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.
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 "the facts and circumstances within [an officer's] knowledge and of which they had reasonably trustworthy information [are] sufficient to warrant a prudent man in believing that [a suspect] had committed or was committing an offense."
In criminal procedure law of the United States, an exigent circumstance allows law enforcement to enter a structure without a search warrant, or if they have a "knock and announce" warrant, allows them to enter without knocking and waiting for the owner's permission to enter. It must be a situation where people are in imminent danger, evidence faces imminent destruction, or a suspect's escape is imminent. Once entry is obtained, the plain view doctrine applies, allowing the seizure of any evidence or contraband discovered in the course of actions consequent upon the exigent circumstances.
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 Transportation Security Administration (TSA) officers while screening persons and property at U.S. airports.
Knock-and-announce, in United States law criminal procedure, is an ancient common law principle, incorporated into the Fourth Amendment, which requires law enforcement officers to announce their presence and provide residents with an opportunity to open the door prior to a search.
Hartman v. Moore, 547 U.S. 250 (2006), is a decision by the Supreme Court of the United States involving the pleading standard for retaliatory prosecution claims against government officials. After a successful lobbying attempt by the CEO of a manufacturing company against competing devices that the US Postal Service supported, the CEO found himself the target of an investigation by US postal inspectors and a criminal prosecution that was dismissed for lack of evidence. The CEO then filed suit against the inspectors and other government officials for seeking to prosecute him in retaliation for exercising his First Amendment rights to criticize postal policy. The Court ruled 5-2 that to prove that the prosecution was caused by a retaliatory motive, the plaintiff bringing such a claim must allege and prove that the criminal charges were brought without probable cause.
Consent searches are searches made by police officers in the United States based on the voluntary consent of the individual whose person or property is being searched. The simplest and most common type of warrantless searches in the United States are searches based upon consent. No warrant, probable cause or reasonable suspicion is required to perform a search if a person, or someone else with the proper authority, consents to a search.
The motor vehicle exception is a legal rule in the United States that modifies the normal probable cause requirement of the Fourth Amendment to the United States Constitution and, when applicable, allows a police officer to search a motor vehicle without a search warrant.
United States v. Johns, 469 U.S. 478 (1985), was a United States Supreme Court criminal law case holding that a three-day delay in searching a motor vehicle under government control did not violate the Fourth Amendment to the United States Constitution.
Disparate treatment is one kind of unlawful discrimination in US labor law. In the United States, it means unequal behavior toward someone because of a protected characteristic under Title VII of the United States Civil Rights Act. This contrasts with disparate impact, where an employer applies a neutral rule that treats everyone equally in form, but has a disadvantageous effect on some people of a protected characteristic compared to others.
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 federal probation and supervised release are imposed at sentencing. The difference between probation and supervised release is that the former is imposed as a substitute for imprisonment, or in addition to home detention, while the latter is imposed in addition to imprisonment. Probation and supervised release are both administered by the U.S. Probation and Pretrial Services System. Federal probation has existed since 1909, while supervised release has only existed since 1987, when it replaced federal parole as a means for imposing supervision following release from prison.
Inwood Laboratories Inc. v. Ives Laboratories, Inc., 456 U.S. 844 (1982), is a United States Supreme Court case, in which the Court confirmed the application of and set out a test for contributory trademark liability under § 32 of the Lanham Act.
Ornelas v. United States, 517 U.S. 690 (1996), was a case decided by the Supreme Court of the United States that held that appellate courts should review probable cause determinations for warrantless searches de novo.
County of Riverside v. McLaughlin, 500 U.S. 44 (1991), was a United States Supreme Court case which involved the question of within what period of time must a suspect arrested without a warrant be brought into court to determine if there is probable cause for holding the suspect in custody. The majority held that suspects must generally be granted a probable cause determination within 48 hours of arrest. The dissent believed that probable cause hearings should generally be provided much sooner, as soon as the police complete the administrative steps incident to arrest.
Glik v. Cunniffe, 655 F.3d 78 is a case in which the United States Court of Appeals for the First Circuit held that a private citizen has the right to record video and audio of police carrying out their duties in a public place, and that the arrest of the citizen for a wiretapping violation violated his First and Fourth Amendment rights. The case arose when Simon Glik filmed Boston, Massachusetts, police officers from the bicycle unit making an arrest in a public park. When the officers observed that Glik was recording the arrest, they arrested him and Glik was subsequently charged with wiretapping, disturbing the peace, and aiding in the escape of a prisoner. Glik then sued the City of Boston and the arresting officers, claiming that they violated his constitutional rights.
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.
Devenpeck v. Alford, 543 U.S. 146 (2004), was a United States Supreme Court decision dealing with warrantless arrests and the Fourth Amendment. The Court ruled that even if an officer wrongly arrests a suspect for one crime, the arrest may still be "reasonable" if there is objectively probable cause to believe that the suspect is involved in a different crime.
