No. 00-1519 

In the Supreme Court of the United States 

UNITED STATES OF AMERICA, PETITIONER 

v. 

RALPH ARVIZU 

ON WRIT OF CERTIORARI 
TO THE UNITED STATES COURT OF APPEALS 
FOR THE NINTH CIRCUIT 

BRIEF FOR THE UNITED STATES 

THEODORE B. OLSON 
Solicitor General 

Counsel of Record 

MICHAEL CHERTOFF 

Assistant Attorney General 

MICHAEL R. DREEBEN 

Deputy Solicitor General 

AUSTIN C. SCHLICK 

Assistant to the Solicitor 

General 

DEBORAH WATSON 

Attorney 

Department of Justice 
Washington, D.C. 20530-0001 
(202) 514-2217 

QUESTIONS PRESENTED 

1. Whether the court of appeals erroneously de- 
parted from the totality-of-the-circumstances test that 
governs reasonable-suspicion determinations under the 
Fourth Amendment by holding that seven facts 
observed by a law enforcement officer were entitled to 
no weight and could not be considered as a matter of 
law. 

2. Whether, under the totality-of-the-circumstances 
test, the Border Patrol agent in this case had rea- 
sonable suspicion that justified a stop of a vehicle near 
the Mexican border. 

(I) 

TABLE OF CONTENTS 

Page 

Opinions below ............................................................................... 
1 

Jurisdiction ...................................................................................... 1 

Constitutional provision involved ............................................... 
2 

Statement ........................................................................................ 2 

Summary of argument .................................................................. 
12 

Argument: 

I. The court of appeals erred by categorically 

excluding facts from consideration in the 

totality-of-the-circumstances inquiry ....................... 

15 

A. Reasonable-suspicion analysis requires 

consideration of “the whole picture” seen 

by the officer ......................................................... 

15 

B. The court of appeals’ categorical approach 

to the reasonable-suspicion inquiry is in- 
consistent with this Court’s holdings .............. 

20 

II. The investigative stop in this case was lawful ........ 
31 

Conclusion ....................................................................................... 36 

TABLE OF AUTHORITIES 

Cases: 

Atwater v. City of Lago Vista, 121 S. Ct. 1536 

(2001) ........................................................................................ 24 

Florida v. Bostick, 501 U.S. 429 (1991) .............................. 

26 

INS v. Delgado, 466 U.S. 210 (1984) ................................... 

26 

Illinois v. Gates, 462 U.S. 213 (1983) ....................... 

13, 22, 23 

Illinois v. Wardlow, 528 U.S. 119 (2000) .......... 

19, 20, 25, 34 

Ker v. California, 374 U.S. 23 (1963) ................................. 

23 

Ornelas v. United States, 517 U.S. 690 (1996) ........ 

23, 33, 34 

Spinelli v. United States, 393 U.S. 410 (1969) .................. 

22 

Terry v. Ohio, 392 U.S. 1 (1968) ................... 

15, 16, 25, 31, 35 

United States v. Brignoni-Ponce, 422 U.S. 873 

(1975) ...................................................... 3, 16, 17, 27, 28, 29, 30 

(III) 

IV 

Cases—Continued: Page 

United States v. Cardona, 955 F.2d 976 (5th Cir. 

1992) ......................................................................................... 27 

United States v. Cortez: 

449 U.S. 411 (1981) .......................................................... 

passim 

595 F.2d 505 (9th Cir. 1979) ................................................. 

18 

United States v. Diaz, 977 F.2d 163 (5th Cir. 1992) ........ 

34 

United States v. Garcia, 23 F.3d 1331 (8th Cir. 

1994) ......................................................................................... 30 

United States v. Gonzalez, 190 F.3d 668 (5th Cir. 

1999) ......................................................................................... 28 

United States v. Gordon, 231 F.3d 750 (11th Cir. 

2000) ......................................................................................... 29 

United States v. Guerrero-Barajas, 240 F.3d 428 

(5th Cir. 2001) ....................................................................... 

26-27 

United States v. Leyba, 627 F.2d 1059 (10th Cir.), cert. 

denied, 449 U.S. 987 (1980) .................................................. 

28 

United States v. Lopez-Martinez, 25 F.3d 1481 

(10th Cir. 1994) ................................................................... 

27, 30 

United States v. Magana, 797 F.2d 777 (9th Cir. 

1986) ............................................................................... 

26, 27, 28 

United States v. Martinez-Fuerte, 428 U.S. 543 

(1976) ........................................................................................ 

3, 30 

United States v. Montero-Camargo, 208 F.3d 

1122 (9th Cir.), cert. denied, 121 S. Ct. 211 (2000) ....... 

10, 11, 

21, 22, 28, 29, 30 
United States v. Montoya de Hernandez, 473 U.S. 

531 (1985) ................................................................................. 

30 

United States v. Morrison, 2001 WL 687624 (7th Cir. 

June 20, 2001) ......................................................................... 

30 

United States v. Orozco, 191 F.3d 578 (5th Cir. 

1999) ......................................................................................... 27 

United States v. Pulido-Santoyo, 580 F.2d 352 

(9th Cir.), cert. denied, 439 U.S. 915 (1978) ...................... 

29 

United States v. Sarduy, 590 F.2d 1355 (5th Cir. 

1979) ......................................................................................... 28 

United States v. Sharpe, 470 U.S. 675 (1985) ................... 27 

V 

Cases—Continued: Page 

United States v. Sigmond-Ballesteros, 247 F.3d 

943 (9th Cir. 2001) .............................................................. 

21, 29 

United States v. Sokolow: 

490 U.S. 1 (1989) ............................................................... 

passim 

831 F.2d 1413 (9th Cir. 1987) ............................................... 

19 

United States v. Tate, 648 F.2d 939 (4th Cir. 1981) .......... 

29 

United States v. Villalobos, 161 F.3d 285 (5th Cir. 

1998) ......................................................................................... 26 

Whren v. United States, 517 U.S. 806 (1996) .................... 

30 

Constitution and statutes: 

U.S. Const. Amend. IV ............................ 

2, 13, 15, 16, 23, 30, 35 

21 U.S.C. 841(a)(1) .................................................................... 

2 

21 U.S.C. 841(b)(1)(C) .............................................................. 2 

In the Supreme Court of the United States 

No. 00-1519 

UNITED STATES OF AMERICA, PETITIONER 

v. 

RALPH ARVIZU 

ON WRIT OF CERTIORARI 
TO THE UNITED STATES COURT OF APPEALS 
FOR THE NINTH CIRCUIT 

BRIEF FOR THE UNITED STATES 

OPINIONS BELOW 

The opinion of the court of appeals, as amended (Pet. 
App. 1a-20a) is reported at 232 F.3d 1241. The oral 
decision of the district court (Pet. App. 21a-27a) is 
unreported. 

JURISDICTION 

The judgment of the court of appeals was entered on 
July 7, 2000. A petition for rehearing was denied on 
December 1, 2000 (Pet. App. 3a). On February 16, 2001, 
Justice O’Connor extended the time within which to file 
a petition for a writ of certiorari to and including March 
31, 2001 (a Saturday). The petition was filed on April 2, 
2001, and was granted on June 4, 2001. The jurisdiction 
of this Court rests on 28 U.S.C. 1254(1). 

(1) 

2 

CONSTITUTIONAL PROVISION INVOLVED 

The Fourth Amendment to the Constitution of the 
United States provides in pertinent part: 

The right of the people to be secure in their per- 
sons, houses, papers, and effects, against unrea- 
sonable searches and seizures, shall not be violated 

* * * . 

STATEMENT 

Following the denial of his motion to suppress 
evidence in the district court, respondent entered a 
conditional plea of guilty to the charge of possessing 
marijuana with intent to distribute it, in violation of 21 
U.S.C. 841(a)(1) and (b)(1)(C). Pet. App. 8a; J.A. 11. 
Respondent was sentenced to ten months’ imprison- 
ment, to be followed by 36 months’ supervised release. 
J.A. 12. The court of appeals reversed. Pet. App. 1a- 
20a. 

1. In January 1998, Border Patrol Agent Clinton 
Stoddard was assigned to the permanent Border Patrol 
checkpoint at the intersection of Highway I-191 and 
Rucker Canyon Road, north of the border town of 
Douglas, Arizona. Pet. App. 4a-5a.1 The I-191 check- 
point is approximately 30 miles from the Mexican 
border. Id. at 4a; J.A. 24; see also J.A. 155, 157 (maps). 
The Border Patrol opens and closes the checkpoint 
without notice, but when opened, the checkpoint re- 
mains open for weeks or months at a time. J.A. 50. As 
part of its effort to prevent illegal aliens who have 
crossed the international border in Arizona from 

1 The facts were adduced at a hearing on respondent’s motion 
to suppress evidence, at which the district court took testimony 
from the arresting officer, a defense investigator, respondent, and 
respondent’s sister, and heard oral argument. See J.A. 15-154. 

