal observation
Totality test
Aguilar v Texas
Insufficient an affidavit that merely asserted that the police had reliable information from a credible person
Must present two types of basis
Circumstances from which the informant concluded evidence was present
Present information that would permit the magistrate to decide whether or not informant was trustworthy
Used this in Spinelli v US
Returned to totality test in Illinois v Gates
Defunct of two-part test: treated informants reliability and basis for knowledge as independent requirements
Probable Cause Doctrine
US v Ventresca
Belief based on personal observations and substantial amount of personal observations that supported stated belief
Sufficient for probable cause
Non-traditional Contexts and Probable Cause
When material may be protected under first amendment, gov has to observe more exacting standards
Ex. Marcus v Search Warrant
Later: with adequate safeguards, no pre-seizure adversary hearing on the issue of obscenity is required if a film is seized as to preserve evidence
Seizure cannot be justified as incidental to arrest
Stanford v Texas
Warrants must particularly describe the things to be seized
Warrant Requirement
Overview
Emphasis on the necessity of warrants places the judgment of an independent magistrate between law enforcement and privacy of citizens
Limits invasion to the person, the place, and evidence sought
Neutral and Detached Magistrate
To keep protections of citizens
Must also be capable of determining whether probable cause exists
Probable Cause Requirement
Definition is judicial construct
Applicant for a warrant much present to magistrate facts sufficient to enable officer to make determination
Whether affiant has reasonable grounds, law was violated, and facts are reasonable so that another would deem search justified
Particularity Requirement
Nothing left up to discretion of officer executing the warrant
Limits scope of search
Knock and Announce Rule
Must give notice that you are there (rule of common law)
Ker v California
Rule of announcement is constitutional requirement
Wilson v Arkansas
Party of the reasonableness inquiry
Other Considerations When Executing a Warrant
Amendment violated when media and 3rd parties get involved
Exceptions to Warrant Requirement
Overview
Vast majority of searches and seizures happen without warrants
Consent Searches
Right can be waved if one consents to a search of person or premise
Burden is on prosecution to prove the voluntariness of the consent
Not consensual if officer asserts official status or gets it through deception
Questioning consent if its given by a third party
Permissible if officer has reasonable belief that 3rd party had common authority and could consent
If co-occupant of space denies search, searching would be unreasonable
Exigent Circumstances and Warrants
Exigencies of a the situation: make the needs of law enforcement so compelling that the warrantless search is objectively reasonable
Look at whether there was an emergency
Hot pursuit of a fleeing suspect
Prevention of imminent destruction
Court looks at case by case basis
Warrantless Searches Dependent on Probable Cause
Search Incident to Arrest Doctrine
Question of the scope of the search
Must be additionally justification
Disavowed case by case approach of searches made post-arrest
Embraced categorical evaluations to post-arrest searches
Riley v. California
Didn’t apply Robinson to search of digital data in a cell phone of arrestee
Before police can search a cell phone incident to an arrest the police must get a warrant
Birchfield v North Dakota
Looked at breathalyzers and blood tests
Unreasonable under the search incident to arrest exception to the warrant requirement
Weighing privacy interests with state interest
Blood test more serious privacy concern
Chimel v California
Narrower view
When arrest is made, reasonable for arresting officer to search the person arrested in order to remove any weapons that the latter might seek to use in order to resist arrest itself frustrated
Reasonable for for arresting officer to search and seize evidence on arrestees person
Officers can search areas within the arrestees immediate control to alleviate any threat posed by the arrestee
Protective sweep may be undertaken
Belton allows vehicle search incident to the arrest of occupant
Only if arrestee is within reaching distance of the passenger compartment at time of search (Arizona v Gant)
Vehicle Searches
Early days – court created exception
Holding in Carroll v US
Vehicles may be searched without warrants
initially court limits Carroll – impermissible the warrantless seizure of parked automobile merely because it is movable
Next
Reduced privacy rationale
Excluding Evidence
Exclusionary Rule and Evidence
Alternatives to the exclusionary rule: illegal search may be criminally actionaly – police subject to discipline for these actions
Civil remedies are available
Have tort action available if person is illegally arrested
Officer can have defense of good faith
Not based on subjective intent of the officer
Officers are entitled to qualified immunity
Adoption of Exclusionary Rule
Boyd v US
Compulsory production of business papers – Court likened to search and seizure
Analogized the fifth amendment self-incrimination provision to the 4th amendment
Weeks v US
Convicted under two warrantless searches
Court held evidence should have been excluded
Exclusionary rule under Self-Incrimination Clause of 5th
