2.20: Chapter 21 - Reasonable Suspicion

In this chapter we review the Court’s efforts to define “reasonable suspicion,” which is required for stops and frisks under Terry v. Ohio. Critics of stop and frisk practices complain that the Court has set too low a standard, thereby allowing law enforcement to stop pretty much anyone, particularly in neighborhoods with high crime rates. Advocates for stop and frisk counter that a stricter standard would undermine effective policework.

Supreme Court of the United States

United States v. Ralph Arvizu

Decided Jan. 15, 2002 – 534 U.S. 266

Chief Justice REHNQUIST delivered the opinion of the [unanimous] Court.

Respondent Ralph Arvizu was stopped by a border patrol agent while driving on an unpaved road in a remote area of southeastern Arizona. A search of his vehicle turned up more than 100 pounds of marijuana.

On an afternoon in January 1998, Agent Clinton Stoddard was working at a border patrol checkpoint along U.S. Highway 191 approximately 30 miles north of Douglas, Arizona. Douglas has a population of about 13,000 and is situated on the United States-Mexico border in the southeastern part of the State. Only two highways lead north from Douglas. Highway 191 leads north to Interstate 10, which passes through Tucson and Phoenix. State Highway 80 heads northeast through less populated areas toward New Mexico, skirting south and east of the portion of the Coronado National Forest that lies approximately 20 miles northeast of Douglas.

The checkpoint is located at the intersection of 191 and Rucker Canyon Road, an unpaved east-west road that connects 191 and the Coronado National Forest. When the checkpoint is operational, border patrol agents stop the traffic on 191 as part of a coordinated effort to stem the flow of illegal immigration and smuggling across the international border. Agents use roving patrols to apprehend smugglers trying to circumvent the checkpoint by taking the backroads, including those roads through the sparsely populated area between Douglas and the national forest. Magnetic sensors, or “intrusion devices,” facilitate agents’ efforts in patrolling these areas. Directionally sensitive, the sensors signal the passage of traffic that would be consistent with smuggling activities.

Sensors are located along the only other northbound road from Douglas besides Highways 191 and 80: Leslie Canyon Road. Leslie Canyon Road runs roughly parallel to 191, about halfway between 191 and the border of the Coronado National Forest, and ends when it intersects Rucker Canyon Road. It is unpaved beyond the 10-mile stretch leading out of Douglas and is very rarely traveled except for use by local ranchers and forest service personnel. Smugglers commonly try to avoid the 191 checkpoint by heading west on Rucker Canyon Road from Leslie Canyon Road and thence to Kuykendall Cutoff Road, a primitive dirt road that leads north approximately 12 miles east of 191. From there, they can gain access to Tucson and Phoenix.

Around 2:15 p.m., Stoddard received a report via Douglas radio that a Leslie Canyon Road sensor had been triggered. This was significant to Stoddard for two reasons. First, it suggested to him that a vehicle might be trying to circumvent the checkpoint. Second, the timing coincided with the point when agents begin heading back to the checkpoint for a shift change, which leaves the area unpatrolled.

Stoddard drove eastbound on Rucker Canyon Road to investigate. As he did so, he received another radio report of sensor activity. It indicated that the vehicle that had triggered the first sensor was heading westbound on Rucker Canyon Road. He saw the dust trail of an approaching vehicle about a half mile away. Stoddard had not seen any other vehicles and, based on the timing, believed that this was the one that had tripped the sensors. He pulled off to the side of the road at a slight slant so he could get a good look at the oncoming vehicle as it passed by.

It was a minivan, a type of automobile that Stoddard knew smugglers used. As it approached, it slowed dramatically, from about 50-55 to 25-30 miles per hour. He saw five occupants inside. An adult man was driving, an adult woman sat in the front passenger seat, and three children were in the back. The driver appeared stiff and his posture very rigid. He did not look at Stoddard and seemed to be trying to pretend that Stoddard was not there. Stoddard thought this suspicious because in his experience on patrol most persons look over and see what is going on, and in that area most drivers give border patrol agents a friendly wave. Stoddard noticed that the knees of the two children sitting in the very back seat were unusually high, as if their feet were propped up on some cargo on the floor.

At that point, Stoddard decided to get a closer look, so he began to follow the vehicle as it continued westbound. Shortly thereafter, all of the children, though still facing forward, put their hands up at the same time and began to wave at Stoddard in an abnormal pattern. It looked to Stoddard as if the children were being instructed. Their odd waving continued on and off for about four to five minutes.

Several hundred feet before the Kuykendall Cutoff Road intersection, the driver signaled that he would turn. At one point, the driver turned the signal off, but just as he approached the intersection he put it back on and abruptly turned north onto Kuykendall. The turn was significant to Stoddard because it was made at the last place that would have allowed the minivan to avoid the checkpoint. Also, Kuykendall, though passable by a sedan or van, is rougher than either Rucker Canyon or Leslie Canyon Roads, and the normal traffic is four-wheel-drive vehicles. Stoddard did not recognize the minivan as part of the local traffic agents encounter on patrol, and he did not think it likely that the minivan was going to or coming from a picnic outing. He was not aware of any picnic grounds on Turkey Creek, which could be reached by following Kuykendall Cutoff all the way up. He knew of picnic grounds and a Boy Scout camp east of the intersection of Rucker Canyon and Leslie Canyon Roads, but the minivan had turned west at that intersection. And he had never seen anyone picnicking or sightseeing near where the first sensor went off.

Stoddard radioed for a registration check and learned that the minivan was registered to an address in Douglas that was four blocks north of the border in an area notorious for alien and narcotics smuggling. After receiving the information, Stoddard decided to make a vehicle stop. He approached the driver and learned that his name was Ralph Arvizu. Stoddard asked if respondent would mind if he looked inside and searched the vehicle. Respondent agreed, and Stoddard discovered marijuana in a black duffel bag under the feet of the two children in the back seat. Another bag containing marijuana was behind the rear seat. In all, the van contained 128.85 pounds of marijuana, worth an estimated $99,080.

Respondent was charged with possession with intent to distribute marijuana. He moved to suppress the marijuana, arguing among other things that Stoddard did not have reasonable suspicion to stop the vehicle as required by the Fourth Amendment. After holding a hearing where Stoddard and respondent testified, the District Court for the District of Arizona ruled otherwise. The Court of Appeals for the Ninth Circuit reversed. We granted certiorari to review the decision of the Court of Appeals.

The Fourth Amendment prohibits “unreasonable searches and seizures” by the Government, and its protections extend to brief investigatory stops of persons or vehicles that fall short of traditional arrest. Because the “balance between the public interest and the individual’s right to personal security” tilts in favor of a standard less than probable cause in such cases, the Fourth Amendment is satisfied if the officer’s action is supported by reasonable suspicion to believe that criminal activity “‘may be afoot.’”

When discussing how reviewing courts should make reasonable-suspicion determinations, we have said repeatedly that they must look at the “totality of the circumstances” of each case to see whether the detaining officer has a “particularized and objective basis” for suspecting legal wrongdoing. This process allows officers to draw on their own experience and specialized training to make inferences from and deductions about the cumulative information available to them that “might well elude an untrained person.” Although an officer’s reliance on a mere “‘hunch’” is insufficient to justify a stop, the likelihood of criminal activity need not rise to the level required for probable cause, and it falls considerably short of satisfying a preponderance of the evidence standard.