3 

passing further into the United States, the Border 
Patrol stops all traffic that passes through the 
checkpoint when it is open. J.A. 20.2 

Agent Stoddard had been assigned to the Border 
Patrol’s Douglas station for more than two years. J.A. 

18. He had received training on detecting illegal-alien 
and narcotics smuggling, and on smuggling activity in 
the Douglas area. J.A. 19-20. Agent Stoddard also had 
trained other agents on smuggling detection tech- 
niques. J.A. 20. Agent Stoddard estimated that while 
working on “roving patrols,” he had stopped more than 
50 vehicles carrying illegal aliens or drugs. J.A. 22. 

On January 19, 1998, the I-191 checkpoint was open 
and conducting vehicle inspections. At approximately 
2:15 p.m., a sensor monitored by the Border Patrol 
detected a vehicle traveling north on Leslie Canyon 
Road. Pet. App. 4a-5a; J.A. 24-25, 28. Leslie Canyon 
Road begins near the border in Douglas and parallels 
both I-191, which is to the west, and the boundary of 
the Coronado National Forest, which is to the east. 

2 This Court has recognized the “formidable law-enforcement 
problems” associated with illegal immigration from Mexico, United 
States v. Martinez-Fuerte, 428 U.S. 543, 553 (1976), as well as “the 
enormous difficulties of patrolling a 2,000-mile open border and the 
patient skills needed by those charged with halting illegal entry 
into this country,” United States v. Cortez, 449 U.S. 411, 418-419 
(1981). To carry out its mission of enforcing the immigration and 
narcotics laws, the Border Patrol relies heavily on its power to 
inspect vehicles at fixed checkpoints in the vicinity of the border, 
and to make those checkpoints effective by stopping suspicious 
vehicles that circumvent them. See United States v. Brignoni- 
Ponce, 422 U.S. 873, 879 (1975); Martinez-Fuerte, supra (upholding 
against Fourth Amendment challenge the use of fixed immigration 
checkpoints removed from the border). 

4 

Pet. App. 4a; see J.A. 25-26, 155, 157.3 A vehicle travel- 
ing north from Douglas can use Leslie Canyon Road to 
bypass the Border Patrol checkpoint on I-191. Pet. 
App. 5a; J.A. 26-27. Like most of Leslie Canyon Road, 
the portion of road where the sensor is located is 
unpaved dirt. Pet. App. 4a; J.A. 27-28, 98-99; see also 
J.A. 161, 165-171 (respondent’s photographs of Leslie 
Canyon Road). That portion of Leslie Canyon Road is 
used mostly by ranchers, Forest Service personnel, and 
the Border Patrol. Pet. App. 4a; J.A. 26. On a typical 
day, vehicles trigger the sensor only once every two 
hours or so. J.A. 57. As Agent Stoddard testified, 
“[y]ou can sit on that road for hours and not see a 
vehicle go by.” J .A. 28. 

The fact that the sensor gave an alert at about 2:15 

p.m. was significant because that was approximately 
the time when the agents who patrolled the area 
around the I-191 checkpoint suspended their surveil- 
lance and began returning to the checkpoint for a 3 p.m. 
shift change. Pet. App. 5a; J.A. 26, 47-48. As Agent 
Stoddard testified, smugglers are aware of the Border 
Patrol’s shift changes and they “seem to do the most 
smuggling * * * when the agents are en route back to 
the checkpoint.” J.A. 26. 

Agent Stoddard left the I-191 checkpoint and drove 
east on Rucker Canyon Road, toward Leslie Canyon 
Road, to investigate the sensor report. As he drove, a 
second sensor located north of the first sensor reported 
traffic, indicating that the vehicle had turned west on 
Rucker Canyon Road and was coming toward Stoddard 
and I-191. Pet. App. 5a; J.A. 29. The vehicle was now 

3 The court of appeals incorrectly stated (Pet. App. 4a) that 
Leslie Canyon Road is in the Coronado National Forest. In fact, 
the road is entirely outside the national forest. See J.A. 155, 157. 

5 

headed away from recreation areas in the national 
forest, which can be reached by driving east on Rucker 
Canyon Road. J.A. 29, 31, 52-54; see J.A. 155. If the 
vehicle next turned right (north) onto Kuykendall 
Cutoff Road, it would circumvent the I-191 checkpoint 
and could proceed to cities such as Tucson and Phoenix 
with very little chance of being stopped by the Border 
Patrol. That route along dirt roads (north on Leslie 
Canyon Road paralleling I-191, west on Rucker Canyon 
Road away from the national forest, and then north on 
Kuykendall Cutoff Road before reaching the I-191 
checkpoint) “is a notorious route of travel” that illegal 
aliens and drug traffickers use to avoid the checkpoint. 
J.A. 30. 

As Agent Stoddard drove east on Rucker Canyon 
Road to intercept the vehicle coming west, he spotted a 
minivan. Based on the minivan’s westbound direction, 
the timing of the sensor alarms, and the absence of any 
other traffic, Stoddard believed that the minivan was 
the vehicle that had tripped the sensors. J.A. 31-32. 
Stoddard pulled his truck to the side of the road so that 
he could get a good look at the minivan when it passed. 
Pet. App. 5a; J.A. 32. Agent Stoddard testified that, 
when the minivan approached the parked Border Patrol 
vehicle (which was equipped with official lights, see J.A. 
107), it slowed dramatically, cutting its speed from 
approximately 50 to 55 miles per hour to approximately 
25 to 30 miles per hour. Pet. App. 6a; J.A. 32, 57.4 

Agent Stoddard saw five people in the minivan. 
Respondent was driving, an adult woman was in the 
front seat, and three children were in the back seats. 
Agent Stoddard observed that respondent appeared 

4 Respondent testified that he was traveling at “[a]bout 20 to 
30 miles an hour” and did not slow down abruptly. J.A. 105. 

6 

rigid and nervous. He gripped the steering wheel 
tightly and avoided eye contact with Stoddard. Pet. 
App. 6a; J.A. 33.5 The adult passenger also appeared to 
Stoddard to be “uptight.” J.A. 33-34. The two children 
in the rear seat sat with their knees unusually high, as 
if their feet were resting on top of an object on the floor 
of the vehicle. Pet. App. 6a; J.A. 34. 

Agent Stoddard was familiar with the local vehicles 
in the area, but he did not recognize the minivan. Pet. 
App. 7a; J.A. 37. The minivan also was noteworthy 
because most drivers on the dirt roads that respondent 
traveled use four-wheel drive vehicles. J.A. 36, 63-64. 
Indeed, at the intersection of Leslie Canyon Road and 
Rucker Canyon Road, Rucker Canyon Road is signed: 
“PRIMITIVE ROAD DRIVE WITH CARE.” J.A. 83, 
171. The Border Patrol had discovered a minivan 
smuggling marijuana in the same area a few weeks 
earlier, and Stoddard knew from personal experience 
and the experience of other agents that smugglers com- 
monly use minivans to carry illegal aliens and drugs. 
J.A. 27, 33, 74. 

Agent Stoddard followed the minivan. All three 
children in the van then began waving simultaneously, 
on and off, for about five minutes while facing forward, 
without ever turning around to look at Stoddard. Pet. 
App. 6a; J.A. 35-36, 61, 73. Agent Stoddard testified 
that the waving—which he demonstrated to the district 
court—“wasn’t in a normal pattern.” J.A. 35. He 

5 The district court rejected as not credible respondent’s asser- 
tion that he was relaxed when he saw the Border Patrol vehicle. “I 
find it very difficult to believe,” the district court stated, “that 
somebody carrying 125 * * * pounds of marijuana in their vehicle 
is going to be relaxed when they see a law enforcement officer.” 
Pet. App. 24a. 

7 

suspected that the waving was being choreographed by 
the adults. J.A. 35, 61. 

After turning his blinker on, then off, then on again, 
respondent abruptly turned north onto Kuykendall 
Cutoff Road, the final turn on the route that would 
bypass the I-191 checkpoint. Pet. App. 6a; J.A. 36; see 
also J.A. 106. Around that time, Stoddard ran a license 
check and learned that the vehicle was registered to an 
address in Douglas. Stoddard recognized the address 
as being just four blocks north of the Mexican border, 
on a street that smugglers frequently used as a staging 
area for transporting illegal aliens and narcotics further 
into the United States. Pet. App. 7a; J.A. 37-38, 65-67. 