Wolf v Colorado
Freedom from unreasonable searches and seizures was a fundamental right as to be protected under the Due Process Clause
Rochin standard (illegally breaking in to remove bodily content is unconstitutional) limited in Irvine v California
Rochin still remained standard in later cases
Mapp v Ohio
Exclusionary rule applied to the states
Logically and constitutionally necessary
Standards of legality of search between state and fed now the same
Tied rule to fourth
Purpose of rule is to deter
Court emphasized high costs of enforcing rule to exclude reliable and trustworthy evidence even when there were violations
Exclusionary rule is inapplicable in parole revocation hearings
Violation of knock-and-announce rule does not require suppression of the evidence gathered pursuant to a search
Curtailment of rule in US v Leon
Exception as a result of officer’s good-faith reliance on a warrant – later found defective – issued by a detached and neutral magistrate
Applied this standard in Mass. v. Sheppard
To trigger rule police conduct must be sufficiently deliberate that exclusion can meaningfully deter it and sufficiently culpable
Standing to Suppress Illegal Evidence
Standing principle: required of one who seeks to challenge legality of a search as the basis for suppressing relevant evidence that they allege that they were the victim of invasion of privacy
Jones v US
Held that a person could establish standing to challenge search/seizure where that person was legitimately on the premises as a guest or invitee of the owner of the premise
Rakas v IL
To challenge a search, person must assert a personal interest protected by 4th
Good Faith Exception to Exclusionary Rule
Permits use of evidence if there is a causal link between the misconduct and the discovery of the evidence
Invoked this exception in upholding the admission of challenged evidence
Wong Sun v US
Segura v US
Brown v IL (5th amendment)
Determine whether the subsequent lawful acquisition of evidence was sufficiently attenuated from the initial misconduct
The temporal proximity between the two acts
The presences of intervening circumstances
The purpose and flagrancy of the official misconduct
3/26/25
Fourth Amendment
“Right of the people”
Introduces pre-existing right
Secure in their persons, houses, papers, and effects
Persons – privacy
Can’t have things taken without your consent
Secure
Covers property and privacy
Against unreasonable searches and seizures
Probable cause standard: greater than 50%
More likely than not
Question on intrusiveness of the search
Breathlizer = fine
Blood test = not fine
Individual right – don’t have cart blanche to search everything
Place to be searched must be written
Can’t have general warrant
Probable cause is connected with place and person to be searched
Exclusionary rule: any evidence found while violating the fourth amendment cannot be used in court
To enforce the fourth amendment we make the government (police) jump through hoops
Process protects the underlying right
Civil liberties end: individuals expectation of privacy protects police search or seizure
Conservative end: government has social welfare interest to search individuals
General Legal Standards
Warrant requirement with exceptions versus reasonableness standards
Place of search vs expectation of privacy
Does fourth amendment protect gov intrusion of property of privacy
Or both?
Exceptions to the warrant requirement
Incident to arrest
Loss of evidence
Consent searches
Safety searches
Plain view
Exigent circumstances
What’s search or seizure
Property interest only?
Olmstead (1928) – electronic surveillance not a physical invasion
Eavesdropping is fine
Going through the door would be unconstitutional
Katz v US (1967)
Why it would be constitutional: making yourself available to the public
Watching movements aren’t private behavior, anyone could observe the movements
Overturn the physical trespass doctrine
Even if space is temporarily occupied it’s still considered to be that person’s property
Reasonable expectation of privacy
Fourth amendment protections people, not places
As expectation of privacy increases, the level of scrutiny increases
Home is most obvious example of privacy
Capacity to claim the protection of the 4th depends not upon a property right in the invaded place but upon whether the area was on in which there was reasonable expectation of freedom from government intrusion
Low expectation of privacy
Times square
Very public place with many people
Open fields
Jails, prisons
Garbage
Public schools
Kyllo v US (2001)
Agent believes kyllo is growing weed
Uses thermal imaging to find warm spots
Use this evidence for a warrant
Unique status of thermal imaging device: used from outside
Not available for public use
Government's argument: creating heat is not a search of your home, its emanating from your house, getting information about heat that’s escaping the house
Also getting information about what’s happening outside of the house
Special use device and a physical intrusion
Carpenter
Put gps device on a car to monitor its movement
Court says this is an unconstitutional search as there was no warrant
Terry v Ohio
Facts of the Case
Terry and two men observed by police as what they believed to be casing a job, a stick-up
Stopped and frisked the men
Found two weapons
Terry convicted for carrying concealed weapon
Question
Was the search and seizure of Terry and the other men in violation of the Fourth Amendment?