Our cases have recognized that the concept of reasonable suspicion is somewhat abstract. But we have deliberately avoided reducing it to “‘a neat set of legal rules.’” We think that the approach taken by the Court of Appeals here departs sharply from the teachings of these cases. [It] does not take into account the “totality of the circumstances,” as our cases have understood that phrase. The court appeared to believe that each observation by Stoddard that was by itself readily susceptible to an innocent explanation was entitled to “no weight.” Terry, however, precludes this sort of divide-and-conquer analysis.

[T]he Court of Appeals’ approach would seriously undercut the “totality of the circumstances” principle which governs the existence vel non of “reasonable suspicion.” Take, for example, the court’s positions that respondent’s deceleration could not be considered because “slowing down after spotting a law enforcement vehicle is an entirely normal response that is in no way indicative of criminal activity” and that his failure to acknowledge Stoddard’s presence provided no support because there were “no ‘special circumstances’ rendering ‘innocent avoidance … improbable.’” We think it quite reasonable that a driver’s slowing down, stiffening of posture, and failure to acknowledge a sighted law enforcement officer might well be unremarkable in one instance (such as a busy San Francisco highway) while quite unusual in another (such as a remote portion of rural southeastern Arizona). Stoddard was entitled to make an assessment of the situation in light of his specialized training and familiarity with the customs of the area’s inhabitants. To the extent that a totality of the circumstances approach may render appellate review less circumscribed by precedent than otherwise, it is the nature of the totality rule.

Having considered the totality of the circumstances and given due weight to the factual inferences drawn by the law enforcement officer and District Court Judge, we hold that Stoddard had reasonable suspicion to believe that respondent was engaged in illegal activity. It was reasonable for Stoddard to infer from his observations, his registration check, and his experience as a border patrol agent that respondent had set out from Douglas along a little-traveled route used by smugglers to avoid the 191 checkpoint. Stoddard’s knowledge further supported a commonsense inference that respondent intended to pass through the area at a time when officers would be leaving their backroads patrols to change shifts. The likelihood that respondent and his family were on a picnic outing was diminished by the fact that the minivan had turned away from the known recreational areas. Corroborating this inference was the fact that recreational areas farther to the north would have been easier to reach by taking 191, as opposed to the 40-to-50–mile trip on unpaved and primitive roads. The children’s elevated knees suggested the existence of concealed cargo in the passenger compartment. Finally, Stoddard’s assessment of respondent’s reactions upon seeing him and the children’s mechanical-like waving, which continued for a full four to five minutes, were entitled to some weight.

A determination that reasonable suspicion exists [] need not rule out the possibility of innocent conduct. Undoubtedly, each of these factors alone is susceptible of innocent explanation, and some factors are more probative than others. Taken together, we believe they sufficed to form a particularized and objective basis for Stoddard’s stopping the vehicle, making the stop reasonable within the meaning of the Fourth Amendment.

The judgment of the Court of Appeals is therefore reversed, and the case is remanded for further proceedings consistent with this opinion.

* * *

In California v. Hodari D. (Chapter 19), the majority speculated in a footnote whether “it would be unreasonable to stop, for brief inquiry, young men who scatter in panic upon the mere sighting of the police,” and the dissent retorted that innocent persons might flee police for a variety of reasons. Because the question was not before the Court, the Justices did not decide whether flight from police was sufficiently suspicious to justify—by itself—a Terry stop. In the next case, the Court considered the merits of the question.

Supreme Court of the United States

Illinois v. William aka Sam Wardlow

Decided Jan. 12, 2000 – 528 U.S. 119

Chief Justice REHNQUIST delivered the opinion of the Court.

Respondent Wardlow fled upon seeing police officers patrolling an area known for heavy narcotics trafficking. Two of the officers caught up with him, stopped him and conducted a protective patdown search for weapons. Discovering a .38-caliber handgun, the officers arrested Wardlow. We hold that the officers’ stop did not violate the Fourth Amendment to the United States Constitution.

On September 9, 1995, Officers Nolan and Harvey were working as uniformed officers in the special operations section of the Chicago Police Department. The officers were driving the last car of a four car caravan converging on an area known for heavy narcotics trafficking in order to investigate drug transactions. The officers were traveling together because they expected to find a crowd of people in the area, including lookouts and customers.

As the caravan passed 4035 West Van Buren, Officer Nolan observed respondent Wardlow standing next to the building holding an opaque bag. Respondent looked in the direction of the officers and fled. Nolan and Harvey turned their car southbound, watched him as he ran through the gangway and an alley, and eventually cornered him on the street. Nolan then exited his car and stopped respondent. He immediately conducted a protective patdown search for weapons because in his experience it was common for there to be weapons in the near vicinity of narcotics transactions. During the frisk, Officer Nolan squeezed the bag respondent was carrying and felt a heavy, hard object similar to the shape of a gun. The officer then opened the bag and discovered a .38-caliber handgun with five live rounds of ammunition. The officers arrested Wardlow.

The Illinois trial court denied respondent’s motion to suppress, finding the gun was recovered during a lawful stop and frisk. The Illinois Appellate Court reversed Wardlow’s conviction, concluding that the gun should have been suppressed. The Illinois Supreme Court held that the stop and subsequent arrest violated the Fourth Amendment. We granted certiorari and now reverse.

This case, involving a brief encounter between a citizen and a police officer on a public street, is governed by the analysis we first applied in Terry. In Terry, we held that an officer may, consistent with the Fourth Amendment, conduct a brief, investigatory stop when the officer has a reasonable, articulable suspicion that criminal activity is afoot. While “reasonable suspicion” is a less demanding standard than probable cause and requires a showing considerably less than preponderance of the evidence, the Fourth Amendment requires at least a minimal level of objective justification for making the stop. The officer must be able to articulate more than an “inchoate and unparticularized suspicion or ‘hunch’” of criminal activity.

Nolan and Harvey were among eight officers in a four-car caravan that was converging on an area known for heavy narcotics trafficking, and the officers anticipated encountering a large number of people in the area, including drug customers and individuals serving as lookouts. It was in this context that Officer Nolan decided to investigate Wardlow after observing him flee. An individual’s presence in an area of expected criminal activity, standing alone, is not enough to support a reasonable, particularized suspicion that the person is committing a crime. But officers are not required to ignore the relevant characteristics of a location in determining whether the circumstances are sufficiently suspicious to warrant further investigation. Accordingly, we have previously noted the fact that the stop occurred in a “high crime area” among the relevant contextual considerations in a Terry analysis.

In this case, moreover, it was not merely respondent’s presence in an area of heavy narcotics trafficking that aroused the officers’ suspicion, but his unprovoked flight upon noticing the police. Our cases have also recognized that nervous, evasive behavior is a pertinent factor in determining reasonable suspicion. Headlong flight—wherever it occurs—is the consummate act of evasion: It is not necessarily indicative of wrongdoing, but it is certainly suggestive of such. In reviewing the propriety of an officer’s conduct, courts do not have available empirical studies dealing with inferences drawn from suspicious behavior, and we cannot reasonably demand scientific certainty from judges or law enforcement officers where none exists. Thus, the determination of reasonable suspicion must be based on commonsense judgments and inferences about human behavior. We conclude Officer Nolan was justified in suspecting that Wardlow was involved in criminal activity, and, therefore, in investigating further.

Such a holding is entirely consistent with our decision in Florida v. Royer, [460 U.S. 491 (1983)] where we held that when an officer, without reasonable suspicion or probable cause, approaches an individual, the individual has a right to ignore the police and go about his business. And any “refusal to cooperate, without more, does not furnish the minimal level of objective justification needed for a detention or seizure.” But unprovoked flight is simply not a mere refusal to cooperate. Flight, by its very nature, is not “going about one’s business”; in fact, it is just the opposite. Allowing officers confronted with such flight to stop the fugitive and investigate further is quite consistent with the individual’s right to go about his business or to stay put and remain silent in the face of police questioning.