Agent Stoddard stopped the minivan. Respondent 
leaned out of the driver’s window and greeted Stoddard 
in an excited tone of voice. When Agent Stoddard 
asked where respondent was going, respondent said he 
was headed to a park, but he could not remember its 
name.6 Stoddard observed that respondent’s hands 
were shaking and his forehead was sweaty, even 
though it was a cool January day. Pet. App. 7a; J.A. 38- 

43. After asking respondent some questions about his 
immigration status and cargo, Stoddard asked for and 
received consent to search the vehicle. Pet. App. 7a-8a, 
25a-26a; J.A. 43-44.7 Agent Stoddard then opened the 
side door, smelled marijuana, and saw a black duffel bag 

6 Respondent testified at the suppression hearing that he was 
going to a location known as Turkey Creek “to meet up with a 
gentleman” whom he did not know, who would be driving a Ford 
pickup truck. J.A. 116-117. 

7 Although respondent testified that he understood Agent 
Stoddard only to be seeking permission “[t]o look in” the van, J.A. 
112-113, the district court found that “[t]here is no lack of clarity or 
uncertainty that the agent was asking to search the vehicle if 
[respondent] consented to that.” Pet. App. 26a; see also id. at 20a. 

8 

under the feet of the two children in the back seat of the 
vehicle. Pet. App. 8a; J.A. 44-45. Respondent con- 
sented to a search of the duffel bag, whereupon 
Stoddard discovered marijuana wrapped in cellophane. 
Border Patrol agents later found another bag of mari- 
juana behind the rear seat. J.A. 45-46. The marijuana 
found in the minivan weighed 123.85 pounds and had an 
estimated value of $99,080. Crim. Compl.; 1/19/98 U.S. 
Border Patrol Report of Apprehension or Seizure. 

2. Respondent moved to suppress the marijuana on 
the ground that Agent Stoddard lacked reasonable 
suspicion to stop the minivan and lacked authority to 
search it. After taking testimony and hearing argu- 
ment on the motion, see J.A. 15-154, the district court 
ruled that Agent Stoddard had reasonable suspicion to 
stop the minivan, Pet. App. 21a-27a. Stating that the 
evidence had to be considered “in the context of what 
was going on out there and in the context of the 
information available to the officer making the stop,” id. 
at 22a, the district court identified ten specific facts that 
supported Stoddard’s suspicion of illegal activity: 

(1) The minivan was on “poorly traveled” roads 
that parallel the interstate highway and are “used to 
circumvent the checkpoint” on I-191. Pet. App. 22a- 
23a; see also id. at 23a (Leslie Canyon Road “cer- 
tainly isn’t a heavily traveled road by any stretch of 
the imagination.”). 

(2) The minivan had passed the only recreation 
area in the vicinity (which was to the east, off 
Rucker Canyon Road), and the next recreation area 
was “quite a few miles to the north,” at the 
Chiricahua National Monument. Pet. App. 22a. The 
distant recreation area was accessible by taking 

9 

I-191 to I-181, which would avoid having to make a 
“40-mile trip at least, through a dirt road.” Ibid. 

(3) The minivan appeared to “slow[] down appre- 
ciably” when respondent saw the parked Border 
Patrol vehicle. Pet. App. 23a. 

(4) The minivan’s trip coincided with the 
beginning of the Border Patrol’s shift change, when 
agents return to the I-191 checkpoint and leave the 
area open to smugglers. Pet. App. 23a. 

(5) In Agent Stoddard’s experience, smugglers 
in the Douglas area use minivans; also, the Border 
Patrol had recently stopped a similar minivan 
carrying a load of marijuana in the same area. Pet. 
App. 23a-24a. 

(6) Respondent appeared nervous when he drove 
past Agent Stoddard and respondent’s demeanor 
was consistent with illegal activity. Pet. App. 24a. 

(7) Stoddard, having worked in the area, did not 
recognize the minivan as being from one of the local 
ranches. Pet. App. 24a. 

(8) The raised position of the children’s legs 
suggested that there was cargo on the rear floor of 
the minivan. Pet. App. 24a-25a. 

(9) The children waved in a “methodical,” “me- 
chanical way” for four or five minutes without 
looking at Agent Stoddard, which “was a fact that is 
odd and would certainly lead a reasonable officer to 
wonder why are they doing this.” Pet. App. 25a. 

10 

(10) The minivan was registered to an area that 
Agent Stoddard “kn[e]w to be an often-used 
smuggling area.” Pet. App. 25a. 

On the basis of those ten factors, collectively, the dis- 
trict court found that Agent Stoddard had reasonable 
suspicion to stop the minivan. Pet. App. 25a. The 
district court further found that respondent consented 
to the search of his minivan and duffel bag without any 
coercion by Stoddard, and that, in any event, Stoddard 
had probable cause to search the bags after he smelled 
marijuana. Id. at 25a-26a. 

3. The court of appeals reversed.8 It recited estab- 
lished standards for determining whether reasonable 
suspicion exists, see Pet. App. 8a-11a, but indicated 
concern that the “fact-specific weighing of circum- 
stances” required by these standards “introduces a 
troubling degree of uncertainty and unpredictability 
into the process” of determining whether reasonable 
suspicion exists. Id. at 12a (quoting United States v. 
Montero-Camargo, 208 F.3d 1122, 1142 (9th Cir.) (en 
banc) (Kozinski, J., concurring), cert. denied, 121 S. Ct. 
211 (2000)). Accordingly, the court of appeals was of 
the view that “[w]hat factors law enforcement officers 
may consider in deciding to stop and question citizens 
minding their own business should, if possible, be 
carefully circumscribed and clearly articulated.” Id. at 
11a (quoting Montero-Camargo, 208 F.3d at 1142 
(Kozinski, J., concurring)). To that end, the court stated 
that it intended to use this case “to describe and clearly 

8 The court of appeals issued its initial opinion on July 7, 2000. 
On December 1, 2000, the court revised its opinion and, based on 
the amended opinion, denied the government’s petition for rehear- 
ing or rehearing en banc. See Pet. App. 1a-20a. The changes made 
to the initial opinion are identified at Pet. App. 2a-3a. 

11 

delimit the extent to which certain factors may be 
considered by law enforcement officers in making stops 
such as the stop involved here.” Id. at 12a. 

Specifically, the court of appeals held that the district 
court had improperly relied on seven factors that were 
“neither relevant nor appropriate to a reasonable 
suspicion analysis in this case,” Pet. App. 12a, and 
“must be disregarded as a matter of law,” id. at 14a 
(quoting Montero-Camargo, 208 F.3d at 1132). First, 
the court held, “slowing down after spotting a law 
enforcement vehicle is an entirely normal response that 
is in no way indicative of criminal activity” and cannot 
contribute to reasonable suspicion of unlawful activity. 
Id. at 12a. Second, respondent’s failure to acknowledge 
Agent Stoddard as he drove by the officer “provides no 
support for Stoddard’s reasonable suspicion determina- 
tion.” Id. at 13a. Third, the children’s “odd act” of 
waving to Agent Stoddard without looking at him 
“carries no weight in the reasonable suspicion calculus.” 
Id. at 13a-14a. Fourth, the court continued, “[t]he fact 
that one minivan stopped in the past month on the same 
road contained marijuana is insufficient to taint all 
minivans with suspicion.” Id. at 14a. Fifth, Agent 
Stoddard’s failure to recognize the minivan as a local 
vehicle “fails to contribute to the reasonable suspicion 
calculus” because “the area in question is one that is 
used for many purposes by different kinds of people.” 
Ibid. Sixth, the fact that the minivan was “registered 
to an address in a block notorious for smuggling is also 
of no significance and may not be given any weight.” 
Id. at 15a. Seventh, and finally, the court ruled that the 
appearance that there was cargo on the floor of the 
minivan, “while consistent with [carrying] illicit sub- 
stances,” was “all too common to be of any relevance.” 
Id. at 16a-17a. 

12 

The court of appeals deemed only three factors 
relevant to reasonable suspicion analysis: the road used 
by the minivan was sometimes used by smugglers; the 
minivan was traveling around the time of the Border 
Patrol’s shift change; and, as a general matter, smug- 
glers sometimes use minivans. Pet. App. 17a. The 
court of appeals concluded that those three factors, 
considered in isolation from the other seven factors that 
it deemed irrelevant, did not “constitute reasonable 
suspicion either singly or collectively.” Ibid. The route 
taken by respondent, in the view of the court, was “of 
only moderate significance” because “the road in 
question is used for a number of entirely innocuous 
purposes.” Id. at 17a-18a. The shift change, the court 
concluded, “is of little probative value” because the 
minivan tripped the first sensor approximately 45 min- 
utes before the shift change. Id. at 18a. And minivans, 
the court stated, “although sometimes used by smug- 
glers, are among the best-selling family car models in 
the United States.” Ibid. 

