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 United States criminal law, probable cause is the standard by which police authorities have reason to obtain a warrant for the arrest of a suspected criminal or the issuing of a search warrant. It is also the standard by which grand juries issue criminal indictments. The principle behind the standard is to limit the power of authorities to perform random or abusive searches, and to promote lawful evidence gathering and procedural form during criminal arrest and prosecution. The standard also applies to personal or property searches.
Search and Seizure is a procedure used in many civil law and common law legal systems by which police or other authorities and their agents, who, suspecting that a crime has been committed, commence a search of a person's property and confiscate any relevant evidence found in connection to the crime.
New Jersey v. T.L.O., 469 U.S. 325 (1985), is a decision by the Supreme Court of the United States addressing the constitutionality of a search of a public high school student for contraband after she was caught smoking. A subsequent search of her purse revealed drug paraphernalia, marijuana, and documentation of drug sales. She was charged as a juvenile for the drugs and paraphernalia found in the search. She fought the search, claiming it violated her Fourth Amendment right against unreasonable searches. The U.S. Supreme Court, in a 6–3 ruling, held that the search by the Piscataway Township Schools was reasonable under the Fourth Amendment.
Weeks v. United States, 232 U.S. 383 (1914), was a United States Supreme Court case in which the Court unanimously held that the warrantless seizure of items from a private residence constitutes a violation of the Fourth Amendment. It also prevented local officers from securing evidence by means prohibited under the federal exclusionary rule and giving it to their federal colleagues. It was not until the case of Mapp v. Ohio, 367 U.S. 643 (1961), that the exclusionary rule was deemed to apply to state courts as well.
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 Aguilar–Spinelli test was a judicial guideline set down by the U.S. Supreme Court for evaluating the validity of a search warrant or a warrantless arrest based on information provided by a confidential informant or an anonymous tip. The Supreme Court abandoned the Aguilar–Spinelli test in Illinois v. Gates, 462 U.S. 213 (1983), in favor of a rule that evaluates the reliability of the information under the "totality of the circumstances." However, Alaska, Hawaii, Massachusetts, New York, Vermont, Oregon, and Washington have retained the Aguilar–Spinelli test, based on their own state constitutions.
Brigham City v. Stuart, 547 U.S. 398 (2006), is a United States Supreme Court case involving the exigent circumstances exception to the Fourth Amendment's warrant requirement. The Court ruled that police may enter a home without a warrant if they have an objectively reasonable basis for believing that an occupant is or is about to be seriously injured.
Search incident to a lawful arrest, commonly known as search incident to arrest (SITA) or the Chimel rule, is a legal principle that allows police to perform a warrantless search of an arrested person, and the area within the arrestee’s immediate control, in the interest of officer safety, the prevention of escape, and the destruction of evidence.
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. The doctrine is not regarded as an exception to the Fourth Amendment, but rather to its requirement for a warrant or probable cause. Balanced against the sovereign's interests at the border are the Fourth Amendment rights of entrants. Not only is the expectation of privacy less at the border than in the interior, the Fourth Amendment balance between the interests of the government and the privacy right of the individual is also struck much more favorably to the government at the border. This balance at international borders means that routine searches are "reasonable" there, and therefore do not violate the Fourth Amendment's proscription against "unreasonable searches and seizures".
Welsh v. Wisconsin, 466 U.S. 740 (1984), was a 1983 case before the US Supreme Court determining whether a warrantless arrest violates the Fourth Amendment protection against unlawful search and seizure.
California v. Acevedo, 500 U.S. 565 (1991), was a decision of the United States Supreme Court, which interpreted the Carroll doctrine to provide one rule to govern all automobile searches. The Court stated, "The police may search an automobile and the containers within it where they have probable cause to believe contraband or evidence is contained." The decision also overruled the distinctions in United States v. Chadwick (1977) and Arkansas v. Sanders (1979) which had previously held that, if probable cause existed to search an automobile, the police may perform a warrantless search of the automobile and the containers within it, but if the police only had probable cause to search a container in the automobile, the police first had to obtain a warrant before searching the container.
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 warrantless search.
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 warrantless 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 United States Supreme Court which held that warrantless searches conducted in police-created exigent circumstances do not violate the Fourth Amendment so long as the police did not create the exigency by violating or threatening to violate the Fourth Amendment.
Steagald v. United States, 451 U.S. 204 (1981), is a United States Supreme Court case which held that, based on the Fourth Amendment, a police officer may not conduct a warrantless search of a third party's home in an attempt to apprehend the subject of an arrest warrant, absent consent or exigent circumstances.
Birchfield v. North Dakota, 579 U.S. ___ (2016), was a case in which the Supreme Court of the United States held that the search incident to arrest doctrine permits law enforcement to conduct warrantless breath tests but not blood tests on suspected drunk drivers.
Collins v. Virginia, No. 16-1027, 584 U.S. ___ (2018), was a case before the Supreme Court of the United States involving search and seizure. At issue was whether the Fourth Amendment's automobile 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 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 curtilage of a private homeowner.
