The Fourth Amendment to the United States Constitution is part of the Bill of Rights. It prohibits unreasonable searches and seizures and 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 legal standard by which police authorities have reason to obtain a warrant for the arrest of a suspected criminal and for a court's issuing of a search warrant. One definition of the standard derives from the U.S. Supreme Court decision in the case of Beck v. Ohio (1964), that probable cause exists when “whether at [the moment of arrest] the facts and circumstances within [the] knowledge [of the police], and of which they had reasonably trustworthy information, [are] sufficient to warrant a prudent [person] in believing that [a suspect] had committed or was committing an offense.”
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. Place, 462 U.S. 696 (1983), is a decision by the Supreme Court of the United States in which the Court held that it does not violate the Fourth Amendment to the U.S. Constitution for a trained police dog to sniff of a person's luggage or property in a public place.
California v. Greenwood, 486 U.S. 35 (1988), was a case in which the Supreme Court of the United States held that the Fourth Amendment does not prohibit the warrantless search and seizure of garbage left for collection outside the curtilage of a home.
Maryland v. Garrison, 480 U.S. 79 (1987), is a United States Supreme Court case dealing with the Fourth Amendment of the United States Constitution and the extent of discretion given to police officers acting in good faith. The Court held that where police reasonably believe their warrant was valid during a search, execution of the warrant does not violate respondent's Fourth Amendment rights.
Illinois v. Rodriguez, 497 U.S. 177 (1990), is a U.S. Supreme Court case dealing with the issue of whether a warrantless search conducted pursuant to third party consent violates the Fourth Amendment when the third party does not actually possess common authority over the premises.
Samson v. California, 547 U.S. 843 (2006), is a United States Supreme Court case in which the Court affirmed the California Court of Appeal's ruling that suspicionless searches of parolees are lawful under California law and that the search in this case was reasonable under the Fourth Amendment to the United States Constitution because it was not arbitrary, capricious, or harassing.
Search incident to a lawful arrest, commonly known as search incident to arrest (SITA) or the Chimel rule, is a U.S. 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 preservation of evidence.
Arizona v. Hicks, 480 U.S. 321 (1987), held that the Fourth Amendment requires the police to have probable cause to seize items in plain view.
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.
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.
Wilson v. Arkansas, 514 U.S. 927 (1995), is a United States Supreme Court decision in which the Court held that the traditional, common-law-derived "knock and announce" rule for executing search warrants must be incorporated into the "reasonableness" analysis of whether the actual execution of the warrant is/was justified under the 4th Amendment. The high court thus ruled that the old "knock and announce" rule while not a hard requirement, was also not a dead letter.
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.
In United States Constitutional Law, a minimally intrusive/invasive warrantless search is a type of search that does not breach the boundaries of the property and is performed without any prerequisite search warrant. These searches are contested regularly in courts, and have been ruled for and against under different circumstances. The primary debate concerns the method in which the search is conducted, and also the area being searched. Issues concerning warrantless search and subsequent seizure are always of local concern, because they are a community law enforcement issue as well as a national law issue.
Camara v. Municipal Court, 387 U.S. 523 (1967), is a United States Supreme Court case that overruled a previous case and established the ability of a resident to deny entry to a building inspector without a warrant.
Birchfield v. North Dakota, 579 U.S. 438 (2016) is 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.
Griffin v. Wisconsin, 483 U.S. 868 (1987), was a case decided by the Supreme Court of the United States on June 26, 1987. The court decided that the warrantless search of a probationer's residence based on "reasonable grounds" in accordance with a state probation regulation did not violate the Fourth Amendment.