Terry accepts the risk that officers may stop innocent people. Indeed, the Fourth Amendment accepts that risk in connection with more drastic police action; persons arrested and detained on probable cause to believe they have committed a crime may turn out to be innocent. The Terry stop is a far more minimal intrusion, simply allowing the officer to briefly investigate further. If the officer does not learn facts rising to the level of probable cause, the individual must be allowed to go on his way. But in this case the officers found respondent in possession of a handgun, and arrested him for violation of an Illinois firearms statute. No question of the propriety of the arrest itself is before us.

The judgment of the Supreme Court of Illinois is reversed, and the cause is remanded for further proceedings not inconsistent with this opinion.

Justice STEVENS, with whom Justice SOUTER, Justice GINSBURG, and Justice BREYER join, concurring in part and dissenting in part.

[The dissent agreed with the majority that flight from police could sometimes create cause for suspicion and thereby “by itself, be sufficient to justify a temporary investigative stop of the kind authorized by Terry.” It agreed too that the Court was correct in not “authorizing the temporary detention of anyone who flees at the mere sight of a police officer.” In other words, sometimes flight alone justifies a Terry stop, and sometimes it does not. “Given the diversity and frequency of possible motivations for flight, it would be profoundly unwise to endorse either per se rule.” The dissent differed from the majority in its discussion of why innocent persons might flee from officers:]

Among some citizens, particularly minorities and those residing in high crime areas, there is also the possibility that the fleeing person is entirely innocent, but, with or without justification, believes that contact with the police can itself be dangerous, apart from any criminal activity associated with the officer’s sudden presence. For such a person, unprovoked flight is neither “aberrant” nor “abnormal.” Moreover, these concerns and fears are known to the police officers themselves, and are validated by law enforcement investigations into their own practices. Accordingly, the evidence supporting the reasonableness of these beliefs is too pervasive to be dismissed as random or rare, and too persuasive to be disparaged as inconclusive or insufficient.

[The dissent quoted from Alberty v. United States, 162 U.S. 499, 511 (1896), as follows:]

“[I]t is a matter of common knowledge that men who are entirely innocent do sometimes fly from the scene of a crime through fear of being apprehended as the guilty parties, or from an unwillingness to appear as witnesses. Nor is it true as an accepted axiom of criminal law that ‘the wicked flee when no man pursueth, but the righteous are as bold as a lion.’ Innocent men sometimes hesitate to confront a jury—not necessarily because they fear that the jury will not protect them, but because they do not wish their names to appear in connection with criminal acts, are humiliated at being obliged to incur the popular odium of an arrest and trial, or because they do not wish to be put to the annoyance or expense of defending themselves.”

[The dissent then concluded “that in this case the brief testimony of the officer who seized respondent does not justify the conclusion that he had reasonable suspicion to make the stop.” The dissent argued that the officer’s testimony was vague and could not even demonstrate that Wardlow’s “flight was related to his expectation of police focus on him.”]

Notes, Comments, and Questions

The Court in Wardlow announced that “unprovoked flight” in a “high crime area”—particularly “an area of heavy narcotics trafficking”—justifies a Terry stop. It is not certain what other factors, when combined with flight, are sufficient to constitute reasonable suspicion. It seems likely, however, that once flight is part of the analysis, not much additional ground for suspicion is needed to give officers discretion to stop a suspect.

What guidance does the Court give on what a “high-crime area” is? What comes to your mind as you think of high-crime areas? Would official statistics (for example, records of arrests organized by neighborhood) provide an accurate picture of which neighborhoods have the most crime? How do race and poverty play into our notions of high crime areas? Is a fraternity house (or a neighborhood of such houses, nicknamed “Greektown”) a high-crime area? Why or why not?

Consider a college student fleeing a police officer who arrives at a fraternity party in response to a noise complaint. May the officer chase the student down and conduct a Terry stop? Why or why not?

Now imagine that same college student is walking in a high-poverty, primarily minority neighborhood in the middle of an afternoon. He sees two police officers walking toward him, and he runs in the other direction. Does this conduct justify Terry stop? Why or why not?

As students have likely already noticed, a great deal of Fourth Amendment cases result from enforcement of laws banning the possession, manufacture, and sale of certain drugs. Because police spend substantial time on drug enforcement, officers have come to recognize common characteristics and behaviors of persons involved in the drug trade. The next case concerns the relevance of such observations to a finding of reasonable suspicion.

Supreme Court of the United States

United States v. Andrew Sokolow

Decided April 3, 1989 – 490 U.S. 1

Chief Justice REHNQUIST delivered the opinion of the Court.

Respondent Andrew Sokolow was stopped by Drug Enforcement Administration (DEA) agents upon his arrival at Honolulu International Airport. The agents found 1,063 grams of cocaine in his carry-on luggage. When respondent was stopped, the agents knew, inter alia, that (1) he paid $2,100 for two airplane tickets from a roll of $20 bills; (2) he traveled under a name that did not match the name under which his telephone number was listed; (3) his original destination was Miami, a source city for illicit drugs; (4) he stayed in Miami for only 48 hours, even though a round-trip flight from Honolulu to Miami takes 20 hours; (5) he appeared nervous during his trip; and (6) he checked none of his luggage. A divided panel of the United States Court of Appeals for the Ninth Circuit held that the DEA agents did not have a reasonable suspicion to stop respondent, as required by the Fourth Amendment. We take the contrary view.

This case involves a typical attempt to smuggle drugs through one of the Nation’s airports. On a Sunday in July 1984, respondent went to the United Airlines ticket counter at Honolulu Airport, where he purchased two round-trip tickets for a flight to Miami leaving later that day. The tickets were purchased in the names of “Andrew Kray” and “Janet Norian” and had open return dates. Respondent paid $2,100 for the tickets from a large roll of $20 bills, which appeared to contain a total of $4,000. He also gave the ticket agent his home telephone number. The ticket agent noticed that respondent seemed nervous; he was about 25 years old; he was dressed in a black jumpsuit and wore gold jewelry; and he was accompanied by a woman, who turned out to be Janet Norian. Neither respondent nor his companion checked any of their four pieces of luggage.

After the couple left for their flight, the ticket agent informed Officer John McCarthy of the Honolulu Police Department of respondent’s cash purchase of tickets to Miami. Officer McCarthy determined that the telephone number respondent gave to the ticket agent was subscribed to a “Karl Herman,” who resided at 348-A Royal Hawaiian Avenue in Honolulu. Unbeknownst to McCarthy (and later to the DEA agents), respondent was Herman’s roommate. The ticket agent identified respondent’s voice on the answering machine at Herman’s number. Officer McCarthy was unable to find any listing under the name “Andrew Kray” in Hawaii. McCarthy subsequently learned that return reservations from Miami to Honolulu had been made in the names of Kray and Norian, with their arrival scheduled for July 25, three days after respondent and his companion had left. He also learned that Kray and Norian were scheduled to make stopovers in Denver and Los Angeles.

On July 25, during the stopover in Los Angeles, DEA agents identified respondent. He “appeared to be very nervous and was looking all around the waiting area.” Later that day, at 6:30 p.m., respondent and Norian arrived in Honolulu. As before, they had not checked their luggage. Respondent was still wearing a black jumpsuit and gold jewelry. The couple proceeded directly to the street and tried to hail a cab, where Agent Richard Kempshall and three other DEA agents approached them. Kempshall displayed his credentials, grabbed respondent by the arm, and moved him back onto the sidewalk. Kempshall asked respondent for his airline ticket and identification; respondent said that he had neither. He told the agents that his name was “Sokolow,” but that he was traveling under his mother’s maiden name, “Kray.”

