Established in Weeks v. United States , this rule holds that evidence obtained as a result of a Fourth Amendment violation is generally inadmissible at criminal trials. Evidence discovered as a later result of an illegal search may also be inadmissible as " fruit of the poisonous tree ", unless it inevitably would have been discovered by legal means.
The Fourth Amendment was adopted in response to the abuse of the writ of assistance , a type of general search warrant issued by the British government , and a major source of tension in pre-Revolutionary America. The Fourth Amendment was introduced in Congress in by James Madison , along with the other amendments in the Bill of Rights, in response to Anti-Federalist objections to the new Constitution.
Congress submitted the amendment to the states on September 28, By December 15, , the necessary three-fourths of the states had ratified it. Because the Bill of Rights did not initially apply to state or local governments, and federal criminal investigations were less common in the first century of the nation's history, there is little significant case law for the Fourth Amendment before the 20th century.
The amendment was held to apply to state and local governments in Mapp v. The right of the people to be secure in their persons, houses, papers, and effects, [a] against unreasonable searches and seizures, shall not be violated, and no Warrants shall issue, but upon probable cause, supported by Oath or affirmation, and particularly describing the place to be searched, and the persons or things to be seized.
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Like many other areas of American law, the Fourth Amendment finds its roots in English legal doctrine. In Semayne's case , Sir Edward Coke famously stated: "The house of every one is to him as his castle and fortress, as well for his defence against injury and violence as for his repose. The s saw a growth in the intensity of litigation against state officers, who, using general warrants, conducted raids in search of materials relating to John Wilkes 's publications attacking both government policies and the King himself.
The most famous of these cases involved John Entick , whose home was forcibly entered by the King's Messenger Nathan Carrington, along with others, pursuant to a warrant issued by George Montagu-Dunk, 2nd Earl of Halifax authorizing them "to make strict and diligent search for Charles Pratt, 1st Earl Camden ruled that both the search and the seizure were unlawful, as the warrant authorized the seizure of all of Entick's papers—not just the criminal ones—and as the warrant lacked probable cause to even justify the search.
By holding that "[O]ur law holds the property of every man so sacred, that no man can set his foot upon his neighbour's close without his leave",  Entick established the English precedent that the executive is limited in intruding on private property by common law. Homes in Colonial America , on the other hand, did not enjoy the same sanctity as their British counterparts, because legislation had been explicitly written so as to enable enforcement of British revenue-gathering policies on customs; until , in fact, the only type of warrant defined in the handbooks for justices of the peace was the general warrant.
In , the colony of Massachusetts barred the use of general warrants. This represented the first law in American history curtailing the use of seizure power.
Its creation largely stemmed from the great public outcry over the Excise Act of , which gave tax collectors unlimited powers to interrogate colonists concerning their use of goods subject to customs. All writs automatically expired six months after the death of the King, and would have had to be re-issued by George III , the new king, to remain valid.
In mid-January , a group of over 50 merchants represented by James Otis petitioned the court to have hearings on the issue. During the five-hour hearing on February 23, , Otis vehemently denounced British colonial policies, including their sanction of general warrants and writs of assistance.
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Because of the name he had made for himself in attacking the writs, Otis was elected to the Massachusetts colonial legislature and helped pass legislation requiring that special writs of assistance be "granted by any judge or justice of the peace upon information under oath by any officer of the customs" and barring all other writs. The governor overturned the legislation, finding it contrary to English law and parliamentary sovereignty. Seeing the danger general warrants presented, the Virginia Declaration of Rights explicitly forbade the use of general warrants.
This prohibition became a precedent for the Fourth Amendment: . That general warrants, whereby any officer or messenger may be commanded to search suspected places without evidence of a fact committed, or to seize any person or persons not named, or whose offense is not particularly described and supported by evidence, are grievous and oppressive and ought not to be granted. Article XIV of the Massachusetts Declaration of Rights, written by John Adams and enacted in as part of the Massachusetts Constitution, added the requirement that all searches must be "reasonable," and served as another basis for the language of the Fourth Amendment: .
