The Fourth Amendment to the United States Constitution is part of the Bill of Rights. It prohibits unreasonable searches and seizures. In addition, it sets requirements for issuing warrants: warrants must be issued by a judge or magistrate, justified by probable cause, supported by oath or affirmation, and must particularly describe the place to be searched and the persons or things to be seized.
In criminal procedure law of the United States, an exigent circumstance allows law enforcement to enter a structure without a search warrant, or if they have a "knock and announce" warrant, allows them to enter without knocking and waiting for the owner's permission to enter. It must be a situation where people are in imminent danger, evidence faces imminent destruction, or a suspect's escape is imminent. Once entry is obtained, the plain view doctrine applies, allowing the seizure of any evidence or contraband discovered in the course of actions consequent upon the exigent circumstances.
United States v. Ross, 456 U.S. 798 (1982), was a search and seizure case argued before the Supreme Court of the United States. The high court was asked to decide if a legal warrantless search of an automobile allows closed containers found in the vehicle to be searched as well. The appeals court had previously ruled that opening and searching the closed portable containers without a warrant was a violation of the Fourth Amendment, even though the warrantless vehicle search was permissible due to existing precedent.
The motor vehicle exception is a legal rule in the United States that modifies the normal probable cause requirement of the Fourth Amendment to the United States Constitution and, when applicable, allows a police officer to search a motor vehicle without a search warrant.
Ker v. California, 374 U.S. 23 (1963), was a case before the United States Supreme Court, which incorporated the Fourth Amendment's protections against illegal search and seizure. The case was decided on June 10, 1963, by a vote of 5–4.
In United States criminal law, the border search exception is a doctrine that allows searches and seizures at international borders and their functional equivalent without a warrant or probable cause. Generally speaking, searches within 100 miles of the border are more permissible without a warrant than those conducted elsewhere in the U.S. The doctrine also allows federal agents to search people at border crossings without a warrant or probable cause. The government is allowed to use scanning devices and to search personal electronics. Invasive bodily searches, however, require reasonable suspicion.
Carroll v. United States, 267 U.S. 132 (1925), was a decision by the United States Supreme Court that upheld the warrantless searches of an automobile, which is known as the automobile exception. The case has also been cited as widening the scope of search.
United States v. Chadwick, 433 U.S. 1 (1977), was a decision by the United States Supreme Court, which held that, absent exigency, the warrantless search of double-locked luggage just placed in the trunk of a parked vehicle is a violation of the Fourth Amendment and not justified under the automobile exception. The Court reasoned that while luggage is movable like an automobile, it does not have the lesser expectation of privacy associated with an automobile.
Arkansas v. Sanders, 442 U.S. 753 (1979), was a decision by the United States Supreme Court, which held that absent exigency, the warrantless search of personal luggage merely because it was located in an automobile lawfully stopped by the police, is a violation of the Fourth Amendment and not justified under the automobile exception. Similar to United States v. Chadwick (1977), the luggage was the subject of police suspicion before being placed in the vehicle.
Wyoming v. Houghton, 526 U.S. 295 (1999), is a United States Supreme Court case which held that absent exigency, the warrantless search of a passenger's container capable of holding the object of a search for which there is probable cause is not a violation of the Fourth Amendment to the United States Constitution because it is justified under the automobile exception as an effect of the car.
Arizona v. Gant, 556 U.S. 332 (2009), was a United States Supreme Court decision holding that the Fourth Amendment to the United States Constitution requires law-enforcement officers to demonstrate an actual and continuing threat to their safety posed by an arrestee, or a need to preserve evidence related to the crime of arrest from tampering by the arrestee, in order to justify a warrantless vehicular search incident to arrest conducted after the vehicle's recent occupants have been arrested and secured.
New York v. Belton, 453 U.S. 454 (1981), was a United States Supreme Court case in which the Court held that when a police officer has made a lawful custodial arrest of the occupant of an automobile, the officer may, as a contemporaneous incident of that arrest, search the passenger compartment of that automobile. Therefore, Belton extended the so-called "Chimel rule" of searches incident to a lawful arrest, established in Chimel v. California (1969), to vehicles. The Supreme Court sought to establish bright line rules to govern vehicle search incident to eliminate some confusion in the cases.
Chambers v. Maroney, 399 U.S. 42 (1970), was a United States Supreme Court case in which the Court applied the Carroll doctrine in a case with a significant factual difference—the search took place after the vehicle was moved to the stationhouse. The search was thus delayed and did not take place on the highway as in Carroll. After a gas station robbery, a vehicle fitting the description of the robbers' car was stopped. Inside were people wearing clothing matching the description of that worn by the robbers. They were arrested, and the car was taken to the police station where it was later searched.
Almeida-Sanchez v. United States, 413 U.S. 266 (1973), was a United States Supreme Court case holding that the search of an automobile by the United States Border Patrol without a warrant or probable cause violates the Fourth Amendment. The vehicle was stopped and searched for illegal aliens twenty-five miles (40 km) from the Mexican border. The Court approached the search from four views: automobile search, administrative inspection, heavily regulated industry inspection, and border search. As to the validity of the search under the automobile exception, the Court found no justification for the search under the Carroll doctrine because there was no probable cause. As to the validity of the search under various administrative inspection doctrines, the Court found that the officers lacked an area warrant. As to the validity of the heavily regulated industry inspection, the Court found that the doctrine is not applicable to traveling on a state highway. As to the validity of a border search, the Court found that the site of the stop and the entirety of the road on which the stop occurred was too far from the border to be considered a border search.
Kentucky v. King, 563 U.S. 452 (2011), was a decision by the US Supreme Court, which held that warrantless searches conducted in police-created exigent circumstances do not violate the Fourth Amendment as long as the police did not create the exigency by violating or threatening to violate the Fourth Amendment.
United States v. Jones, 565 U.S. 400 (2012), was a landmark United States Supreme Court case in which the court held that installing a Global Positioning System (GPS) tracking device on a vehicle and using the device to monitor the vehicle's movements constitutes a search under the Fourth Amendment.
County of Riverside v. McLaughlin, 500 U.S. 44 (1991), was a United States Supreme Court case which involved the question of within what period of time must a suspect arrested without a warrant be brought into court to determine if there is probable cause for holding the suspect in custody. The majority held that suspects must generally be granted a probable cause determination within 48 hours of arrest. The dissent believed that probable cause hearings should generally be provided much sooner, as soon as the police complete the administrative steps incident to arrest.
United States v. Watson, 423 U.S. 411 (1976), was a case decided by the Supreme Court of the United States that decided that a warrantless arrest in public and consenting to a vehicle search did not violate the Fourth Amendment.
Collins v. Virginia, No. 16-1027, 584 U.S. ___ (2018), was a case before the US Supreme Court involving search and seizure. At issue was whether the Fourth Amendment's motor vehicle exception permits a police officer uninvited and without a warrant to enter private property, approach a house, and search a vehicle parked a few feet from the house that is otherwise visible from off the property. In an 8–1 judgement, the Supreme Court ruled that the automobile exception does not apply to vehicles parked within the home or the curtilage of a private homeowner.
Johnson v. United States, 333 U.S. 10 (1948), was a significant United States Supreme Court decision addressing search warrants and the Fourth Amendment. In this case, where federal agents had probable cause to search a hotel room but did not obtain a warrant, the Court declared the search was "unreasonable."