Based on that analysis, the court of appeals held that 
Agent Stoddard’s stop of respondent’s minivan was 
unlawful and that the unlawful stop tainted respon- 
dent’s consent to the search of his vehicle. Pet. App. 
18a-19a. The court of appeals therefore reversed the 
district court’s denial of respondent’s motion to sup- 
press evidence and remanded the case. Id. at 20a. 

SUMMARY OF ARGUMENT 

1. This Court has held repeatedly and consistently, 
over the course of more than 30 years, that reasonable- 
suspicion analysis requires examination of all the facts 
known to the law-enforcement officer who makes an 
investigative stop. Because courts must consider “the 
whole picture” seen by the officer, United States v. 

13 

Cortez, 449 U.S. 411, 417 (1981), conduct that is ambigu- 
ous and susceptible of an innocent explanation when 
viewed in isolation can nevertheless support reasonable 
suspicion. 

The court of appeals suggested that contextual 
application of the Fourth Amendment’s reasonableness 
standard, as required by this Court, makes it too 
uncertain whether particular conduct will or will not 
support an investigative stop. Reasonable suspicion, 
however, is a commonsense concept rather than a 
technical one, and it is not susceptible to expression in 
“a neat set of legal rules.” United States v. Sokolow, 490 
U.S. 1, 7 (1989) (quoting Illinois v. Gates, 462 U.S. 213, 
232 (1983)). Because reasonable suspicion is inherently 
contextual, rules of the sort adopted by the court of 
appeals—which broadly address particular facts with- 
out regard for context—create the potential for 
misapplication of the Fourth Amendment. If those 
rules were made more specific in an effort to minimize 
constitutional error, they would be too numerous and 
too complicated for officers to apply when they make 
the split-second decision whether to stop an individual 
for questioning. This Court’s contextual approach 
therefore is more faithful to the text of the Fourth 
Amendment, as well as more responsive to the practical 
requirements of law enforcement, than the court of 
appeals’ categorical rules. 

The specific rules adopted by the court of appeals are 
plainly incorrect. The court of appeals held, for exam- 
ple, that some types of conduct, such as decelerating 
upon seeing a law-enforcement vehicle and carrying 
cargo on the floor of a family minivan, are nearly always 
innocent and cannot contribute to reasonable suspicion. 
Yet under any number of scenarios—including the facts 
of this case—those actions do raise objectively reason- 

14 

able questions about possible illegal conduct. An 
individual’s reaction upon seeing a law enforcement 
officer, which the court of appeals also deemed irrele- 
vant as a matter of law, likewise can suggest possible 
criminal activity under some circumstances. The same 
is true of the address to which an individual’s vehicle is 
registered, which the court of appeals excluded from 
consideration as a matter of law. In each instance, the 
court of appeals’ rule requiring exclusion of the factor 
sweeps far too broadly and contravenes the totality-of- 
the-circumstances approach. 

2. When all of the facts are considered, reasonable 
suspicion supported Agent Stoddard’s decision to stop 
respondent and question him. Respondent’s route 
bypassed the fixed Border Patrol checkpoint on I-191, 
and none of the information available to Agent 
Stoddard provided an innocent explanation for respon- 
dent’s choice of that route; it was a time of day when 
smugglers increase their activity because of the Border 
Patrol’s shift change; respondent appeared to be carry- 
ing a large amount of hidden cargo; the minivan’s 
registration suggested that respondent’s northbound 
trip had begun on a street that was very close to the 
Mexican border and was known as a common starting 
point for smuggling runs; smugglers in the Douglas 
area had used minivans in the same area in the recent 
past; and respondent and his passengers appeared 
nervous and behaved oddly upon seeing Agent 
Stoddard’s Border Patrol vehicle. Each of those facts 
reinforced the others, and together they made it 
objectively reasonable for Agent Stoddard to suspect 
that respondent was carrying illegal cargo. 

15 

ARGUMENT 

I. THE COURT OF APPEALS ERRED BY CATEGORI- 
CALLY EXCLUDING FACTS FROM CONSIDERA- 
TION IN THE TOTALITY-OF-THE-CIRCUM- 
STANCES INQUIRY 

This Court has held repeatedly that the Fourth 
Amendment requires courts to consider the totality of 
the circumstances surrounding a law-enforcement 
officer’s decision to make an investigative stop. The 
significance of a particular fact must be determined in 
the context of the other facts known to the officer, and 
cannot be established for all cases on a categorical basis. 
That rule is consistent not only with the reasonableness 
standard of the Fourth Amendment, but also with the 
practical realities of law enforcement. 

A. Reasonable-Suspicion Analysis Requires Con- 
sideration Of “The Whole Picture” Seen By The 

Officer 

In Terry v. Ohio, 392 U.S. 1 (1968), this Court made 
clear that the reasonableness of a law-enforcement 
officer’s suspicion must be judged by considering the 
totality of the circumstances known to the officer, and 
facts that do not inherently suggest criminal activity 
may, in context, support such an inference by the 
officer. In Terry, a police officer on his beat observed 
two men taking turns walking past a store window and 
repeatedly conferring with each other and with a third 
man. Suspecting that the men were “casing” the store 
for “a stick-up,” the officer approached the three men, 
identified himself as a police officer, and asked for their 
names. Id. at 6-7. After getting no clear response, the 
officer grabbed and patted down one of the men 
(Terry), and felt a pistol. The officer then ordered all 

16 

three men into a store, patted down Terry’s 
companions, found another gun, and took all three men 
into custody. Id. at 7. Terry was charged with carrying 
a concealed weapon, and the state courts denied his 
ensuing motion to suppress the evidence. Id. at 7-8. 

This Court held that the officer “seized” Terry for 
Fourth Amendment purposes when he took hold of him, 
392 U.S. at 16-19, but that the stop to investigate 
possibly criminal activity was not as intrusive as an 
arrest and did not have to be justified by probable 
cause, id. at 20-23. The governing constitutional princi- 
ple was that the seizure (and the ensuing search for 
weapons) may not be “unreasonable,” id. at 9, 20; see 
U.S. Const. Amend. IV, which turns on “the facts of the 
case,” 392 U.S. at 15; see id. at 21 (“a judge * * * must 
evaluate the reasonableness of a particular search or 
seizure in light of the particular circumstances”). 
Specifically, “the police officer must be able to point to 
specific and articulable facts” available to the officer at 
the moment of the seizure “which, taken together with 
rational inferences from those facts, reasonably war- 
rant th[e] intrusion.” Id. at 21. Applying that standard, 
the Court found it immaterial that the visible acts of 
Terry and his companions—standing on a street corner, 
walking up and down a street, looking in a store win- 
dow, and conversing—might “each [be] perhaps inno- 
cent in itself.” Id. at 22. When “taken together,” those 
acts “warranted further investigation” and justified the 
initial stop of Terry. Id. at 22-23. 

In United States v. Brignoni-Ponce, 422 U.S. 873 
(1975), the Court applied Terry’s reasonable-suspicion 
test, including the totality-of-the-circumstances ap- 
proach, to an investigative stop of a car near the 
Mexican border. Id. at 878-885. “[W]hen an officer’s 
observations lead him reasonably to suspect that a 

17 

particular vehicle may contain aliens who are illegally in 
the country,” the Court held, “he may stop the car 
briefly and investigate the circumstances that provoke 
suspicion.” Id. at 881. The Court listed “illustrative” 
factors that may be taken into account when deciding 
whether reasonable suspicion exists to stop a vehicle 
near the Mexican border. Id. at 884-885 & n.10.9 The 
Court stressed, however, that “[e]ach case must turn on 
the totality of the particular circumstances.” Id. at 885 

n.10. “In all situations,” moreover, “the officer is 
entitled to assess the facts in light of his experience in 
detecting illegal entry and smuggling.” Id. at 885. 
Since Terry, this Court has rejected holdings by 
lower courts that have attempted to limit the range of 
facts that officers may consider in making investigative 
stops. In United States v. Cortez, 449 U.S. 411 (1981), 
for example, Border Patrol agents predicted from signs 
of past smuggling activity that a vehicle would pick up 
a group of illegal aliens at a particular point along a 
highway in southern Arizona, on a certain night. Id. at 
413-415. The agents staked out the highway and 
observed a pickup truck with a camper shell drive 
toward the predicted pick-up location, and then return 
after a period of time that correlated with the round- 
trip distance to the expected pick-up point. The agents 
stopped the truck and found illegal aliens. Id. at 415- 

9 Those factors are: (1) the characteristics of the area where 
the vehicle is traveling, such as “[i]ts proximity to the border, the 
usual patterns of traffic on the particular road, and previous 
experience with alien traffic;” (2) information about recent illegal 
border crossings; (3) the driver’s behavior, such as “erratic driving 
or obvious attempts to evade officers;” (4) “[a]spects of the vehicle 
itself,” such as its capacity to hold concealed cargo or signs that the 
vehicle is heavily loaded; and (5) personal characteristics or dress 
suggesting Mexican nationality. 422 U.S. at 884-885. 