Respondent and Norian were escorted to the DEA office at the airport. There, the couple’s luggage was examined by “Donker,” a narcotics detector dog, which alerted on respondent’s brown shoulder bag. The agents arrested respondent. He was advised of his constitutional rights and declined to make any statements. The agents obtained a warrant to search the shoulder bag. They found no illicit drugs, but the bag did contain several suspicious documents indicating respondent’s involvement in drug trafficking. The agents had Donker reexamine the remaining luggage, and this time the dog alerted on a medium-sized Louis Vuitton bag. By now, it was 9:30 p.m., too late for the agents to obtain a second warrant. They allowed respondent to leave for the night, but kept his luggage. The next morning, after a second dog confirmed Donker’s alert, the agents obtained a warrant and found 1,063 grams of cocaine inside the bag.

Respondent was indicted for possession with the intent to distribute cocaine. The United States District Court for Hawaii denied his motion to suppress the cocaine and other evidence seized from his luggage. Respondent then entered a conditional plea of guilty to the offense charged.

The United States Court of Appeals for the Ninth Circuit reversed respondent’s conviction by a divided vote. We granted certiorari to review the decision of the Court of Appeals. We now reverse.

The Court of Appeals held that the DEA agents seized respondent when they grabbed him by the arm and moved him back onto the sidewalk. The Government does not challenge that conclusion, and we assume—without deciding—that a stop occurred here. Our decision, then, turns on whether the agents had a reasonable suspicion that respondent was engaged in wrongdoing when they encountered him on the sidewalk.

The concept of reasonable suspicion, like probable cause, is not “readily, or even usefully, reduced to a neat set of legal rules.” We think the Court of Appeals’ effort to refine and elaborate the requirements of “reasonable suspicion” in this case creates unnecessary difficulty in dealing with one of the relatively simple concepts embodied in the Fourth Amendment. In evaluating the validity of a stop such as this, we must consider “the totality of the circumstances—the whole picture.”

The rule enunciated by the Court of Appeals, in which evidence available to an officer is divided into evidence of “ongoing criminal behavior,” on the one hand, and “probabilistic” evidence, on the other, is not in keeping with the [] statements from our decisions. It also seems to us to draw a sharp line between types of evidence, the probative value of which varies only in degree. The Court of Appeals classified evidence of traveling under an alias, or evidence that the suspect took an evasive or erratic path through an airport, as meeting the test for showing “ongoing criminal activity.” But certainly instances are conceivable in which traveling under an alias would not reflect ongoing criminal activity: for example, a person who wished to travel to a hospital or clinic for an operation and wished to conceal that fact. One taking an evasive path through an airport might be seeking to avoid a confrontation with an angry acquaintance or with a creditor. This is not to say that each of these types of evidence is not highly probative, but they do not have the sort of ironclad significance attributed to them by the Court of Appeals.

On the other hand, the factors in this case that the Court of Appeals treated as merely “probabilistic” also have probative significance. Paying $2,100 in cash for two airplane tickets is out of the ordinary, and it is even more out of the ordinary to pay that sum from a roll of $20 bills containing nearly twice that amount of cash. Most business travelers, we feel confident, purchase airline tickets by credit card or check so as to have a record for tax or business purposes, and few vacationers carry with them thousands of dollars in $20 bills. We also think the agents had a reasonable ground to believe that respondent was traveling under an alias; the evidence was by no means conclusive, but it was sufficient to warrant consideration. While a trip from Honolulu to Miami, standing alone, is not a cause for any sort of suspicion, here there was more: surely few residents of Honolulu travel from that city for 20 hours to spend 48 hours in Miami during the month of July. Any one of these factors is not by itself proof of any illegal conduct and is quite consistent with innocent travel. But we think taken together they amount to reasonable suspicion.

We do not agree with respondent that our analysis is somehow changed by the agents’ belief that his behavior was consistent with one of the DEA’s “drug courier profiles.” A court sitting to determine the existence of reasonable suspicion must require the agent to articulate the factors leading to that conclusion, but the fact that these factors may be set forth in a “profile” does not somehow detract from their evidentiary significance as seen by a trained agent.

We hold that the agents had a reasonable basis to suspect that respondent was transporting illegal drugs on these facts. The judgment of the Court of Appeals is therefore reversed, and the case is remanded for further proceedings consistent with our decision.

Justice MARSHALL, with whom Justice BRENNAN joins, dissenting.

Because the strongest advocates of Fourth Amendment rights are frequently criminals, it is easy to forget that our interpretations of such rights apply to the innocent and the guilty alike. In the present case, the chain of events set in motion when respondent Andrew Sokolow was stopped by Drug Enforcement Administration (DEA) agents at Honolulu International Airport led to the discovery of cocaine and, ultimately, to Sokolow’s conviction for drug trafficking. But in sustaining this conviction on the ground that the agents reasonably suspected Sokolow of ongoing criminal activity, the Court diminishes the rights of all citizens “to be secure in their persons,” as they traverse the Nation’s airports. Finding this result constitutionally impermissible, I dissent.

The Fourth Amendment cabins government’s authority to intrude on personal privacy and security by requiring that searches and seizures usually be supported by a showing of probable cause. The reasonable-suspicion standard is a derivation of the probable-cause command, applicable only to those brief detentions which fall short of being full-scale searches and seizures and which are necessitated by law enforcement exigencies such as the need to stop ongoing crimes, to prevent imminent crimes, and to protect law enforcement officers in highly charged situations. By requiring reasonable suspicion as a prerequisite to such seizures, the Fourth Amendment protects innocent persons from being subjected to “overbearing or harassing” police conduct carried out solely on the basis of imprecise stereotypes of what criminals look like, or on the basis of irrelevant personal characteristics such as race.

To deter such egregious police behavior, we have held that a suspicion is not reasonable unless officers have based it on “specific and articulable facts.” It is not enough to suspect that an individual has committed crimes in the past, harbors unconsummated criminal designs, or has the propensity to commit crimes. On the contrary, before detaining an individual, law enforcement officers must reasonably suspect that he is engaged in, or poised to commit, a criminal act at that moment.

In my view, a law enforcement officer’s mechanistic application of a formula of personal and behavioral traits in deciding whom to detain can only dull the officer’s ability and determination to make sensitive and fact-specific inferences “in light of his experience.” Reflexive reliance on a profile of drug courier characteristics runs a far greater risk than does ordinary, case-by-case police work of subjecting innocent individuals to unwarranted police harassment and detention. This risk is enhanced by the profile’s “chameleon-like way of adapting to any particular set of observations.” In asserting that it is not “somehow” relevant that the agents who stopped Sokolow did so in reliance on a prefabricated profile of criminal characteristics, the majority thus ducks serious issues relating to a questionable law enforcement practice, to address the validity of which we granted certiorari in this case.

* * *

Reasonable Suspicion Based on Tips

Police rely on information volunteered by persons outside of law enforcement to conduct investigations. Witnesses to crimes, suspects themselves, and others willing to provide relevant information to help officers do their work. The Court has decided a handful of cases concerning how much a “tip” from an informant contributes to a finding of reasonable suspicion.

Supreme Court of the United States

Alabama v. Vanessa Rose White

Decided June 11, 1990 – 496 U.S. 325

Justice WHITE delivered the opinion of the Court.

