What Constitutes a Search Under the Fourth Amendment?
A "search" under the Fourth Amendment occurs when the government intrudes upon an individual's reasonable expectation of privacy. The Fourth Amendment protects individuals from unreasonable searches and seizures, and it generally requires that law enforcement have probable cause and a warrant to conduct a search, unless an exception to the warrant requirement applies.
Key Test for Determining a "Search"
The Supreme Court established a key test for determining when a search occurs in the landmark case of Katz v. United States, 389 U.S. 347 (1967). The ruling introduced a two-part test to determine if a government action qualifies as a "search":
Subjective Expectation of Privacy:
The individual must have a personal, subjective expectation that the place or activity in question is private. In other words, the person must behave in a way that indicates they seek privacy.Objective Expectation of Privacy:
The individual's expectation of privacy must be one that society recognizes as reasonable. This is an objective standard based on what society generally agrees upon as a legitimate expectation of privacy.
If both parts of this test are met, and the government intrudes upon that expectation, a search has occurred, and the protections of the Fourth Amendment apply.
Case Example: Katz v. United States
In Katz v. United States, the Supreme Court significantly expanded the understanding of what constitutes a search. In this case:
The government used an electronic listening device attached to the outside of a public phone booth to record Charles Katz’s conversations about illegal betting activities.
Katz argued that his Fourth Amendment rights were violated because he had a reasonable expectation of privacy in the phone booth, even though it was a public space.
The Supreme Court agreed with Katz, ruling that the Fourth Amendment protects people, not places. Even though Katz was in a public phone booth, by entering the booth and closing the door, he demonstrated a subjective expectation of privacy, and society would recognize that expectation as reasonable. The government's use of the recording device without a warrant violated Katz’s reasonable expectation of privacy, thus constituting a search.
Key Points from Katz:
No Physical Trespass Required:
The Court rejected the idea that a "search" only occurs when there is a physical intrusion into a constitutionally protected area (such as a home or vehicle). In Katz, the government’s use of electronic surveillance, without physically entering the booth, still qualified as a search.Privacy vs. Location:
The Fourth Amendment is not limited to protecting specific places but instead protects personal privacy. This means that even actions in public places can be protected if the individual has a reasonable expectation of privacy (e.g., using a phone booth or an enclosed restroom).Expanding the Fourth Amendment:
Katz expanded the scope of the Fourth Amendment beyond tangible property and physical spaces, extending protections to communications and intangible interests, such as telephone conversations.
Examples of When a "Search" Occurs
Searching a Home or Vehicle:
The search of a home, apartment, or vehicle is almost always considered a Fourth Amendment search, as these are places where individuals have a reasonable expectation of privacy. Law enforcement must typically obtain a warrant to search these areas unless an exception (such as exigent circumstances or consent) applies.Electronic Surveillance:
As established in Katz, using electronic surveillance (such as wiretaps or recording devices) to monitor a person's conversations or activities may constitute a search if the individual has a reasonable expectation of privacy in the place or conversation being monitored.Search of Personal Belongings:
Law enforcement searching personal belongings, such as purses, backpacks, or cell phones, generally requires a warrant or an applicable exception, as these are items where individuals typically have a reasonable expectation of privacy.Searching Through Trash:
In California v. Greenwood, 486 U.S. 35 (1988), the Supreme Court held that the Fourth Amendment does not protect trash left on the curb for collection because the individual no longer has a reasonable expectation of privacy once the trash is exposed to the public.
Examples of When a "Search" Does Not Occur
Plain View Doctrine:
If law enforcement is in a lawful position and observes evidence of a crime in plain view, no search has occurred. For example, if an officer legally enters a home and sees illegal drugs on a table, they can seize the drugs without a warrant under the plain view doctrine.Abandoned Property:
Once an individual abandons property, they no longer have an expectation of privacy in that property. For example, if someone discards an item in a public park or leaves a bag unattended in a public space, law enforcement may search it without a warrant.Open Fields Doctrine:
The open fields doctrine allows law enforcement to search land or areas outside the immediate curtilage of a home (the area directly surrounding a home) without a warrant. Courts have ruled that individuals do not have a reasonable expectation of privacy in open fields, even if the land is privately owned.
Additional Clarifications on What Constitutes a Search
Thermal Imaging Devices:
In Kyllo v. United States, 533 U.S. 27 (2001), the Supreme Court held that using thermal imaging devices to detect heat patterns inside a home, without physically entering the home, constitutes a search because individuals have a reasonable expectation of privacy regarding the heat emanating from their homes.GPS Tracking:
In United States v. Jones, 565 U.S. 400 (2012), the Court held that attaching a GPS tracking device to a vehicle without a warrant constitutes a search, as it is a physical intrusion that violates the reasonable expectation of privacy.Dog Sniffs:
The Supreme Court has ruled in Illinois v. Caballes, 543 U.S. 405 (2005), that a dog sniff conducted during a lawful traffic stop does not constitute a search if it only reveals the presence of illegal contraband and does not intrude on a legitimate expectation of privacy.
Conclusion: When Does a Search Occur?
A "search" for Fourth Amendment purposes occurs when the government intrudes upon an individual's reasonable expectation of privacy. This includes both physical searches and surveillance methods that do not involve physical intrusion, such as wiretapping or the use of electronic devices. The protections of the Fourth Amendment apply whenever a search invades privacy that society deems reasonable, as established by the two-part test from Katz v. United States.
Frequently Asked Questions (FAQs)
Does the Fourth Amendment only protect private property?
No, the Fourth Amendment protects people, not places. It applies whenever a person has a reasonable expectation of privacy, even if they are in a public space, as seen in Katz v. United States.Can the police search my phone without a warrant?
Generally, no. The Supreme Court has ruled in Riley v. California that police need a warrant to search the contents of a cell phone, as individuals have a reasonable expectation of privacy in their digital data.Does using a hidden camera to record someone count as a search?
If the hidden camera records someone in a place where they have a reasonable expectation of privacy (such as their home), it likely constitutes a search under the Fourth Amendment.Is using a drug-sniffing dog considered a search?
A drug-sniffing dog may not be considered a search if it only reveals the presence of contraband during a lawful stop. However, using a dog to search the curtilage of a home (the area immediately surrounding it) without a warrant is considered a search, as ruled in Florida v. Jardines.What is the plain view doctrine?
The plain view doctrine allows law enforcement to seize evidence without a warrant if it is immediately apparent and visible during a lawful observation.