The Journal of The DuPage County Bar Association

Back Issues > Vol. 14 (2001-02)

NIU's Northern Exposure
Airport Exceptions to the Fourth Amendment’s Warrant Requirement
By Brett A. Skean

In light of the terrorist attacks of September 11th, the civil liberties enjoyed by airline passengers are likely to be somewhat curtailed in favor of more stringent security measures. New procedures could involve an increase in the regularity of “warrantless” searches by airport security personnel, resulting in a more substantial intrusion into the privacy of those seeking to fly the friendly skies. Traditionally, to be considered reasonable under the Fourth Amendment, most searches had to be executed pursuant to a warrant. However, courts have justified airport security searches conducted without a warrant or probable cause if they are: (1) searches that do no more than “stop and frisk”; (2) searches in furtherance of an administrative purpose; (3) searches conducted at a border or other critical zone; and (4) searches conducted with the consent of the person searched.1

This article summarizes the doctrines that have been used by courts in determining the constitutionality of airport searches.

Stop and Frisk Searches
Warrantless “stop and frisk” searches conducted by law enforcement officials were first addressed in the Supreme Court’s 1968 decision in Terry v. Ohio.2 Prior to that case, the Court had “never before been squarely presented” with the “difficult and troublesome issues regarding [this] sensitive area of police activity.”3 The Court initially noted that “wherever an individual may harbor a ‘reasonable expectation of privacy,’ he is entitled to be free from governmental intrusion,” noting the previous standard of reasonableness set forth in Katz v. United States.4 However, “what the Constitution forbids is not all searches and seizures, but unreasonable searches and seizures.”5 In Terry, a plain-clothes police officer observed the defendant Terry and two other individuals engage in suspicious behavior that led the officer to believe the individuals were planning a daylight robbery.6 The police officer approached the individuals, identified himself as a police officer, and asked for the individuals’ names.7 A mumbled response to his inquiries prompted the police officer to grab Terry and pat down the outside of his clothing seeking to reveal the presence of any weapons.8

According to the trial court, such a search was permitted in order to guarantee the safety of the investigative officer for, without such a search, the answer from a suspected criminal to an inquiry by the officer might be a bullet from a concealed weapon.9 In affirming, the Supreme Court held that a police officer could “seize” an individual, i.e., stop and temporarily hold the person, if the officer reasonably and objectively believes that “criminal activity may be afoot.”10 Once he has detained the suspect, the officer is permitted to conduct a “carefully limited search of the outer clothing of [the individual] in an attempt to discover weapons which might be used to assault him,”11 if the officer reasonably believes that the suspect is armed and dangerous. The Court noted that such a search was limited in nature, a search for weapons, and was “not a general exploratory search for… evidence of criminal activity.”12 Thus, in Terry, the Supreme Court established the doctrine that allowed a limited frisk for weapons without the requirement of a search warrant.

United States v. Lopez13 was one of the first decisions regarding the constitutionality of airport security procedures. Lopez met the FAA’s criteria for its administrative hijacker profile, and, while proceeding through the security checkpoint, activated a metal detector.14 As a result, two Deputy United States Marshals frisked Lopez for weapons, and found a tinfoil covered plastic envelope filled with heroin.15 The district court found that “the only exception to the warrant rule under which the search of this defendant [could] be justified is the protective ‘frisk’ for weapons authorized by Terry v. Ohio.”16 The Lopez court did not specifically address whether the defendant’s expectation of privacy had been violated, but noted the “courts are in a position to prevent abuse” when it arises.17