Conclusion
8-1 decision
Search was reasonable under 4th amendment
Weapons seized could be introduced as evidence
Focus narrowly on the facts of the case
Court found that the officer acted on more than a hunch
Reasonable man would have warranted in believing terry was armed
Search was limited in scope and designed to protect the officer’s safety incident to the investigation
Birchfield v. North Dakota
Facts of the Case
Drove into ditch in ND
Police believed him to be intoxicated
Failed field sobriety test and arrested, didn’t consent to chemical test
Charged with misdemeanor for refusing
Moved to dismiss the charge and claimed it violated fourth amendment
Free from unreasonable searches and seizures when there was no probable cause that would support a warrant for the test
Happened with two other men as well, though the third consented to a blood test
Question
In the absence of a warrant, may a state statute criminalize an individual’s refusal to submit to a blood alcohol test?
Conclusion
First Decision
The fourth amendment does not permit warrantless blood tests incident to arrest for drunk driving
Warrantless breath tests are fine as they do not have significant privacy concerns, something that is routinely exposed to the public, reveal a limited amount of information, and do not enhance any embarrassment beyond what the arrest itself causes
Blood tests have privacy concerns because they require piercing of the skin
Refusing to submit a breath test is designed to serve the government’s interest in preventing drunk driving
Second decisions
The fourth amendment permits warrantless breath tests incident to arrest for drunk driving
United States v. Leon
Facts of the Case
Exclusionary rule requires that evidence illegally seized must be excluded from criminal trials
Leon – target of police surveillance based on an anonymous tip
Police applied to a judge for a search warrant of leon’s home based on the evidence from their surveillance
Judge issued warrant and police found drugs
Judge concluded that the affidavit for the search warrant was insufficient and did not establish probable cause
Question
Is there a “good faith” exception to the exclusionary rule?
Conclusion
Yes
Evidence seized on the basis of a mistakenly issued search warrant could be introduced at trial
The exclusionary rule is not a right, but a remedy justified by its ability to deter illegal police conduct
Cost of exclusionary rule outweighed the benefits
Exclusionary rule is costly to society
Guilty defendants go unpunished and people lose respect for the law
Rule cannot deter police in a case like Leon where they act in good faith on a warrant issued by a judge
Mapp v. Ohio
Facts of the Case
Mapp convicted of possessing obscene materials after an illegal police search of her home for a fugitive
Appealed on freedom of expression
Question
Were the confiscated materials protected from seizure by the Fourth Amendment?
Conclusion
Ignored first amendment issue
Declared all evidence obtained by searches and seizures in violation of the fourth amendment is inadmissible in a state court
Court struggled to determine when to apply exclusionary rule
3/28/25
Prior to kyllo
Protects property over privacy
Olmstead: protects property not privacy because it doesn’t constitute a search
Device used wasn’t available to the public
Was a special use device (not common use)
Katz: fourth amendment protects people not places
Where you have reasonable expectation of privacy, protects against warrantless searches
US v Jones
Movements in your car have a reasonable expectation of privacy
Police have gone to far with monitoring
Search is unconstitutional as they don’t have warrant
Carpenter
Protects places and privacy interests
Arrested four people in robbery, one member gives phone numbers
Police uses numbers to look at phone history, without a warrant
Police is able to track movements
Supreme court has already rulled that there’s an expectation of privacy
Key difference is that the property belongs to a third party
Third-party doctrine
Not searching the individual’s property but a company’s property
Individual has voluntarily shared information with the company
Lower expectation of privacy
Government says not a search under the fourth amendment
Smith and miller are 3rd party doctrine cases
Carpenter voluntarily gave his cellsite location to company and government can use the information to investigate
Supreme court rules that government actions are in violation of the first amendment
Cellsite information has reasonable expectation of privacy
Third-party doctrine is not extended to this case
Would be concession that individual is voluntarily giving their information over
Still tracking people’s movements which has been ruled unconstitutional in jones
Basic issue of what’s a search that falls under the fourth amendment
Incident to arrest has discretion for a search (persona and immediate surroundings)
Terry V. Ohio
Stop and frisk
Police have temporary ability to stop you (in a stop) – need reasonable suspicion
Reasonable suspicion: 25%
Controversial as can lead to racial profiling
Reasonable suspicion inferred on race
Standards and processes are intended to protect civil liberties
Standard; stops and pat gowns
Can apply to police stopping a vehicle
When do stops become seizures
Reasonable perception standard (1970s and 80s)
Only if in view of all the circumstances surrounding the incident, a reasonable person would have believed that he would believed that he was not free to leave
Later cases viewed such seizures like arrests – fourth amendment protections operative
Individual interest: don’t want to be harassed
Right to not be harassed by police
Police officer in ohio, in civilian clothes, walking on street and sees two men outside of the store – looking somewhat suspicious
Police officer believed they were doing a stickup, did a pat down, found guns on the men and the men were charged because of the men
Fourth amendment applies to stop and frisk (is a search that falls under the fourth amendment)
Immediate circumstance is to help the police (more for safety)
Case of a justifiable warrantless search
Patdown isn’t as intrusive as a full search