18 

416. The Ninth Circuit reversed the ensuing convic- 
tions, holding that the reasonable suspicion test 
required “something * * * in the activities of the 
person being observed or in his surroundings that 
affirmatively suggests particular criminal activity,” 
and that the stop was invalid because the truck’s trip 
down the highway and back was consistent with 
“innocent inferences.” United States v. Cortez, 595 F.2d 
505, 508 (9th Cir. 1979). 

This Court reversed. In finding that the stop was 
supported by reasonable suspicion, the Court explained 
that “the essence” of the reasonable suspicion test “is 
that the totality of the circumstances—the whole 
picture—must be taken into account.” 449 U.S. at 417. 
The Court made clear that the question is not, as the 
Ninth Circuit had suggested, whether some specific fact 
“affirmatively suggests particular criminal activity,” 
595 F.2d at 508 (emphasis omitted), but “whether, 
based upon the whole picture, [the officers] could rea- 
sonably surmise that the particular vehicle they 
stopped was engaged in criminal activity,” 449 U.S. at 
421-422. 

Six years later, in United States v. Sokolow, 490 U.S. 
1 (1989), the Court again reviewed an attempt by the 
Ninth Circuit to depart from the totality-of-the-circum- 
stances approach. In Sokolow, federal agents stopped 
an airline passenger on suspicion of being a drug 
courier, primarily because of six facts: the passenger 
paid for his tickets with cash; he traveled under a name 
that did not match the listing for the telephone number 
he gave; he flew from Hawaii to Miami (a source city for 
narcotics) and back; he stayed in Miami only 48 hours, 
despite the long trip; he appeared nervous; and he did 
not check his luggage. Id. at 3-5. The agents found 
drugs after a drug-sniffing dog alerted on the passen- 

19 

ger’s bag, and the district court denied a motion to 
suppress the evidence. Id. at 5-6. 

The court of appeals reversed. It held that facts 
bearing on reasonable suspicion are appropriately di- 
vided into two categories: “facts describing ‘ongoing 
criminal activity,’ ” and “facts describing ‘personal 
characteristics’ of drug couriers.” 490 U.S. at 6 (quoting 
United States v. Sokolow, 831 F.2d 1413, 1419, 1420 (9th 
Cir. 1987)). In the court of appeals’ view, personal 
characteristics are relevant to reasonable suspicion only 
if (1) they are accompanied by evidence of ongoing 
criminal activity, and (2) the government shows “that 
the combination of facts at issue d[oes] not describe the 
behavior of ‘significant numbers of innocent persons.’ ” 
Ibid. (quoting 831 F.2d at 1420). Applying that test, the 
court of appeals found no evidence of ongoing criminal 
activity and held the stop of Sokolow unconstitutional. 
Ibid. 

This Court rejected the Ninth Circuit’s “effort to 
refine and elaborate the requirements of ‘reasonable 
suspicion,’ ” noting that it created “unnecessary diffi- 
culty.” 490 U.S. at 7-8. Under the correct analysis, it is 
not possible to attach “ironclad significance” to particu- 
lar factors as evidence of ongoing criminal activity 
under all circumstances, but neither can other factors 
be dismissed as “consistent with innocent travel,” with- 
out reference to the surrounding facts. Id. at 8-9. 
Applying those principles, the Court held that the 
federal agents had sufficient grounds to stop the airline 
passenger. Id. at 8-11. 

Most recently, in Illinois v. Wardlow, 528 U.S. 119 
(2000), the Court once again considered whether lawful 
conduct that is “ambiguous and susceptible of an 
innocent explanation” can nevertheless contribute to 
reasonable suspicion. Id. at 125. Wardlow involved a 

20 

stop of a suspect who fled at the sight of police entering 
an area. The Court rejected the holding of the Illinois 
Supreme Court that running from police must be 
considered innocent as a matter of law, see id. at 122- 
123, and noted that an officer may give weight to 
ambiguous conduct when making “commonsense judg- 
ments and inferences” about the likelihood that illegal 
activity is occurring, id. at 125 (citing Cortez, 449 U.S. 
at 418). Thus, an individual’s presence in a high-crime 
area—although it would not alone provide reasonable 
suspicion—may be considered in reasonable-suspicion 
analysis. Ibid. So too, Wardlow’s unprovoked flight 
from the police was cognizable in accordance with the 
general rule “that nervous, evasive behavior is a 
pertinent factor in determining reasonable suspicion.” 
Id. at 124. 

B. The Court Of Appeals’ Categorical Approach To 

The Reasonable-Suspicion Inquiry Is Inconsistent 

With This Court’s Holdings 

Notwithstanding this Court’s consistent instruction, 
the Ninth Circuit held in this case that the reasonable- 
suspicion inquiry does not allow consideration of all the 
circumstances known to the investigating officer. In 
“attempt[ing] * * * to describe and clearly delimit the 
extent to which certain factors may be considered by 
law enforcement officers in making stops,” Pet. App. 
12a, the court of appeals articulated precisely the sort 
of inflexible legal rules that are neither useful nor 
permissible under the rubric of reasonable suspicion. 
See Sokolow, 490 U.S. at 7-8. By ruling that “some of 
the factors on which the district court relied are neither 
relevant nor appropriate to a reasonable suspicion 
analysis in this case” (Pet. App. 12a), moreover, the 
court of appeals ignored “the essence of all that has 

21 

been written.” Cortez, 449 U.S. at 417. That is, “the 
totality of the circumstances—the whole picture—must 
be taken into account.” Ibid. 

1. The court of appeals forthrightly stated its intent 
to “delimit the extent to which certain factors may be 
considered by law enforcement officers in making stops 
such as the stop involved here.” Pet. App. 12a. Con- 
sistent with that intent, the court eliminated seven 
different facts observed by Agent Stoddard from the 
reasonable-suspicion calculus “as a matter of law,” id. at 
14a (internal quotation marks omitted), without limiting 
its exclusions to this one case. See id. at 12a-17a. In 
United States v. Sigmond-Ballesteros, 247 F.3d 943 (9th 
Cir. 2001), moreover, the court of appeals cited its 
decision in this case for the proposition “that only 
‘certain factors may be considered by law enforcement 
officers in making stops’ ” of traffic near the border. Id. 
at 947 (quoting Pet. App. 12a). Such a rule is unequivo- 
cally foreclosed by this Court’s totality-of-the-circum- 
stances test. 

2. The court of appeals suggested that the totality- 
of-the-circumstances test should be limited because, 
otherwise, “no one can be sure whether a particular 
combination of factors will justify a stop until a court 
has ruled on it.” 

10 Pet. App. 12a. This Court has 

10 Although the court of appeals here quoted from Judge 
Kozinski’s concurrence in United States v. Montero-Camargo, 208 
F.3d 1122, 1140, 1142 (9th Cir.) (en banc), cert. denied, 121 S. Ct. 
211 (2000), Judge Kozinski did not suggest that certain facts 
indicating criminal activity should be disregarded. Judge 
Kozinski’s principal point was that a single factor known to a law 
enforcement officer (such as turning one’s car around just short of 
a Border Patrol checkpoint) may alone provide reasonable suspi- 
cion, making it unnecessary to consider other, supporting 
considerations. Id. at 1140-1142. Judge Kozinski additionally 

22 

already rejected that reasoning. In Cortez, the Court 
acknowledged that “[t]erms like ‘articulable reasons’ 
and ‘founded suspicion’ * * * fall short of providing 
clear guidance dispositive of the myriad factual situa- 
tions that arise,” 449 U.S. at 417, but concluded that 
“common-sense conclusions about human behavior 

* * * by those versed in the field of law enforcement” 
nevertheless provide a firm foundation for reasonable- 
suspicion analysis, id. at 418. The Court noted that just 
as jurors are permitted to make determinations based 
on all the information before them, without rigid rules 
for weighing the evidence, “so are law enforcement 
officers.” Ibid.; see also Sokolow, 490 U.S. at 7-8. 