Every subject has a right to be secure from all unreasonable searches, and seizures of his person, his houses, his papers, and all his possessions. All warrants, therefore, are contrary to this right, if the cause or foundation of them be not previously supported by oath or affirmation; and if the order in the warrant to a civil officer, to make search in suspected places, or to arrest one or more suspected persons, or to seize their property, be not accompanied with a special designation of the persons or objects of search, arrest, or seizure: and no warrant ought to be issued but in cases, and with the formalities, prescribed by the laws.
By , eight state constitutions contained a provision against general warrants. After several years of comparatively weak government under the Articles of Confederation , a Constitutional Convention in Philadelphia proposed a new constitution on September 17, , featuring a stronger chief executive and other changes. George Mason , a Constitutional Convention delegate and the drafter of Virginia's Declaration of Rights, proposed that a bill of rights listing and guaranteeing civil liberties be included. Other delegates—including future Bill of Rights drafter James Madison —disagreed, arguing that existing state guarantees of civil liberties were sufficient and that any attempt to enumerate individual rights risked the implication that other, unnamed rights were unprotected.
After a brief debate, Mason's proposal was defeated by a unanimous vote of the state delegations. For the constitution to be ratified, however, nine of the thirteen states were required to approve it in state conventions. Opposition to ratification "Anti-Federalism" was partly based on the Constitution's lack of adequate guarantees for civil liberties.
Supporters of the Constitution in states where popular sentiment was against ratification including Virginia, Massachusetts, and New York successfully proposed that their state conventions both ratify the Constitution and call for the addition of a bill of rights. In the 1st United States Congress , following the state legislatures' request, James Madison proposed twenty constitutional amendments based on state bills of rights and English sources such as the Bill of Rights , including an amendment requiring probable cause for government searches.
Congress reduced Madison's proposed twenty amendments to twelve, with modifications to Madison's language about searches and seizures. By the time the Bill of Rights was submitted to the states for ratification, opinions had shifted in both parties. Many Federalists, who had previously opposed a Bill of Rights, now supported the Bill as a means of silencing the Anti-Federalists' most effective criticism.
Many Anti-Federalists, in contrast, now opposed it, realizing that the Bill's adoption would greatly lessen the chances of a second constitutional convention, which they desired.
On November 20, , New Jersey ratified eleven of the twelve amendments, including the Fourth. On December 19, , December 22, , and January 19, , respectively, Maryland, North Carolina, and South Carolina ratified all twelve amendments. All three states would later ratify the Bill of Rights for sesquicentennial celebrations in Virginia initially postponed its debate, but after Vermont was admitted to the Union in , the total number of states needed for ratification rose to eleven. Vermont ratified on November 3, , approving all twelve amendments, and Virginia finally followed on December 15, The Bill of Rights originally only restricted the federal government , and went through a long initial phase of "judicial dormancy";  in the words of historian Gordon S.
Wood , "After ratification, most Americans promptly forgot about the first ten amendments to the Constitution. As federal criminal jurisdiction expanded to include other areas such as narcotics , more questions about the Fourth Amendment came to the Supreme Court. Supreme Court responded to these questions by outlining the fundamental purpose of the amendment as guaranteeing "the privacy, dignity and security of persons against certain arbitrary and invasive acts by officers of the Government, without regard to whether the government actor is investigating crime or performing another function".
Ohio ,  the U. Fourth Amendment case law deals with three central issues: what government activities constitute "search" and "seizure"; what constitutes probable cause for these actions; how violations of Fourth Amendment rights should be addressed. The Fourth Amendment typically requires "a neutral and detached authority interposed between the police and the public", and it is offended by "general warrants" and laws that allows searches to be conducted "indiscriminately and without regard to their connection with [a] crime under investigation",  for the "basic purpose of the Fourth Amendment, which is enforceable against the States through the Fourteenth, through its prohibition of 'unreasonable' searches and seizures is to safeguard the privacy and security of individuals against arbitrary invasions by governmental officials.
The Fourth Amendment has been held to mean that a search or an arrest generally requires a judicially sanctioned warrant , because the basic rule under the Fourth Amendment is that arrests and "searches conducted outside the judicial process, without prior approval by judge or magistrate, are per se unreasonable".