Based on an anonymous telephone tip, police stopped respondent’s vehicle. A consensual search of the car revealed drugs. The issue is whether the tip, as corroborated by independent police work, exhibited sufficient indicia of reliability to provide reasonable suspicion to make the investigatory stop. We hold that it did.

On April 22, 1987, at approximately 3 p.m., Corporal B.H. Davis of the Montgomery Police Department received a telephone call from an anonymous person, stating that Vanessa White would be leaving 235-C Lynwood Terrace Apartments at a particular time in a brown Plymouth station wagon with the right taillight lens broken, that she would be going to Dobey’s Motel, and that she would be in possession of about an ounce of cocaine inside a brown attaché case. Corporal Davis and his partner, Corporal P. A. Reynolds, proceeded to the Lynwood Terrace Apartments. The officers saw a brown Plymouth station wagon with a broken right taillight in the parking lot in front of the 235 building. The officers observed respondent leave the 235 building, carrying nothing in her hands, and enter the station wagon. They followed the vehicle as it drove the most direct route to Dobey’s Motel. When the vehicle reached the Mobile Highway, on which Dobey’s Motel is located, Corporal Reynolds requested a patrol unit to stop the vehicle. The vehicle was stopped at approximately 4:18 p.m., just short of Dobey’s Motel. Corporal Davis asked respondent to step to the rear of her car, where he informed her that she had been stopped because she was suspected of carrying cocaine in the vehicle. He asked if they could look for cocaine, and respondent said they could look. The officers found a locked brown attaché case in the car, and, upon request, respondent provided the combination to the lock. The officers found marijuana in the attaché case and placed respondent under arrest. During processing at the station, the officers found three milligrams of cocaine in respondent’s purse.

Respondent was charged in Montgomery County Court with possession of marijuana and possession of cocaine. The trial court denied respondent’s motion to suppress, and she pleaded guilty to the charges, reserving the right to appeal the denial of her suppression motion. The Court of Criminal Appeals of Alabama concluded that respondent’s motion to dismiss should have been granted and reversed her conviction. The Supreme Court of Alabama denied the State’s petition for writ of certiorari. [W]e granted the State’s petition for certiorari. We now reverse.

Reasonable suspicion is a less demanding standard than probable cause not only in the sense that reasonable suspicion can be established with information that is different in quantity or content than that required to establish probable cause, but also in the sense that reasonable suspicion can arise from information that is less reliable than that required to show probable cause. Reasonable suspicion, like probable cause, is dependent upon both the content of information possessed by police and its degree of reliability. Both factors—quantity and quality—are considered in the “totality of the circumstances—the whole picture” that must be taken into account when evaluating whether there is reasonable suspicion. Thus, if a tip has a relatively low degree of reliability, more information will be required to establish the requisite quantum of suspicion than would be required if the tip were more reliable. The [Illinois v.] Gates Court applied its totality-of-the-circumstances approach in this manner, taking into account the facts known to the officers from personal observation, and giving the anonymous tip the weight it deserved in light of its indicia of reliability as established through independent police work. The same approach applies in the reasonable-suspicion context, the only difference being the level of suspicion that must be established. Contrary to the court below, we conclude that when the officers stopped respondent, the anonymous tip had been sufficiently corroborated to furnish reasonable suspicion that respondent was engaged in criminal activity and that the investigative stop therefore did not violate the Fourth Amendment.

It is true that not every detail mentioned by the tipster was verified, such as the name of the woman leaving the building or the precise apartment from which she left; but the officers did corroborate that a woman left the 235 building and got into the particular vehicle that was described by the caller. With respect to the time of departure predicted by the informant, Corporal Davis testified that the caller gave a particular time when the woman would be leaving, but he did not state what that time was. He did testify that, after the call, he and his partner proceeded to the Lynwood Terrace Apartments to put the 235 building under surveillance. Given the fact that the officers proceeded to the indicated address immediately after the call and that respondent emerged not too long thereafter, it appears from the record before us that respondent’s departure from the building was within the timeframe predicted by the caller. As for the caller’s prediction of respondent’s destination, it is true that the officers stopped her just short of Dobey’s Motel and did not know whether she would have pulled in or continued past it. But given that the 4-mile route driven by respondent was the most direct route possible to Dobey’s Motel but nevertheless involved several turns, we think respondent’s destination was significantly corroborated.

The Court’s opinion in Gates gave credit to the proposition that because an informant is shown to be right about some things, he is probably right about other facts that he has alleged, including the claim that the object of the tip is engaged in criminal activity. Thus, it is not unreasonable to conclude in this case that the independent corroboration by the police of significant aspects of the informer’s predictions imparted some degree of reliability to the other allegations made by the caller.

We think it also important that, as in Gates, “the anonymous [tip] contained a range of details relating not just to easily obtained facts and conditions existing at the time of the tip, but to future actions of third parties ordinarily not easily predicted.” The fact that the officers found a car precisely matching the caller’s description in front of the 235 building is an example of the former. Anyone could have “predicted” that fact because it was a condition presumably existing at the time of the call. What was important was the caller’s ability to predict respondent’s future behavior, because it demonstrated inside information—a special familiarity with respondent’s affairs. The general public would have had no way of knowing that respondent would shortly leave the building, get in the described car, and drive the most direct route to Dobey’s Motel. Because only a small number of people are generally privy to an individual’s itinerary, it is reasonable for police to believe that a person with access to such information is likely to also have access to reliable information about that individual’s illegal activities. When significant aspects of the caller’s predictions were verified, there was reason to believe not only that the caller was honest but also that he was well informed, at least well enough to justify the stop.

Although it is a close case, we conclude that under the totality of the circumstances the anonymous tip, as corroborated, exhibited sufficient indicia of reliability to justify the investigatory stop of respondent’s car. We therefore reverse the judgment of the Court of Criminal Appeals of Alabama and remand the case for further proceedings not inconsistent with this opinion.

Justice STEVENS, with whom Justice BRENNAN and Justice MARSHALL join, dissenting.

Millions of people leave their apartments at about the same time every day carrying an attaché case and heading for a destination known to their neighbors. Usually, however, the neighbors do not know what the briefcase contains. An anonymous neighbor’s prediction about somebody’s time of departure and probable destination is anything but a reliable basis for assuming that the commuter is in possession of an illegal substance—particularly when the person is not even carrying the attaché case described by the tipster.

The record in this case does not tell us how often respondent drove from the Lynwood Terrace Apartments to Dobey’s Motel; for all we know, she may have been a room clerk or telephone operator working the evening shift. It does not tell us whether Officer Davis made any effort to ascertain the informer’s identity, his reason for calling, or the basis of his prediction about respondent’s destination. Indeed, for all that this record tells us, the tipster may well have been another police officer who had a “hunch” that respondent might have cocaine in her attaché case.

Anybody with enough knowledge about a given person to make her the target of a prank, or to harbor a grudge against her, will certainly be able to formulate a tip about her like the one predicting Vanessa White’s excursion. In addition, under the Court’s holding, every citizen is subject to being seized and questioned by any officer who is prepared to testify that the warrantless stop was based on an anonymous tip predicting whatever conduct the officer just observed. Fortunately, the vast majority of those in our law enforcement community would not adopt such a practice. But the Fourth Amendment was intended to protect the citizen from the overzealous and unscrupulous officer as well as from those who are conscientious and truthful. This decision makes a mockery of that protection.

I respectfully dissent.

* * *

The stop in White was made upon reasonable suspicion; then the suspect consented to the automobile search. Without consent, could the officer search the car? Why or why not?