In Illinois v. Gates, 462 U.S. 213 (1983), the Court 
reached a similar conclusion in the context of probable- 
cause determinations. The Illinois Supreme Court had 
held that an informant’s tip could not contribute to 
probable cause unless the tip (1) revealed the infor- 
mant’s basis of knowledge, and (2) provided facts 
establishing either the veracity of the information or, 
alternatively, the reliability of the report. Id. at 228- 
229; see Spinelli v. United States, 393 U.S. 410, 413-416 
(1969). This Court rejected that rule and held that the 
“totality-of-the-circumstances approach is far more 
consistent with our prior treatment of probable cause 
than is any rigid demand that specific ‘tests’ be satisfied 
by every informant’s tip.” 462 U.S. at 230-231. “One 
simple rule,” the Court concluded, “will not cover every 

suggested that it is not helpful to disaggregate and assign different 
weights to various categories of factors. Id. at 1142 (“[W]e now 
have different classes of factors—regular and jumbo. How many 
regular factors add up to make a substantial factor? And how many 
substantial factors amount to reasonable suspicion? I have no clue, 
which makes me think that cops on their beats all over this circuit 
will have some trouble figuring it out as well.”). 

23 

situation.” Id. at 231-232 (internal quotation marks 
omitted). The two-pronged test applied by the state 
court “encouraged an excessively technical dissection of 
informants’ tips,” and focused “undue attention * * * 
on isolated issues that cannot sensibly be divorced from 
the other facts presented to the magistrate.” Id. at 234- 
235. The Court applied the reasoning of Gates to the 
reasonable-suspicion inquiry in Sokolow, 490 U.S. at 7- 

8. 

In Ornelas v. United States, 517 U.S. 690 (1996), the 
Court made a similar point in holding that district 
courts’ determinations about the existence of rea- 
sonable suspicion (and probable cause) are subject to de 
novo review. The Court acknowledged in Ornelas 
that the totality-of-the-circumstances rule “is multi- 
faceted,” 517 U.S. at 698, and that “[a]rticulating 
precisely what ‘reasonable suspicion’ * * * mean[s] is 
not possible,” id. at 695. But the Court observed that 
contextual application of a “fluid concept[]” better fits 
the Fourth Amendment’s reasonableness standard than 
any “neat set of legal rules.” Id. at 695-696 (internal 
quotation marks omitted). See also Ker v. California, 
374 U.S. 23, 33 (1963) (because “standards of rea- 
sonableness under the Fourth Amendment are not 
susceptible of Procrustean application,” “[e]ach case is 
to be decided on its own facts and circumstances”). 

This Court’s repeated rejection of inflexible rules for 
reasonable-suspicion analysis reflects the “the myriad 
factual situations that arise” in law enforcement. 
Cortez, 449 U.S. at 417. That variety makes it ex- 
tremely difficult to craft rules that are sufficiently 
general to be useful in a broad range of cases, yet 
sufficiently specific to be meaningful in practical appli- 
cation. It also would be unreasonable to expect law- 
enforcement officers to recall and apply, “on the spur 

24 

(and in the heat) of the moment” (Atwater v. City of 
Lago Vista, 121 S. Ct. 1536, 1553 (2001)), a large and 
ever-increasing body of judicial precedent regarding 
what factors may or may not be considered, and what 
amount of weight must be assigned to each cognizable 
factor. Cf. id. at 1553-1555 (noting practical difficulty of 
applying a rule that forbids warrantless arrests for a 
limited category of crimes). 

The particular rules adopted by the court of appeals 
in this case compound the practical problems inherent 
in any effort to limit the totality-of-the-circumstances 
approach. The Ninth Circuit would require law- 
enforcement officers to ignore facts that, based on the 
officer’s training and experience, contribute to 
reasonable suspicion. Whenever a fact observed by an 
officer already has been found irrelevant as a matter of 
law under the Ninth Circuit’s approach, the officer 
must attempt to exclude the fact from his or her 
assessment of the situation. The officer thus is left to 
guess about what degree of suspicion would exist in the 
absence of the forbidden fact. Officers also must 
attempt to anticipate whether other factors they deem 
significant under the totality of the circumstances 
might fail an ill-defined standard of “sufficient” 
relevance when isolated from the surrounding facts 
during judicial proceedings that may occur “months and 
years after [the stop] is made.” Atwater, 121 S. Ct. at 
1553-1554. The result of the court’s rule would be to 
substitute an appellate court’s “library analysis” for 
“common-sense conclusions * * * by those versed in 
the field of law enforcement.” Cortez, 449 U.S. at 418. 

3. The court of appeals further suggested (Pet. App. 
12a-17a) that some types of activity should be excluded 
from the reasonable-suspicion inquiry because: (1) they 
are almost always innocent; (2) they invite subjective 

25 

application by law-enforcement officers; or (3) consider- 
ing them would put some groups of law-abiding citizens 
(particularly members of minority groups) at a height- 
ened risk of being stopped by law-enforcement officers. 
The court of appeals’ concerns provide no basis for 
departing from the totality-of-the-circumstances test. 

a. With respect to the court of appeals’ view that 
certain behavior is virtually always innocent, this Court 
has settled beyond question that behavior can be 
common among law-abiding citizens, and innocent to 
untrained eyes, yet nevertheless relevant to reason- 
able-suspicion analysis. In Sokolow, for example, the 
Court explained that facts that individually are “quite 
consistent with innocent travel”—such as paying cash 
for an airline ticket or taking a long flight to Miami and 
staying only a short time—can “together * * * 
amount to reasonable suspicion.” 490 U.S. at 8-9. Like- 
wise, the Wardlow Court rejected the argument that 
fleeing from the police could not support reasonable 
suspicion because “there are innocent reasons” why one 
might run from law-enforcement officers. 528 U.S. at 
125. Noting that “[e]ven in Terry, the conduct justify- 
ing the stop was ambiguous and susceptible of an 
innocent explanation,” the Court reiterated that wholly 
lawful conduct can create ambiguity about possible 
illegal activity and thereby warrant an investigative 
stop. Id. at 125-126; see id. at 130 n.4 (Stevens, J., 
concurring in part and dissenting in part) (“sometimes 
behavior giving rise to reasonable suspicion is entirely 
innocent”); Terry, 392 U.S. at 22-23. See also Cortez, 
449 U.S. at 419 (“[W]hen used by trained law enforce- 
ment officers, objective facts, meaningless to the 
untrained, can be combined with permissible deductions 
from such facts to form a legitimate basis for suspicion 

26 

of a particular person and for action on that suspi- 
cion.”). 

11 

Thus, it was error for the court of appeals categori- 
cally to dismiss deceleration upon seeing a Border 
Patrol vehicle as “in no way indicative of criminal 
activity” (Pet. App. 12a). See, e.g., United States v. 
Villalobos, 161 F.3d 285, 291 (5th Cir. 1998) (“While we 
recognize that deceleration is a common and often 
completely innocent response to the approach of a 
patrol car, we hold that it may be one factor contri- 
buting to the reasonable suspicion justifying a stop.”). 

12 

11 Some “innocent” behavior enjoys specific constitutional pro- 
tection that may affect its consideration as part of the reasonable- 
suspicion inquiry. See Florida v. Bostick, 501 U.S. 429, 437 (1991) 
(“We have consistently held that a refusal to cooperate [with law- 
enforcement officers], without more, does not furnish the minimal 
level of objective justification needed for a detention or seizure.”); 
Terry, 392 U.S. at 34 (White, J., concurring) (“[A]nswers may not 
be compelled, and refusal to answer furnishes no basis for an 
arrest, although it may alert the officer to the need for continued 
observation.”); see also INS v. Delgado, 466 U.S. 210, 216-217 
(1984) (if an individual declines to consent to questioning by the 
police “and the police take additional steps * * * to obtain an 
answer, then the Fourth Amendment imposes some minimal level 
of objective justification to validate the detention or seizure”). No 
such protected behavior was an ingredient of the officer’s rea- 
sonable suspicion in this case. 

12 Sudden deceleration may indicate, on the particular facts, that 
the driver is attempting to avoid the police. See, e.g., Villalobos, 
161 F.3d at 287, 291 (car “decelerated and fell back a mile or more” 
after being passed by a Border Patrol vehicle); United States v. 
Magana, 797 F.2d 777, 781-782 (9th Cir. 1986) (driver slows from 
70 to 45 miles per hour, apparently to avoid passing INS vehicles). 
Sudden deceleration also may suggest under the circumstances 
that the driver is unusually distracted by or nervous upon seeing 
the police, which would contribute to suspicion of illegal activity. 
See, e.g., United States v. Guerrero-Barajas, 240 F.3d 428, 433 (5th 

27 

The court of appeals likewise erred when it ruled 
(Pet. App. 17a) that the apparent presence of cargo on 
the floor of respondent’s minivan was “too common to 
be of any relevance.” The court of appeals did not 
dispute that a vehicle’s “heavily loaded” appearance can 
suggest concealment of illegal aliens, Brignoni-Ponce, 
422 U.S. at 885, but it limited that principle to situa- 
tions in which “the vehicle [i]s riding low or respon- 
d[ing] sluggishly to bumps,” Pet. App. 16a-17a. The 
court’s limitation is plainly inappropriate, because other 
observations—even “common” ones—may raise reason- 
able questions about the presence of hidden illegal 
aliens in a vehicle. 

