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."
Wolf v. Colorado, 338 U.S. 25 (1949), was a United States Supreme Court case in which the Court held 6-3 that, while the Fourth Amendment was applicable to the states, the exclusionary rule was not a necessary ingredient of the Fourth Amendment's right against warrantless and unreasonable searches and seizures. In Weeks v. United States, 232 U.S. 383 (1914), the Court held that as a matter of judicial implication the exclusionary rule was enforceable in federal courts but not derived from the explicit requirements of the Fourth Amendment. The Wolf Court decided not to incorporate the exclusionary rule as part of the Fourth Amendment in large part because the states which had rejected the Weeks Doctrine had not left the right to privacy without other means of protection. However, because most of the states' rules proved to be ineffective in deterrence, the Court overruled Wolf in Mapp v. Ohio, 367 U.S. 643 (1961). This landmark case made the exclusionary rule enforceable against the states through the Due Process clause of the Fourteenth Amendment to the same extent that it applied against the federal government.
Shaffer v. Heitner, 433 U.S. 186 (1977), is a United States corporate law case in which the Supreme Court of the United States established that a defendant's ownership of stock in a corporation incorporated within a state, without more, is insufficient to allow that state courts to exercise jurisdiction over the defendant. The case set forth a framework for evaluating when a defendant will be deemed to have minimum contacts with the forum state sufficient for the exercise of jurisdiction to be consistent with due process under the Fourteenth Amendment.
Katz v. United States, 389 U.S. 347 (1967), was a landmark decision of the U.S. Supreme Court in which the Court redefined what constitutes "searches" and "seizures" with regard to the protections of the Fourth Amendment to the U.S. Constitution. The decision expanded the Fourth Amendment's protections from the right of search and seizures of an individual's "persons, houses, papers, and effects", as defined in the Constitution, to include "what [a person] seeks to preserve as private, even in an area accessible to the public" as a constitutionally protected area. The case introduced the Katz test to determine a reasonable expectation of privacy, defined as a two-part test written in a concurrence by Justice John Marshall Harlan II. The Katz test has been used in thousands of cases, particularly with the advancement of technology that poses new questions on expectations of privacy.
In the United States, the plain view doctrine is an exception to the Fourth Amendment's warrant requirement that allows an officer to seize evidence and contraband that are found in plain view during a lawful observation. The doctrine is also regularly used by TSA officers while screening persons and property at U.S. airports.
Olmstead v. United States, 277 U.S. 438 (1928), was a decision of the Supreme Court of the United States, in which the Court reviewed whether the use of wiretapped private telephone conversations, obtained by federal agents without judicial approval and subsequently used as evidence, constituted a violation of the defendant’s rights provided by the Fourth and Fifth Amendments. In a 5–4 decision, the Court held that neither the Fourth Amendment nor the Fifth Amendment rights of the defendant were violated. This decision was later overturned by Katz v. United States in 1967.
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.
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. Dunn, 480 U.S. 294 (1987), is a U.S. Supreme Court decision relating to the open fields doctrine limiting the Fourth Amendment of the U.S. Constitution.
Skinner v. Railway Labor Executives Association, 489 U.S. 602 (1989), was the U.S. Supreme Court case that paved the way for random drug testing of public employees in "safety sensitive" positions.
Inevitable discovery is a doctrine in United States criminal procedure that permits admission of evidence that was obtained through illegal means if it would "inevitably" have been obtained regardless of the illegality. It is one of several exceptions to the exclusionary rule, or the related fruit-of-the-poisonous tree doctrine, which prevent evidence collected in violation of a defendant's constitutional rights from being admitted in court.
Ker v. Illinois, 119 U.S. 436 (1886), is a U.S. Supreme Court case. It held that a fugitive kidnapped from abroad could not claim any violation of the Constitution, laws or treaties of the United States.
United States v. Ortiz, 422 U.S. 891 (1975), was a United States Supreme Court case in which the Court held that the Fourth Amendment prevented Border Patrol officers from conducting warrantless, suspicionless searches of private vehicles removed from the border or its functional equivalent.
Bond v United States, 529 U.S. 334 (2000), was a United States Supreme Court Fourth Amendment case that applied the ruling of Minnesota v. Dickerson to luggage, which held that police may not physically manipulate items without a warrant without violating the Fourth Amendment.
United States v. White, 401 U.S. 745 (1971), was a United States Supreme Court decision which held that recording conversations using concealed radio transmitters worn by informants does not violate the Fourth Amendment protection against unreasonable searches and seizures, and thus does not require a warrant.
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."
United States v. Knotts, 460 U.S. 276 (1983), was a United States Supreme Court case regarding the use of an electronic surveillance device. The defendants argued that the use of this device was a Fourth Amendment violation. The device in question was described as a beeper that could only be tracked from a short distance. During a single trip, officers followed a car containing the beeper, relying on beeper signal to determine the car's final destination. The Court unanimously held that since the use of such a device did not violate a legitimate expectation of privacy there was no search and seizure and thus the use was allowed without a warrant. It reasoned that a person traveling in public has no expectation of privacy in one's movements. Since there was no search and seizure there was not a Fourth Amendment violation.
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.
Murray v. United States, 487 U.S. 533 (1988), was a United States Supreme Court decision that created the modern "independent source doctrine" exception to the exclusionary rule. The exclusionary rule makes most evidence gathered through violations of the Fourth Amendment to the United States Constitution inadmissible in criminal trials as "fruit of the poisonous tree". In Murray, the Court ruled that when officers conduct two searches, the first unlawful and the second lawful, evidence seized during the second search is admissible if the second search "is genuinely independent of [the] earlier one."
Johnson v. United States, 333 U.S. 10 (1948), was a significant United States Supreme Court decision addressing search warrants and the Fourth Amendment. In this case, where federal agents had probable cause to search a hotel room but did not obtain a warrant, the Court declared the search was "unreasonable."