In the next case, the Court distinguished Alabama v. White and found that the information provided by a tipster did not justify a Terry stop.

Supreme Court of the United States

Florida v. J.L.

Decided March 28, 2000 – 529 U.S. 266

Justice GINSBURG delivered the opinion of the [unanimous] Court.

The question presented in this case is whether an anonymous tip that a person is carrying a gun is, without more, sufficient to justify a police officer’s stop and frisk of that person. We hold that it is not.

I

On October 13, 1995, an anonymous caller reported to the Miami-Dade Police that a young black male standing at a particular bus stop and wearing a plaid shirt was carrying a gun. So far as the record reveals, there is no audio recording of the tip, and nothing is known about the informant. Sometime after the police received the tip—the record does not say how long—two officers were instructed to respond. They arrived at the bus stop about six minutes later and saw three black males “just hanging out [there].” One of the three, respondent J.L., was wearing a plaid shirt. Apart from the tip, the officers had no reason to suspect any of the three of illegal conduct. The officers did not see a firearm, and J.L. made no threatening or otherwise unusual movements. One of the officers approached J.L., told him to put his hands up on the bus stop, frisked him, and seized a gun from J.L.’s pocket. The second officer frisked the other two individuals, against whom no allegations had been made, and found nothing.

J.L., who was at the time of the frisk “10 days shy of his 16th birth[day],” was charged under state law with carrying a concealed firearm without a license and possessing a firearm while under the age of 18. He moved to suppress the gun as the fruit of an unlawful search, and the trial court granted his motion. The intermediate appellate court reversed, but the Supreme Court of Florida quashed that decision and held the search invalid under the Fourth Amendment. We granted certiorari and now affirm the judgment of the Florida Supreme Court.

II

Our “stop and frisk” decisions begin with Terry v. Ohio. In the instant case, the officers’ suspicion that J.L. was carrying a weapon arose not from any observations of their own but solely from a call made from an unknown location by an unknown caller. Unlike a tip from a known informant whose reputation can be assessed and who can be held responsible if her allegations turn out to be fabricated, “an anonymous tip alone seldom demonstrates the informant’s basis of knowledge or veracity.” As we have recognized, however, there are situations in which an anonymous tip, suitably corroborated, exhibits “sufficient indicia of reliability to provide reasonable suspicion to make the investigatory stop.” The question we here confront is whether the tip pointing to J.L. had those indicia of reliability.

The tip in the instant case lacked the moderate indicia of reliability present in [Alabama v.] White and essential to the Court’s decision in that case. The anonymous call concerning J.L. provided no predictive information and therefore left the police without means to test the informant’s knowledge or credibility. That the allegation about the gun turned out to be correct does not suggest that the officers, prior to the frisks, had a reasonable basis for suspecting J.L. of engaging in unlawful conduct: The reasonableness of official suspicion must be measured by what the officers knew before they conducted their search. All the police had to go on in this case was the bare report of an unknown, unaccountable informant who neither explained how he knew about the gun nor supplied any basis for believing he had inside information about J.L. If White was a close case on the reliability of anonymous tips, this one surely falls on the other side of the line.

Florida contends that the tip was reliable because its description of the suspect’s visible attributes proved accurate: There really was a young black male wearing a plaid shirt at the bus stop. The United States as amicus curiae makes a similar argument, proposing that a stop and frisk should be permitted “when (1) an anonymous tip provides a description of a particular person at a particular location illegally carrying a concealed firearm, (2) police promptly verify the pertinent details of the tip except the existence of the firearm, and (3) there are no factors that cast doubt on the reliability of the tip….” These contentions misapprehend the reliability needed for a tip to justify a Terry stop.

An accurate description of a subject’s readily observable location and appearance is of course reliable in this limited sense: It will help the police correctly identify the person whom the tipster means to accuse. Such a tip, however, does not show that the tipster has knowledge of concealed criminal activity. The reasonable suspicion here at issue requires that a tip be reliable in its assertion of illegality, not just in its tendency to identify a determinate person.

A second major argument advanced by Florida and the United States as amicus is, in essence, that the standard Terry analysis should be modified to license a “firearm exception.” Under such an exception, a tip alleging an illegal gun would justify a stop and frisk even if the accusation would fail standard pre-search reliability testing. We decline to adopt this position.

Firearms are dangerous, and extraordinary dangers sometimes justify unusual precautions. Our decisions recognize the serious threat that armed criminals pose to public safety; Terry’s rule, which permits protective police searches on the basis of reasonable suspicion rather than demanding that officers meet the higher standard of probable cause, responds to this very concern. But an automatic firearm exception to our established reliability analysis would rove too far. Such an exception would enable any person seeking to harass another to set in motion an intrusive, embarrassing police search of the targeted person simply by placing an anonymous call falsely reporting the target’s unlawful carriage of a gun. Nor could one securely confine such an exception to allegations involving firearms. If police officers may properly conduct Terry frisks on the basis of bare-boned tips about guns, it would be reasonable to maintain [] that the police should similarly have discretion to frisk based on bare-boned tips about narcotics. As we clarified when we made indicia of reliability critical in Adams [v. Williams, 407 U.S.143 (1972),] and White, the Fourth Amendment is not so easily satisfied.

The facts of this case do not require us to speculate about the circumstances under which the danger alleged in an anonymous tip might be so great as to justify a search even without a showing of reliability. We do not say, for example, that a report of a person carrying a bomb need bear the indicia of reliability we demand for a report of a person carrying a firearm before the police can constitutionally conduct a frisk. Nor do we hold that public safety officials in quarters where the reasonable expectation of Fourth Amendment privacy is diminished, such as airports and schools, cannot conduct protective searches on the basis of information insufficient to justify searches elsewhere.

Finally, the requirement that an anonymous tip bear standard indicia of reliability in order to justify a stop in no way diminishes a police officer’s prerogative, in accord with Terry, to conduct a protective search of a person who has already been legitimately stopped. We speak in today’s decision only of cases in which the officer’s authority to make the initial stop is at issue. In that context, we hold that an anonymous tip lacking indicia of reliability of the kind contemplated in Adams and White does not justify a stop and frisk whenever and however it alleges the illegal possession of a firearm.

The judgment of the Florida Supreme Court is affirmed.

* * *

Look closely at the tips in White and J.L. Is there a good basis for distinguishing the two? Would you be able to predict when an officer should (and should not) form reasonable suspicion from a tip?

In 2014, the Court applied White and J.L. to a tip concerning a dangerous driver on a California highway. As the caustic dissent indicates, the Court’s decision in Navarette v. California has been widely read as lowering the amount of evidence necessary to support a finding of reasonable suspicion.

Supreme Court of the United States

Lorenzo Prado Navarette v. California

Decided April 22, 2014 – 572 U.S. 393

Justice THOMAS delivered the opinion of the Court.

After a 911 caller reported that a vehicle had run her off the road, a police officer located the vehicle she identified during the call and executed a traffic stop. We hold that the stop complied with the Fourth Amendment because, under the totality of the circumstances, the officer had reasonable suspicion that the driver was intoxicated.

I

On August 23, 2008, a Mendocino County 911 dispatch team for the California Highway Patrol (CHP) received a call from another CHP dispatcher in neighboring Humboldt County. The Humboldt County dispatcher relayed a tip from a 911 caller, which the Mendocino County team recorded as follows: “‘Showing southbound Highway 1 at mile marker 88, Silver Ford 150 pickup. Plate of 8-David-94925. Ran the reporting party off the roadway and was last seen approximately five [minutes] ago.’” The Mendocino County team then broadcast that information to CHP officers at 3:47 p.m.