The Supreme Court further held in Chandler v. Miller : "To be reasonable under the Fourth Amendment, a search ordinarily must be based on individualized suspicion of wrongdoing. But particularized exceptions to the main rule are sometimes warranted based on 'special needs, beyond the normal need for law enforcement'. Quon , the Court applied the amendment to a municipal government in its capacity as an employer, ruling that the City of Ontario had not violated the Fourth Amendment rights of city police officers by obtaining from the communications company and reviewing transcripts of text messages sent using government-provided pagers.
One threshold question in the Fourth Amendment jurisprudence is whether a "search" has occurred. Initial Fourth Amendment case law hinged on a citizen's property rights —that is, when the government physically intrudes on "persons, houses, papers, or effects" for the purpose of obtaining information, a "search" within the original meaning of the Fourth Amendment has occurred. Early 20th-century Court decisions, such as Olmstead v.
United States , held that Fourth Amendment rights applied in cases of physical intrusion, but not to other forms of police surveillance e. United States , the Court stated of the amendment that "at the very core stands the right of a man to retreat into his own home and there be free from unreasonable governmental intrusion". Fourth Amendment protections expanded significantly with Katz v. United States While there was no physical intrusion into the booth, the Court reasoned that: 1 Katz, by entering the booth and shutting the door behind him, had exhibited his expectation that "the words he utters into the mouthpiece will not be broadcast to the world"; and 2 society believes that his expectation was reasonable.
Justice Potter Stewart wrote in the majority opinion that "the Fourth Amendment protects people, not places". This decision in Katz was later developed into the now commonly used two-prong test, adopted in Smith v. Maryland ,  for determining whether a search has occurred for purposes of the Fourth Amendment:  .
The Supreme Court has held that the Fourth Amendment does not apply to information that is voluntarily shared with third parties. United States , individuals have a reasonable expectation of privacy under the Fourth Amendment regarding cell phone records even though they themselves turned over that information to "third parties" i. Prior to the Carpenter ruling, law enforcement was able to retrieve cell site location information CSLI that included where a cell phone user had traveled over many months and with which other cell phone users they had associated.
Carpenter v. United Staes serves as a landmark case because it slightly narrowed the Third Party Doctrine, thus requiring law enforcement to first obtain a search warrant before receiving CSLI records. Following Katz , the vast majority of Fourth Amendment search cases have turned on the right to privacy, but in United States v. Jones , the Court ruled that the Katz standard did not replace earlier case law, but rather, has supplemented it. The Court concluded that Jones was a bailee to the car, and so had a property interest in the car. The Court used similar "trespass" reasoning in Florida v.
Jardines , to rule that bringing a drug detection dog to sniff at the front door of a home was a search. In certain situations, law enforcement may perform a search when they have a reasonable suspicion of criminal activity, even if it falls short of probable cause necessary for an arrest.
Under Terry v. Ohio , law enforcement officers are permitted to conduct a limited warrantless search on a level of suspicion less than probable cause under certain circumstances. In Terry , the Supreme Court ruled that when a police officer witnesses "unusual conduct" that leads that officer to reasonably believe "that criminal activity may be afoot", that the suspicious person has a weapon and that the person is presently dangerous to the officer or others, the officer may conduct a "pat-down search" or "frisk" to determine whether the person is carrying a weapon.
To conduct a frisk, officers must be able to point to specific and articulable facts which, taken together with rational inferences from those facts, reasonably warrant their actions. Royer , such a search must be temporary, and questioning must be limited to the purpose of the stop e.
The Fourth Amendment proscribes unreasonable seizure of any person, person's home including its curtilage or personal property without a warrant.
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A seizure of property occurs when there is "some meaningful interference with an individual's possessory interests in that property",  such as when police officers take personal property away from an owner to use as evidence, or when they participate in an eviction. A seizure does not occur just because the government questions an individual in a public place.
The exclusionary rule would not bar voluntary answers to such questions from being offered into evidence in a subsequent criminal prosecution. The person is not being seized if his freedom of movement is not restrained. His refusal to listen or answer does not by itself furnish such grounds.
In United States v. Mendenhall , the Court held that a person is seized only when, by means of physical force or show of authority, his freedom of movement is restrained and, in the circumstances surrounding the incident, a reasonable person would believe that he was not free to leave. Bostick , the Court ruled that as long as the police do not convey a message that compliance with their requests is required, the police contact is a "citizen encounter" that falls outside the protections of the Fourth Amendment.