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 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. There is no universally accepted definition or formulation for probable cause. One traditional definition, which comes from the U.S. Supreme Court's 1964 decision Beck v. Ohio, is when "whether at [the moment of arrest] the facts and circumstances within [an officer's] knowledge 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."
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.
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.
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.
United States v. Arvizu, 534 U.S. 266 (2002), is a case in which the Supreme Court of the United States unanimously reaffirmed the proposition that the Fourth Amendment required courts to analyze the reasonableness of a traffic stop based on the totality of the circumstances instead of examining the plausibility of each reason an officer gives for stopping a motorist individually.
South Dakota v. Opperman, 428 U.S. 364 (1976), elaborated on the community caretaking doctrine. Under the Fourth Amendment, "unreasonable" searches and seizures are forbidden. In addition to their law-enforcement duties, the police must engage in what the court has termed a community caretaking role, including such duties as removing obstructions from roadways to ensure the free flow of traffic. When the police act in this role, they may inventory cars they have seized without "unreasonably" searching those cars.
Knowles v. Iowa, 525 U.S. 113 (1998), was a decision by the United States Supreme Court which ruled that the Fourth Amendment prohibits a police officer from further searching a vehicle which was stopped for a minor traffic offense once the officer has written a citation for the offense.
Ohio v. Robinette, 519 U.S. 33 (1996), was a United States Supreme Court case in which the Court held that the Fourth Amendment does not require police officers to inform a motorist at the end of a traffic stop that they are free to go before seeking permission to search the motorist's car.
Florida v. Rodriguez, 469 U.S. 1 (1984), was a United States Supreme Court case concerning the Fourth Amendment rights of protection from search and seizure. The case involved defendant Damasco Vincente Rodriguez against the State of Florida. After the Florida State Court and the District Court of Appeal of Florida both judged in favor of the defendant, the State of Florida appealed for a writ of Certiorari. The Supreme Court sided with the State of Florida, overturning the decision of the Florida state courts.
Maryland v. Pringle, 540 U.S. 366 (2003), was a decision by the Supreme Court of the United States in which the Court unanimously upheld the arrest of three passengers in an automobile where drugs were found. The case regards the reasonableness of the arrest of a passenger in an automobile.
Pearson v. Callahan, 555 U.S. 223 (2009), was a case decided by the United States Supreme Court dealing with the doctrine of qualified immunity.
United States v. Mendenhall, 446 U.S. 544 (1980), was a United States Supreme Court case that determined "seizure" occurs when an officer uses displays of authority to detain a person.
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.
Florida v. Jimeno, 500 U.S. 248 (1991), was a U.S. Supreme Court case involving the exclusionary rule of evidence under the Fourth Amendment.
Fernandez v. California, 571 U.S. 292 (2014), was a U.S. Supreme Court case that explored the limits of Georgia v. Randolph, a 2006 case that held that consent to search a dwelling is invalid in the presence of an objecting co-resident. Fernandez, however, held that when the objecting co-resident is removed for objectively reasonable purposes, the remaining resident may validly consent to search.
Rodriguez v. United States, 575 U.S. 348 (2015), was a United States Supreme Court case which analyzed whether police officers may extend the length of a traffic stop to conduct a search with a trained detection dog. In a 6–3 opinion, the Court held that officers may not extend the length of a traffic stop to conduct a dog sniff unrelated to the original purpose of the stop. However, the Court remanded the case to the United States Court of Appeals for the Eighth Circuit to determine whether the officer's extension of the traffic stop was independently justified by reasonable suspicion. Some analysts have suggested that the Court's decision to limit police authority was influenced by ongoing protests in Ferguson, Missouri.
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.
United States v. Sharpe, 470 U.S. 675 (1985), was a legal case in which the Supreme Court of the United States clarified how long police are permitted to stop vehicles as part of an investigatory stop before it violates the Fourth Amendment to the U.S. Constitution.