13 

For similar reasons, the court of appeals erred by 
barring consideration of Agent Stoddard’s belief that 
respondent’s minivan was not associated with a local 
ranch. See Pet. App. 14a-15a. Brignoni-Ponce estab- 

Cir. 2001) (“[T]he driver slowed and began to swerve within his 
lane once the [Border Patrol] Agents began to follow him.”); 
United States v. Lopez-Martinez, 25 F.3d 1481, 1485 (10th Cir. 
1994); United States v. Cardona, 955 F.2d 976, 981 (5th Cir. 1992) 
(vehicle slowed and began weaving after Border Patrol agents 
began following it, indicating that the driver was watching the 
agents in his rearview mirror). 

13 This Court, for example, has held that the use of bed sheets to 
cover the windows of a pickup truck’s camper shell supported an 
inference that the truck was carrying hidden cargo. United States 

v. Sharpe, 470 U.S. 675, 682 n.3 (1985). Similarly, the Fifth Circuit 
held that a tarp over the bed of a pickup truck, together with the 
presence of a spare tire in the back seat (suggesting that extra 
room was needed in the bed), supported reasonable suspicion of 
alien smuggling. United States v. Orozco, 191 F.3d 578, 582 (5th 
Cir. 1999). In United States v. Magana, the Ninth Circuit held 
that a cargo of plywood and clothing that obstructed the view into 
the back of a pickup truck was a factor that justified a stop to 
check for illegal aliens. 797 F.2d at 780-781. 

28 

lished that “the usual patterns of traffic on the par- 
ticular road” where a stop is made are potentially rele- 
vant to reasonable suspicion. 422 U.S. at 884-885. And 
the courts of appeals recognize that an unfamiliar 
vehicle can raise legitimate questions in the mind of an 
experienced law-enforcement officer. 

14 

b. The court of appeals also erred in suggesting (Pet. 
App. 12a, 13a-14a) that facts relating to an individual’s 
acknowledgment of, or failure to acknowledge, a law- 
enforcement officer should be excluded from Terry 
analysis because officers otherwise may apply them 
subjectively. The court reasoned that the range of 
behavior that may be deemed suspicious is so broad 
that “reliance upon ‘suspicious’ looks [or, as the case 
may be, the failure to look] can . . . easily devolve into 
a case of damned if you do, equally damned if you 
don’t.” Id. at 13a (quoting United States v. Montero- 
Camargo, 208 F.3d 1122, 1136 (9th Cir.) (en banc), cert. 
denied, 121 S. Ct. 211 (2000)) (court’s alterations). 

15 

14 See, e.g., United States v. Gonzalez, 190 F.3d 668, 670, 671-672 
(5th Cir. 1999) (agents’ failure to recognize vehicle supports 
reasonable suspicion); Magana, 797 F.2d at 780 (“[T]he out-of-state 
license plate indicated that the truck did not belong to any local 
farmer.”); United States v. Leyba, 627 F.2d 1059, 1064 (10th Cir.) 
(license plate from a neighboring State contributes to reasonable 
suspicion of alien trafficking where Border Patrol agent did not 
recognize the vehicle as local traffic), cert. denied, 449 U.S. 987 
(1980); United States v. Sarduy, 590 F.2d 1355, 1356, 1358 (5th Cir. 
1979) (where agents “knew ‘just about everybody that lives out on 
the ranches,’ ” their failure to recognize a pickup truck supported 
reasonable suspicion). 

15 In his dissenting opinion in Sokolow, Justice Marshall made a 
similar argument that criminal “profiles” have a “chameleon-like 
way of adapting to any particular set of observations.” 490 U.S. at 
13 (internal quotation marks omitted). Justice Marshall indicated, 
however, that he did not consider such concerns well-founded 

29 

As the Ninth Circuit correctly recognized in 
Montero-Camargo, however, facts such as “eye contact 
[with an officer], or the lack thereof * * * must be 
evaluated in light of the circumstances of each case.” 
208 F.3d at 1136 (internal quotation marks omitted). A 
driver’s quick glance at a law-enforcement vehicle in a 
rear-view mirror may be insignificant, ibid., whereas it 
would be relevant that a pedestrian looked at an officer 
just before he rushed to a car and drove away, United 
States v. Gordon, 231 F.3d 750, 755, 756 (11th Cir. 2000). 
Likewise, looking away from a law-enforcement officer 
may be “quite natural” when there is other, eye- 
catching activity to view, United States v. Pulido- 
Santoyo, 580 F.2d 352, 354 (9th Cir.), cert. denied, 439 
U.S. 915 (1978), but highly relevant when it appears to 
be an attempt to conceal one’s face. See, e.g., Sigmond- 
Ballesteros, 247 F.3d at 949; United States v. Tate, 648 
F.2d 939, 941, 942 (4th Cir. 1981); see also Brignoni- 
Ponce, 422 U.S. at 885 (Border Patrol may take into 
account an observation that “persons [are] trying to 
hide.”). The significance of looking at or acknowledging 
an officer therefore must be decided in context. 

c. Finally, the court of appeals suggested (Pet. App. 
15a) that it is appropriate to exclude factors such as 
where a person lives because considering such factors 
in reasonable-suspicion analysis may affect particular 
socioeconomic groups or minorities disproportionately. 
The court of appeals did not suggest that Agent 
Stoddard harbored any impermissible motive when he 
stopped respondent’s minivan, and the officer’s subjec- 

when an investigative stop is supported by “case-by-case police 
work” and “fact-specific inferences,” rather than “mechanistic 
application of a formula of personal and behavioral traits in 
deciding whom to detain.” Ibid. 

30 

tive intent would be irrelevant in Fourth Amendment 
analysis. “[T]he Constitution prohibits selective 
enforcement of the law based on considerations such as 
race,” but “the constitutional basis for objecting to 
intentionally discriminatory application of laws is [equal 
protection], not the Fourth Amendment.” Whren v. 
United States, 517 U.S. 806, 813 (1996). 

16 

In the absence of any impermissible motive for the 
stop in this case, the court of appeals appeared to 
conclude (Pet. App. 15a) that the objective fact that an 
individual resides in an area known for crime must be 

16 As a matter of Fourth Amendment law, the courts of appeals 
generally hold that race and ethnicity are insufficient in them- 
selves to support an investigative stop, but may contribute in some 
circumstance to a well-founded suspicion of criminal conduct. See, 

e.g., United States v. Morrison, 2001 WL 687624, at *4 (7th Cir. 
June 20, 2001) (“When police are searching for a bank robber de- 
scribed as a black male, it is reasonable for them to be looking for a 
black man.”); United States v. Lopez-Martinez, 25 F.3d 1481, 1487 
(10th Cir. 1994) (Hispanic appearance relevant to Border Patrol 
stop); United States v. Garcia, 23 F.3d 1331, 1335 (8th Cir. 1994) 
(“nationality or race may be relevant factors in some instances”); 
but see Montero-Camargo, 208 F.3d at 1131-1135 (agreeing that 
racial or ethnic appearance “may be considered when the sus- 
pected perpetrator of a specific offense has been identified as 
having such an appearance,” id. at 1134 n.22, but holding that His- 
panic appearance generally may not be considered in areas with 
large Hispanic populations). See also Brignoni-Ponce, 422 U.S. at 
886-887 (“The likelihood that any given person of Mexican ancestry 
is an alien is high enough to make Mexican appearance a relevant 
factor, but standing alone it does not justify stopping all Mexican- 
Americans to ask if they are aliens.”); United States v. Montoya de 
Hernandez, 473 U.S. 531, 538 (1985) (“Automotive travelers may 
be stopped at fixed checkpoints near the border without individu- 
alized suspicion even if the stop is based largely on ethnicity.”) 
(citing United States v. Martinez-Fuerte, 428 U.S. 543, 562-563 
(1976)). 

31 

disregarded as matter of law. Yet the facts of this case 
illustrate that the court of appeals’ prohibition on 
considering the address to which a vehicle is registered 
(which the court treated as a proxy for the residency of 
the vehicle’s occupants) is unfounded. The 400 block of 
4th Street in Douglas was known for having “stash 
houses” and as a base for smuggling aliens and narcot- 
ics away from the border area. J.A. 37-38, 66-67. The 
van’s registration to that block therefore suggested 
that respondent’s northbound trip may have originated 
in a smuggling area, which supported an inference that 
the van was using the back roads for smuggling. The 
registration might have had very different implications 
if, for example, the van had been parked in a shopping 
district near the 400 block of 4th Street. That is 
another illustration of the fundamental point, missed by 
the court of appeals in this case, that reasonable-suspi- 
cion analysis must be undertaken “in light of the par- 
ticular circumstances.” Terry, 392 U.S. at 21; see id. at 
15 (“No judicial opinion can comprehend the protean 
variety of the street encounter, and we can only judge 
the facts of the case before us.”). 