A CHP officer heading northbound toward the reported vehicle responded to the broadcast. At 4:00 p.m., the officer passed the truck near mile marker 69. At about 4:05 p.m., after making a U-turn, he pulled the truck over. A second officer, who had separately responded to the broadcast, also arrived on the scene. As the two officers approached the truck, they smelled marijuana. A search of the truck bed revealed 30 pounds of marijuana. The officers arrested the driver, petitioner Lorenzo Prado Navarette, and the passenger, petitioner José Prado Navarette.

Petitioners moved to suppress the evidence, arguing that the traffic stop violated the Fourth Amendment because the officer lacked reasonable suspicion of criminal activity. Both the magistrate who presided over the suppression hearing and the Superior Court disagreed. Petitioners pleaded guilty to transporting marijuana and were sentenced to 90 days in jail plus three years of probation.

The California Court of Appeal affirmed. The California Supreme Court denied review. We granted certiorari and now affirm.

II

The Fourth Amendment permits brief investigative stops—such as the traffic stop in this case—when a law enforcement officer has “a particularized and objective basis for suspecting the particular person stopped of criminal activity.” The “reasonable suspicion” necessary to justify such a stop “is dependent upon both the content of information possessed by police and its degree of reliability.” The standard takes into account “the totality of the circumstances—the whole picture.” Although a mere “‘hunch’” does not create reasonable suspicion, the level of suspicion the standard requires is “considerably less than proof of wrongdoing by a preponderance of the evidence,” and “obviously less” than is necessary for probable cause.

These principles apply with full force to investigative stops based on information from anonymous tips. We have firmly rejected the argument “that reasonable cause for a[n investigative stop] can only be based on the officer’s personal observation, rather than on information supplied by another person.” Of course, “an anonymous tip alone seldom demonstrates the informant’s basis of knowledge or veracity.” That is because “ordinary citizens generally do not provide extensive recitations of the basis of their everyday observations,” and an anonymous tipster’s veracity is “‘by hypothesis largely unknown, and unknowable.’” But under appropriate circumstances, an anonymous tip can demonstrate “sufficient indicia of reliability to provide reasonable suspicion to make [an] investigatory stop.”

The initial question in this case is whether the 911 call was sufficiently reliable to credit the allegation that petitioners’ truck “ran the [caller] off the roadway.” Even assuming for present purposes that the 911 call was anonymous, we conclude that the call bore adequate indicia of reliability for the officer to credit the caller’s account. The officer was therefore justified in proceeding from the premise that the truck had, in fact, caused the caller’s car to be dangerously diverted from the highway.

By reporting that she had been run off the road by a specific vehicle—a silver Ford F-150 pickup, license plate 8D94925—the caller necessarily claimed eyewitness knowledge of the alleged dangerous driving. That basis of knowledge lends significant support to the tip’s reliability. A driver’s claim that another vehicle ran her off the road [] necessarily implies that the informant knows the other car was driven dangerously.

There is also reason to think that the 911 caller in this case was telling the truth. Police confirmed the truck’s location near mile marker 69 (roughly 19 highway miles south of the location reported in the 911 call) at 4:00 p.m. (roughly 18 minutes after the 911 call). That timeline of events suggests that the caller reported the incident soon after she was run off the road. That sort of contemporaneous report has long been treated as especially reliable.

Another indicator of veracity is the caller’s use of the 911 emergency system. A 911 call has some features that allow for identifying and tracing callers, and thus provide some safeguards against making false reports with immunity. As this case illustrates, 911 calls can be recorded, which provides victims with an opportunity to identify the false tipster’s voice and subject him to prosecution. The 911 system also permits law enforcement to verify important information about the caller. None of this is to suggest that tips in 911 calls are per se reliable. Given the foregoing technological and regulatory developments, however, a reasonable officer could conclude that a false tipster would think twice before using such a system. The caller’s use of the 911 system is therefore one of the relevant circumstances that, taken together, justified the officer’s reliance on the information reported in the 911 call.

Even a reliable tip will justify an investigative stop only if it creates reasonable suspicion that “criminal activity may be afoot.” We must therefore determine whether the 911 caller’s report of being run off the roadway created reasonable suspicion of an ongoing crime such as drunk driving as opposed to an isolated episode of past recklessness. We conclude that the behavior alleged by the 911 caller, “viewed from the standpoint of an objectively reasonable police officer, amount[s] to reasonable suspicion” of drunk driving. The stop was therefore proper.

Reasonable suspicion depends on “‘“the factual and practical considerations of everyday life on which reasonable and prudent men, not legal technicians, act.”’” Under that commonsense approach, we can appropriately recognize certain driving behaviors as sound indicia of drunk driving. Indeed, the accumulated experience of thousands of officers suggests that these sorts of erratic behaviors are strongly correlated with drunk driving. Of course, not all traffic infractions imply intoxication. Unconfirmed reports of driving without a seatbelt or slightly over the speed limit, for example, are so tenuously connected to drunk driving that a stop on those grounds alone would be constitutionally suspect. But a reliable tip alleging the dangerous behaviors discussed above generally would justify a traffic stop on suspicion of drunk driving.

The 911 caller in this case reported more than a minor traffic infraction and more than a conclusory allegation of drunk or reckless driving. Instead, she alleged a specific and dangerous result of the driver’s conduct: running another car off the highway. That conduct bears too great a resemblance to paradigmatic manifestations of drunk driving to be dismissed as an isolated example of recklessness. Running another vehicle off the road suggests lane-positioning problems, decreased vigilance, impaired judgment, or some combination of those recognized drunk driving cues. And the experience of many officers suggests that a driver who almost strikes a vehicle or another object—the exact scenario that ordinarily causes “running [another vehicle] off the roadway”—is likely intoxicated. As a result, we cannot say that the officer acted unreasonably under these circumstances in stopping a driver whose alleged conduct was a significant indicator of drunk driving.

III

Like White, this is a “close case.” As in that case, the indicia of the 911 caller’s reliability here are stronger than those in J. L., where we held that a bare-bones tip was unreliable. Although the indicia present here are different from those we found sufficient in White, there is more than one way to demonstrate “a particularized and objective basis for suspecting the particular person stopped of criminal activity.” Under the totality of the circumstances, we find the indicia of reliability in this case sufficient to provide the officer with reasonable suspicion that the driver of the reported vehicle had run another vehicle off the road. That made it reasonable under the circumstances for the officer to execute a traffic stop. We accordingly affirm.

Justice SCALIA, with whom Justice GINSBURG, Justice SOTOMAYOR, and Justice KAGAN join, dissenting.

Law enforcement agencies follow closely our judgments on matters such as this, and they will identify at once our new rule: So long as the caller identifies where the car is, anonymous claims of a single instance of possibly careless or reckless driving, called in to 911, will support a traffic stop. This is not my concept, and I am sure would not be the Framers’, of a people secure from unreasonable searches and seizures. I would reverse the judgment of the Court of Appeal of California.

The California Highway Patrol in this case knew nothing about the tipster on whose word—and that alone—they seized Lorenzo and José Prado Navarette. They did not know her name. They did not know her phone number or address. They did not even know where she called from (she may have dialed in from a neighboring county).

The Court says that “[b]y reporting that she had been run off the road by a specific vehicle … the caller necessarily claimed eyewitness knowledge.” So what? The issue is not how she claimed to know, but whether what she claimed to know was true. The claim to “eyewitness knowledge” of being run off the road supports not at all its veracity; nor does the amazing, mystifying prediction (so far short of what existed in White) that the petitioners’ truck would be heading south on Highway 1.

