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.”
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.
A Terry stop in the United States allows the police to briefly detain a person based on reasonable suspicion of involvement in criminal activity. Reasonable suspicion is a lower standard than probable cause which is needed for arrest. When police stop and search a pedestrian, this is commonly known as a stop and frisk. When police stop an automobile, this is known as a traffic stop. If the police stop a motor vehicle on minor infringements in order to investigate other suspected criminal activity, this is known as a pretextual stop. Additional rules apply to stops that occur on a bus.
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.
"Stop and identify" statutes are laws in several U.S. states that authorize police to lawfully order people whom they reasonably suspect of committing a crime to state their name. If there is not reasonable suspicion that a person has committed a crime, is committing a crime, or is about to commit a crime, the person is not required to identify himself or herself, even in these states.
Georgia v. Randolph, 547 U.S. 103 (2006), is a case in which the U.S. Supreme Court held that without a search warrant, police had no constitutional right to search a house where one resident consents to the search while another resident objects. The Court distinguished this case from the "co-occupant consent rule" established in United States v. Matlock, 415 U.S. 164 (1974), which permitted one resident to consent in absence of the co-occupant.
United States v. Montoya De Hernandez, 473 U.S. 531 (1985), was a U.S. Supreme Court case regarding the Fourth Amendment's border search exception and balloon swallowing.
Illinois v. Caballes, 543 U.S. 405 (2005), is a decision by the Supreme Court of the United States in which the Court held that the use of a drug-sniffing police dog during a routine traffic stop does not violate the Fourth Amendment to the U.S. Constitution, even if the initial infraction is unrelated to drug offenses.
Florida v. Bostick, 501 U.S. 429 (1991), was a United States Supreme Court case that overturned a per se rule imposed by the Florida Supreme Court that held consensual searches of passengers on buses were always unreasonable. The Court ruled that the fact that the search takes place on a bus is one factor in determining whether a suspect feels free to decline the search and walk away from the officers.
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.
Florida v. Royer, 460 U.S. 491 (1983), was a U.S. Supreme Court case dealing with issues involving the Fourth Amendment. Specifically, the case establishes a firm line in cases where police conduct search and seizure without a warrant. The court ruled that, while it is legal for authorities to target and approach a person based on their behavior, absent more, they cannot detain or search such individual without a warrant.
Minnesota v. Dickerson, 508 U.S. 366 (1993), was a decision by the Supreme Court of the United States. The Court unanimously held that, when a police officer who is conducting a lawful patdown search for weapons feels something that plainly is contraband, the object may be seized even though it is not a weapon. By a 6-to-3 vote, however, the court held that the officer in this case had gone beyond the limits of a lawful patdown search before he could determine that the object was contraband, making the search and the subsequent seizure unlawful under the Fourth Amendment.
United States v. Brignoni-Ponce, 422 U.S. 873 (1975), was a case in which the Supreme Court determined it was a violation of the Fourth Amendment for a roving patrol car to stop a vehicle solely on the basis of the driver appearing to be of Mexican descent. A roving patrol car must have articulable facts that allow for an officer to have a reasonable suspicion that the person is carrying illegal aliens beyond their ethnicity. The Court handed down a 9–0 decision that affirmed the Circuit Court's ruling in the case.
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.
Whren v. United States, 517 U.S. 806 (1996), was a unanimous United States Supreme Court decision that "declared that any traffic offense committed by a driver was a legitimate legal basis for a stop."
Maryland v. Buie, 494 U.S. 325 (1990), was a decision by the Supreme Court of the United States handed down in 1990. In the case, the Court held that the Fourth Amendment permits a properly limited protective sweep in conjunction with an in-home arrest when the searching officer possesses a reasonable belief based on specific and articulable facts that the area to be swept harbors an individual posing a danger to those on the arrest scene.
Immigration and Naturalization Service v. Delgado, 466 U.S. 210 (1984), was a United States Supreme Court decision on the limits of worksite enforcement by immigration agents. Specifically, the Court ruled that factory raids by the Immigration and Naturalization Service (INS) were not illegal seizures under the Fourth Amendment to the U.S. Constitution.
Florida v. Jardines, 569 U.S. 1 (2013), was a United States Supreme Court case which resulted in the decision that police use of a trained detection dog to sniff for narcotics on the front porch of a private home is a "search" within the meaning of the Fourth Amendment to the United States Constitution, and therefore, without consent, requires both probable cause and a search warrant.
United States v. Drayton, 536 U.S. 194 (2002), was a case in which the United States Supreme Court clarified the applicability of Fourth Amendment protections to searches and seizures that occur on buses, as well as the function of consent during searches by law enforcement. During a scheduled stop in Tallahassee, Florida, police officers boarded a Greyhound bus as part of a drug interdiction effort and interviewed passengers. After talking to two of the passengers and asking if they could "check [their] person", officers discovered the two passengers had taped several packages of cocaine to their legs. At trial, the passengers argued that officers violated their Fourth Amendment rights against unreasonable searches and seizures because the police engaged in coercive behavior and never informed them that their participation in the drug interdiction efforts was voluntary.
