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.
Mapp v. Ohio, 367 U.S. 643 (1961), was a landmark decision of the U.S. Supreme Court in which the Court ruled that the exclusionary rule, which prevents prosecutors from using evidence in court that was obtained by violating the Fourth Amendment to the U.S. Constitution, applies not only to the federal government but also to the U.S. state governments. The Supreme Court accomplished this by use of a principle known as selective incorporation; in Mapp this involved the incorporation of the provisions, as interpreted by the Court, of the Fourth Amendment which is applicable only to actions of the federal government into the Fourteenth Amendment's due process clause which is applicable to actions of the states.
In the United States, the exclusionary rule is a legal rule, based on constitutional law, that prevents evidence collected or analyzed in violation of the defendant's constitutional rights from being used in a court of law. This may be considered an example of a prophylactic rule formulated by the judiciary in order to protect a constitutional right. The exclusionary rule may also, in some circumstances at least, be considered to follow directly from the constitutional language, such as the Fifth Amendment's command that no person "shall be compelled in any criminal case to be a witness against himself" and that no person "shall be deprived of life, liberty or property without due process of law."
The open-fields doctrine, in the U.S. law of criminal procedure, is the legal doctrine that a "warrantless search of the area outside a property owner's curtilage" does not violate the Fourth Amendment to the United States Constitution. However, "unless there is some other legal basis for the search," such a search "must exclude the home and any adjoining land that is within an enclosure or otherwise protected from public scrutiny."
Stanley v. Georgia, 394 U.S. 557 (1969), was a U.S. Supreme Court decision that helped to establish an implied "right to privacy" in U.S. law in the form of mere possession of obscene materials.
Olmstead v. United States, 277 U.S. 438 (1928), was a decision of the Supreme Court of the United States, on the matter of whether wiretapping of private telephone conversations, obtained by federal agents without a search warrant and subsequently used as evidence, constituted a violation of the target’s rights under the Fourth and Fifth Amendments. In a 5–4 decision, the Court held that the Constitutional rights of a wiretapping target have not been violated. This decision was overturned by Katz v. United States in 1967.
In United States law, 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.
In common law, the fleeing felon rule permits the use of force, including deadly force, against an individual who is suspected of a felony and is in clear flight.
Chimel v. California, 395 U.S. 752 (1969), was a 1969 United States Supreme Court case in which the Court held that police officers arresting a person at home could not search the entire home without a search warrant, but police may search the area within immediate reach of the person without a warrant. The rule on searches incident to a lawful arrest within the home is now known as the Chimel Rule.
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.
Hudson v. Michigan, 547 U.S. 586 (2006), is a United States Supreme Court case in which the Court held that a violation of the Fourth Amendment requirement that police officers knock, announce their presence, and wait a reasonable amount of time before entering a private residence does not require suppression of the evidence obtained in the ensuing search.
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.
Franks v. Delaware, 438 U.S. 154 (1978), is a United States Supreme Court case dealing with defendants' rights to challenge evidence collected on the basis of a warrant granted on the basis of a false statement. The court held that where a warrant affidavit contains a statement, necessary to the finding of probable cause, that is demonstrated to be both false and included by an affiant knowingly and intentionally, or with reckless disregard for the truth, the warrant is not valid.
Aguilar v. Texas, 378 U.S. 108 (1964), was a decision by the United States Supreme Court, which held that "[a]lthough an affidavit supporting a search warrant may be based on hearsay information and need not reflect the direct personal observations of the affiant, the magistrate must be informed of some of the underlying circumstances relied on by the person providing the information and some of the underlying circumstances from which the affiant concluded that the informant, whose identity was not disclosed, was credible or his information reliable." Along with Spinelli v. United States (1969), Aguilar established the Aguilar–Spinelli test, a judicial guideline for evaluating the validity of a search warrant based on information provided by a confidential informant or an anonymous tip. The test developed in this case was subsequently rejected and replaced in Illinois v. Gates, 462 U.S. 213 (1983).
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.
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.
In the law of the United States, the mere evidence rule was a historical doctrine that defined the scope of the Fourth Amendment to the United States Constitution.
People v. Diaz, 51 Cal. 4th 84, 244 P.3d 501, 119 Cal. Rptr. 3d 105 was a Supreme Court of California case, which held that police are not required to obtain a warrant to search information contained within a cell phone in a lawful arrest. In a sting operation conducted by local police, the defendant, Gregory Diaz, was arrested for the sale of the illicit drug ecstasy and his cellphone, containing incriminating evidence, was seized and searched without a warrant. In trial court proceedings, Diaz motioned to suppress the information obtained from his cellphone, which was denied on the grounds that the search of his cellphone was incident to a lawful arrest. The California Court of Appeal affirmed the court's decision and was later upheld by the California Supreme Court. In 2014, the United States Supreme Court overruled that position in Riley v. California and held that without a warrant, police may not search the digital information on a cellphone that has been seized incident to arrest.
Riley v. California, 573 U.S. 373 (2014), is a landmark United States Supreme Court case in which the court ruled that the warrantless search and seizure of the digital contents of a cell phone during an arrest is unconstitutional under the Fourth Amendment.
Stone v. Powell, 428 U.S. 465 (1976), was decision of the Supreme Court of the United States that limited which claims of Fourth Amendment violations could be made by state prisoners in habeas corpus petitions in federal courts. Specifically, a claim that the exclusionary rule had been broken would be barred if state courts had already given it a full and fair hearing. The decision combined two cases that were argued before the Supreme Court on the same day with similar issues, one filed by Lloyd Powell and the other, titled Wolff v. Rice, filed by David Rice.