II. THE INVESTIGATIVE STOP IN THIS CASE WAS 
LAWFUL 

Because of its methodological errors, the court of 
appeals reached the wrong result in this case. The 
court of appeals never purported to consider “the whole 
picture” seen by Agent Stoddard. Cortez, 449 U.S. at 
417. Instead, the court disaggregated the factors that 
Agent Stoddard deemed collectively significant, and 
dismissed them one by one. The court of appeals thus 
transformed the reasonable-suspicion inquiry into a 
series of hurdles, each of which the prosecution had to 

32 

overcome by showing the significance of an isolated 
fact. 

Had the court of appeals applied the reasonable- 
suspicion test correctly, it would not have asked 
whether each factor individually suggested illegal 
activity. It would have asked whether the totality of 
the circumstances known to Agent Stoddard and recog- 
nized by the district court justified a brief stop of 
respondent’s vehicle to investigate the possibility of a 
crime. The answer to that question is “Yes.” 

As the district court explained (Pet. App. 22a-25a), 
Agent Stoddard knew at the time he stopped respon- 
dent that respondent was taking a lightly traveled 
route that smugglers used to evade a fixed border 
patrol checkpoint. The route chosen by respondent 
required a 40-mile trip over mostly dirt roads, when 
taking the highway would have been quicker and 
easier. Respondent was traveling at a time of day when 
smuggling activity in the area increased because of the 
Border Patrol’s shift change. 

17 He was driving a type of 
vehicle that was capable of holding concealed illegal 
aliens or bulky drugs and had been used by smugglers 
in the recent past. Agent Stoddard did not recognize 
the vehicle as being associated with any of the ranches 

17 The court of appeals held that the time at which respondent 
triggered the Border Patrol’s sensors had “little probative value” 
because the first sensor was triggered approximately 45 minutes 
before the scheduled 3 p.m. shift change. Pet. App. 18a. The court 
of appeals’ reasoning ignored the time it takes agents to drive back 
to the checkpoint for the shift change. Consistent with Agent 
Stoddard’s testimony (J.A. 47), the district court found that the 
sensor was triggered at approximately the same time that “agents 
are returning to the checkpoint[,] leaving this area open” to 
smugglers. Pet. App. 23a. 

33 

18 Respondent’s hesitation at the corner of 
Rucker Canyon Road and Kuykendall Cutoff Road 
further suggested that he was not familiar with the 
area (or, alternatively, that respondent was unusually 
distracted by the Border Patrol vehicle behind him). 
See Pet. App. 22a-24a; J.A. 36. 

Agent Stoddard also knew that the minivan was 
registered to a particular block in Douglas that was 
very close to the Mexican border and was commonly 
used as a staging area for smuggling illegal aliens and 
narcotics further north. Pet. App. 25a; J.A. 37-38, 66- 

67. That information, together with the minivan’s 
northbound route from Douglas, supported an inference 
that the vehicle had started its unusual trip at “an 
often-used smuggling area” (Pet. App. 25a). See p. 31, 
supra. 

in the area. 

19 

18 When disregarding Agent Stoddard’s failure to recognize the 
minivan, the court of appeals assumed (Pet. App. 14a-15a, 17a-18a) 
that campers, hikers, bikers, picnickers, and tourists commonly 
take the same route as respondent. Yet the district court found (id. 
at 22a) that respondent was neither heading toward any nearby 
recreation area when he was stopped, nor taking a customary 
route to recreation areas located farther north. Those factual 
findings were binding on the court of appeals unless clearly 
erroneous, Ornelas, 517 U.S. at 699, and respondent did not 
challenge them in his appellate brief. 

19 The court of appeals stated that “Agent Stoddard did not 
explain the factual basis for” his belief that smuggling activity 
occurred in the area to which the minivan was registered. Pet. 
App. 16a. In fact, Agent Stoddard testified at the suppression 
hearing that he was aware that officers apprehended “several 
groups [of illegal aliens] * * * daily in that area attempting to get 
into stash houses and such.” J.A. 67. 

34 

Respondent had slowed down sharply upon seeing 
Agent Stoddard’s Border Patrol vehicle. 

20 Respondent 
and his adult passenger both appeared nervous when 
they passed Agent Stoddard’s truck, and the children 
engaged in four or five minutes of odd waving that 
seemed to be directed by the adults. Pet. App. 23a-25a; 
J.A. 35, 61. 

21 

20 The posted speed limit on Rucker Canyon Road, at the 
intersection of Leslie Canyon Road, is 35 miles per hour. J.A. 83, 
171. Later on respondent’s route, the speed limit drops to 25 miles 
per hour. J.A. 179. Respondent, however, made no argument 
below that he slowed in order to avoid exceeding the speed limit 
when he passed Agent Stoddard’s vehicle. Cf. United States v. 
Diaz, 977 F.2d 163, 165 (5th Cir. 1992) (“[T]here is nothing 
suspicious about a speeding car slowing down after a marked 
patrol unit turns to follow.”) (emphasis added). To the contrary, 
respondent’s counsel consistently asserted that respondent never 
violated any traffic laws. J.A. 134; see also Resp. C.A. Br. 30 
(arguing that respondent was engaged in “non-dangerous driving, 
which violate[d] no traffic laws” and noting that Agent Stoddard 
did not stop respondent for a traffic violation). 

21 The court of appeals mischaracterized the record when it 
suggested (Pet. App. 13a-14a) that Agent Stoddard relied on the 
mere facts that respondent failed to acknowledge him when driv- 
ing past, and that the children waved. Agent Stoddard concluded 
from respondent’s posture and behavior that he was nervous. Id. 
at 24a; J.A. 33, 59-60. That was indisputably relevant. See 
Wardlow, 528 U.S. at 124; Sokolow, 490 U.S. at 4, 6, 8, 9 n.4; see 
also Pet. 18 n.7 (citing court of appeals decisions). Likewise, the 
children’s waving was relevant because (as the district court found 
after seeing Agent Stoddard imitate the children, see J.A. 35) it 
was done in a “methodical,” “mechanical,” and “abnormal way 

* * * without even turning around to look at the agent.” Pet. 
App. 25a. The unusual manner of the waving led Agent Stoddard 
to suspect that the adults in the van were coaching the children. 
And the apparent coaching—not simply the waving—contributed 
to Agent Stoddard’s suspicion. J.A. 35, 61, 73. See generally 
Ornelas, 517 U.S. at 699 (reviewing court should “give due weight 

35 

There appeared to be cargo on the floor of the van, 
where it could not be seen. Pet. App. 24a-25a. Yet 
respondent, whom Agent Stoddard did not recognize as 
a local driver, had already passed the turn-offs for local 
campsites and recreation areas, id. at 22a, and a driver 
making a long-distance trip for which luggage would be 
needed would be expected to use the highway to avoid 
a “40-mile trip at least, through a dirt road,” ibid. As 
the district court aptly explained, the cargo on the floor 
of the minivan “[c]ould have been camping equipment, I 
suppose, had not all the other facts been there pointing 
to the possibility of illegal activity.” Id. at 25a. 

Agent Stoddard appropriately “piec[ed] together the 
information at [his] disposal,” Cortez, 449 U.S. at 419, 
including the absence of any facts negating his infer- 
ences about possible illegal activity. He correctly 
concluded, based on specific, articulable facts and rea- 
sonable deductions that reflected his training and 
experience, “that criminal activity ‘may be afoot.’ ” 
Sokolow, 490 U.S. at 7 (quoting Terry, 392 U.S. at 30); 
see Cortez, 449 U.S. at 418. As the district court deter- 
mined (Pet. App. 21a-25a), Agent Stoddard’s decision to 
investigate further by stopping and questioning respon- 
dent was consistent with the Fourth Amendment. 

to inferences drawn from th[e] facts by resident judges and local 
law enforcement officers.”). 

36 

CONCLUSION 

The judgment of the court of appeals should be 
reversed. 

Respectfully submitted. 

THEODORE B. OLSON 
Solicitor General 

MICHAEL CHERTOFF 

Assistant Attorney General 

MICHAEL R. DREEBEN 

Deputy Solicitor General 

AUSTIN C. SCHLICK 

Assistant to the Solicitor 

General 

DEBORAH WATSON 

Attorney 

JULY 2001