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."
A traffic stop, commonly referred to as being pulled over, is a temporary detention of a driver of a vehicle and its occupants by police to investigate a possible crime or minor violation of law.
Reasonable suspicion is a legal standard of proof in United States law that is less than probable cause, the legal standard for arrests and warrants, but more than an "inchoate and unparticularized suspicion or 'hunch'"; it must be based on "specific and articulable facts", "taken together with rational inferences from those facts", and the suspicion must be associated with the specific individual. If police additionally have reasonable suspicion that a person so detained is armed and dangerous, they may "frisk" the person for weapons, but not for contraband like drugs. However, if the police develop probable cause during a weapons frisk, they may then conduct a full search. Reasonable suspicion is evaluated using the "reasonable person" or "reasonable officer" standard, in which said person in the same circumstances could reasonably suspect a person has been, is, or is about to be engaged in criminal activity; it depends upon the totality of circumstances, and can result from a combination of particular facts, even if each is individually innocuous.
Atwater v. Lago Vista, 532 U.S. 318 (2001), was a United States Supreme Court decision which held that a person's Fourth Amendment rights are not violated when the subject is arrested for driving without a seatbelt. The court ruled that such an arrest for a misdemeanor that is punishable only by a fine does not constitute an unreasonable seizure under the Fourth Amendment.
"Stop and identify" statutes are laws in several U.S. states that authorize police to lawfully order people whom they reasonably suspect of committing a crime to state their name. If there is not reasonable suspicion that a person has committed a crime, is committing a crime, or is about to commit a crime, the person is not required to identify themself, even in these states.
United States v. Grubbs, 547 U.S. 90 (2006), was a case decided by the Supreme Court of the United States involving the constitutionality of "anticipatory" search warrants under the Fourth Amendment to the United States Constitution. The Court ruled that such warrants, which are issued in advance of a "triggering condition" that makes them executable, are constitutional and do not need to describe that condition on their face.
The Supreme Court of the United States handed down six per curiam opinions during its 2004 term, which began October 4, 2004 and concluded October 3, 2005.
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.
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.
Kolender v. Lawson, 461 U.S. 352 (1983), is a United States Supreme Court case concerning the constitutionality of vague laws that allow police to demand that "loiterers" and "wanderers" provide "credible and reliable" identification.
Welsh v. Wisconsin, 466 U.S. 740 (1984), was a 1983 case before the US Supreme Court determining that a warrantless home arrest without exigent circumstances violates the Fourth Amendment protection against unlawful search and seizure.
Arizona v. Gant, 556 U.S. 332 (2009), was a United States Supreme Court decision holding that the Fourth Amendment to the United States Constitution requires law-enforcement officers to demonstrate an actual and continuing threat to their safety posed by an arrestee, or a need to preserve evidence related to the crime of arrest from tampering by the arrestee, in order to justify a warrantless vehicular search incident to arrest conducted after the vehicle's recent occupants have been arrested and secured.
"Contempt of cop" is law enforcement jargon in the United States for behavior by people toward law enforcement officers that the officers perceive as disrespectful or insufficiently deferential to their authority. It is a play on the phrase contempt of court, and is not an actual offense. The phrase is associated with unlawful arbitrary arrest and detention of individuals, often for expressing or exercising rights guaranteed to them by the United States Constitution. Contempt of cop is often discussed in connection to police misconduct such as use of excessive force or even police brutality as a reaction to perceived disrespectful behavior rather than for any legitimate law enforcement purpose.
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."
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.
Bailey v. United States, 568 U.S. 186 (2013), was a United States Supreme Court case concerning search and seizure. A 6–3 decision reversed the weapons conviction of a Long Island man who had been detained when police followed his vehicle after he left his apartment just before it was to be searched. Justice Anthony Kennedy wrote the majority opinion, and Antonin Scalia filed a concurrence. Stephen Breyer dissented.
The Supreme Court of the United States handed down eight per curiam opinions during its 2013 term, which began October 7, 2013 and concluded October 5, 2014.
Navarette v. California, 572 U.S. 393 (2014), was a case in which the United States Supreme Court clarified when police officers may make arrests or conduct temporary detentions based on information provided by anonymous tips. In 2008, police in California received a 911 call that a pickup truck was driving recklessly along a rural highway. Officers spotted a truck matching the description provided in the 911 call and followed the truck for five minutes, but did not observe any suspicious behavior. Nevertheless, officers conducted a traffic stop and discovered 30 pounds (14 kg) of marijuana in the truck. At trial, the occupants of the car argued that the traffic stop violated the Fourth Amendment of the United States Constitution, because the tip was unreliable, and officers did not personally observe criminal activity. Writing for a majority of the Court, Justice Clarence Thomas held that the 911 call was reliable, and that officers need not personally observe criminal activity when acting upon information provided by an anonymous 911 call.
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."