All that has been said up to now assumes that the anonymous caller made, at least in effect, an accusation of drunken driving. But in fact she did not. She said that the petitioners’ truck “‘[r]an [me] off the roadway.’” That neither asserts that the driver was drunk nor even raises the likelihood that the driver was drunk. The most it conveys is that the truck did some apparently nontypical thing that forced the tipster off the roadway, whether partly or fully, temporarily or permanently. Who really knows what (if anything) happened? The truck might have swerved to avoid an animal, a pothole, or a jaywalking pedestrian.

But let us assume the worst of the many possibilities: that it was a careless, reckless, or even intentional maneuver that forced the tipster off the road. Lorenzo might have been distracted by his use of a hands-free cell phone or distracted by an intense sports argument with Jose. Or, indeed, he might have intentionally forced the tipster off the road because of some personal animus, or hostility to her “Make Love, Not War” bumper sticker. I fail to see how reasonable suspicion of a discrete instance of irregular or hazardous driving generates a reasonable suspicion of ongoing intoxicated driving. What proportion of the hundreds of thousands—perhaps millions—of careless, reckless, or intentional traffic violations committed each day is attributable to drunken drivers? I say 0.1 percent. I have no basis for that except my own guesswork. But unless the Court has some basis in reality to believe that the proportion is many orders of magnitude above that—say 1 in 10 or at least 1 in 20—it has no grounds for its unsupported assertion that the tipster’s report in this case gave rise to a reasonable suspicion of drunken driving.

Bear in mind that that is the only basis for the stop that has been asserted in this litigation. The stop required suspicion of an ongoing crime, not merely suspicion of having run someone off the road earlier. And driving while being a careless or reckless person, unlike driving while being a drunk person, is not an ongoing crime. In other words, in order to stop the petitioners the officers here not only had to assume without basis the accuracy of the anonymous accusation but also had to posit an unlikely reason (drunkenness) for the accused behavior.

In sum, at the moment the police spotted the truck, it was more than merely “possib[le]” that the petitioners were not committing an ongoing traffic crime. It was overwhelmingly likely that they were not.

It gets worse. Not only, it turns out, did the police have no good reason at first to believe that Lorenzo was driving drunk, they had very good reason at last to know that he was not. The Court concludes that the tip, plus confirmation of the truck’s location, produced reasonable suspicion that the truck not only had been but still was barreling dangerously and drunkenly down Highway 1. In fact, alas, it was not, and the officers knew it. They followed the truck for five minutes, presumably to see if it was being operated recklessly. And that was good police work. While the anonymous tip was not enough to support a stop for drunken driving, it was surely enough to counsel observation of the truck to see if it was driven by a drunken driver. But the pesky little detail left out of the Court’s reasonable-suspicion equation is that, for the five minutes that the truck was being followed (five minutes is a long time), Lorenzo’s driving was irreproachable. Had the officers witnessed the petitioners violate a single traffic law, they would have had cause to stop the truck, and this case would not be before us. And not only was the driving irreproachable, but the State offers no evidence to suggest that the petitioners even did anything suspicious, such as suddenly slowing down, pulling off to the side of the road, or turning somewhere to see whether they were being followed. Consequently, the tip’s suggestion of ongoing drunken driving (if it could be deemed to suggest that) not only went uncorroborated; it was affirmatively undermined.

A hypothetical variation on the facts of this case illustrates the point. Suppose an anonymous tipster reports that, while following near mile marker 88 a silver Ford F-150, license plate 8D949925, traveling southbound on Highway 1, she saw in the truck’s open cab several five-foot-tall stacks of what was unmistakably baled cannabis. Two minutes later, a highway patrolman spots the truck exactly where the tip suggested it would be, begins following it, but sees nothing in the truck’s cab. It is not enough to say that the officer’s observation merely failed to corroborate the tipster’s accusation. It is more precise to say that the officer’s observation discredited the informant’s accusation: The crime was supposedly occurring (and would continue to occur) in plain view, but the police saw nothing. Similarly, here, the crime supposedly suggested by the tip was ongoing intoxicated driving, the hallmarks of which are many, readily identifiable, and difficult to conceal. That the officers witnessed nary a minor traffic violation nor any other “sound indici[um] of drunk driving,” strongly suggests that the suspected crime was not occurring after all. The tip’s implication of continuing criminality, already weak, grew even weaker.

Resisting this line of reasoning, the Court curiously asserts that, since drunk drivers who see marked squad cars in their rearview mirrors may evade detection simply by driving “more careful[ly],” the “absence of additional suspicious conduct” is “hardly surprising” and thus largely irrelevant. Whether a drunk driver drives drunkenly, the Court seems to think, is up to him. That is not how I understand the influence of alcohol. I subscribe to the more traditional view that the dangers of intoxicated driving are the intoxicant’s impairing effects on the body—effects that no mere act of the will can resist. Consistent with this view, I take it as a fundamental premise of our intoxicated-driving laws that a driver soused enough to swerve once can be expected to swerve again—and soon. If he does not, and if the only evidence of his first episode of irregular driving is a mere inference from an uncorroborated, vague, and nameless tip, then the Fourth Amendment requires that he be left alone.

The Court’s opinion serves up a freedom-destroying cocktail consisting of two parts patent falsity: (1) that anonymous 911 reports of traffic violations are reliable so long as they correctly identify a car and its location, and (2) that a single instance of careless or reckless driving necessarily supports a reasonable suspicion of drunkenness. All the malevolent 911 caller need do is assert a traffic violation, and the targeted car will be stopped, forcibly if necessary, by the police. If the driver turns out not to be drunk (which will almost always be the case), the caller need fear no consequences, even if 911 knows his identity. After all, he never alleged drunkenness, but merely called in a traffic violation—and on that point his word is as good as his victim’s.

Drunken driving is a serious matter, but so is the loss of our freedom to come and go as we please without police interference. To prevent and detect murder we do not allow searches without probable cause or targeted Terry stops without reasonable suspicion. We should not do so for drunken driving either. After today’s opinion all of us on the road, and not just drug dealers, are at risk of having our freedom of movement curtailed on suspicion of drunkenness, based upon a phone tip, true or false, of a single instance of careless driving. I respectfully dissent.

* * *

This concludes our review of the substantive search and seizure law that the Court has based upon the Fourth Amendment. We turn next to interrogations.

Fourth Amendment Flowchart Exercise

Flowcharts can help students visualize what they have learned. The goal is not to memorize the example chart presented here but instead to create a new chart that helps one to connect material from throughout the book. Your authors recommend that when students make their own charts, they add additional detail, such as case names or chapter numbers. For example, in the box asking whether there was a “search” or “seizure” at all, students might add information related to dog sniffs, aerial surveillance, the open fields doctrine, thermal imaging, garbage collection, and other items included in the early chapters of this book.

In the box asking if there was a valid warrant, students might add information related to the particularity requirement, as well as other sources of challenges to validity.

This chart focuses on the Fourth Amendment. Later in the book, a different sample chart focuses on the Miranda Rule.

These charts have two primary purposes. One is that when the charts are finished, they can serve as study aids. The other is that the creation of the charts—even if students never review them after finishing them—forces students to consider material more carefully than they otherwise might, which helps with learning and with retention of information. Also, fellow students can help spot misunderstandings that, were they not in a chart, would remain uncorrected. Study group members might wish to bring charts to share with classmates.

Note that the “Fourth Amendment violation” box asks students to consider what remedy might be available to the person whose rights were violated. A separate chart devoted to remedies (such as the exclusionary rule) would be worth creating after students cover that material.