Lopez’s limited holding was soon expanded to justify more intrusive searches under the Terry “stop and frisk” doctrine. In United States v. Epperson,18 the Fourth Circuit allowed a search of an airline passenger to be carried out solely on the basis of the activation of a magnetometer, without any regard to whether the passenger met the criteria of the hijacker profile.19 In so holding, the court noted that “ordinarily the securing of a warrant is supported by an affidavit of facts and circumstances sufficient to enable an impartial magistrate to judge its necessity and justification, but air piracy and its threat to national air commerce is known to all and may be judicially noticed.”20 The court reasoned that requiring the prerequisite warrant, which the judicial officer would grant anyway, would “exalt form over substance.”21 As the court stated, “[T]he danger is so overwhelming, and the invasion of privacy so minimal, that the warrant requirement is excused by exigent national circumstances.”22 The court also found that the scope of the search was reasonably related to its purpose, and “fully justified the minimal invasion of personal privacy by [the] magnetometer… the person scrutinized is not even aware of the examination.”23 It was clear to the court “that to innocent passengers the use of a magnetometer to detect metal on those boarding an aircraft is not a resented intrusion on privacy, but, instead, a welcome reassurance of safety.”24 Such a search was more than reasonable; it was a “compelling necessity to protect essential air commerce and the lives of passengers.”25

The Second Circuit extended the stop and frisk approach in United States v. Bell,26 holding that the search need not be limited to weapons which might be used against the officer personally.27 Not only did Bell meet the hijacker profile and activate a magnetometer, he had no identification and admitted to the security official that he was out on bail for attempted murder and narcotics charges.28 In upholding the search, the court noted there is an “apprehension of the officer for the safety of others as well as himself.”29 “[T]he weapon of the skyjacker is not limited to the conventional weaponry of the bank robber or of the burglar… [h]is arsenal may well include explosives.”30 Two years later, in United States v. Clark,31 the Second Circuit extended its holding in Bell and applied the stop and frisk analysis to justify searches of carry-on luggage. As in Bell, the defendant met the criteria of the hijacker profile, activated the magnetometer, had no identification and acted “strangely.”32 While these subsequent decisions extended the stop and frisk doctrine past the dimensions enunciated by Terry itself, it is clear that courts are following the admonition of the Epperson court that “reasonableness is still the ultimate standard,”33 and that reasonableness was to be determined by balancing the governmental interests with the individual’s right to privacy.34

Administrative Searches
The United States Supreme Court addressed administrative searches in Camara v. Municipal Court of City and County of San Francisco.35 Camara, the lessee of a ground floor of apartment building, was charged with violating the city housing code for refusing to permit warrantless inspection of his premises by municipal health and safety inspectors.36 In upholding the administrative and regulatory search, the Court held that the “primary governmental interest at stake is to prevent even the unintentional development of conditions which are hazardous to public health and safety.”37 According to the Camara Court:

[T]he only effective way to seek universal compliance with the minimum standards required by municipal codes is through routine periodic inspections of all structures. It is here that the probable cause debate is focused, for the agency’s decision to conduct an area inspection is unavoidably based on its appraisal of conditions in the area as a whole, not on its knowledge of conditions in each particular building.38

The Camara doctrine was extended to airport searches in United States v. Davis,39 where a routine security check revealed that the defendant was attempting to board an airplane with a loaded gun.40 The Ninth Circuit refused to limit the justification for airport security searches to the Terry stop and frisk doctrine. Instead, the court held that searches conducted in furtherance of a regulatory administrative purpose might be permissible under the Fourth Amendment, despite the lack of either a warrant or probable cause.41 Administrative searches stem from the government’s need to oversee a highly regulated activity.42 When deciding whether a search is administrative in nature, the court must make a dual determination: (1) whether the search serves a narrow but compelling administrative objective and (2) whether the intrusion is as “limited as is consistent with satisfaction of the administrative need that justifies it.”43 The Davis court balanced the competing interests of the government’s prevention of airline hijacking and the passenger’s expectation of privacy and, like the Epperson court, found that the scales tipped in favor of the government. “The need to prevent airline hijacking is unquestionably grave and urgent. The potential damage to person and property from such acts is enormous.”44 Because the security measures were not utilized to secure evidence in a criminal investigation, but were rather used as a regulatory means to thwart the threat of airplane hijackings, the Davis court characterized the search as administrative.45 “The essential purpose of the scheme is not to detect weapons or explosives or to apprehend those who carry them, but to deter persons carrying such material from seeking to board at all.”46 If, however, such a regulatory search becomes “subverted into a general search for evidence of crime… the courts will exclude the evidence obtained.”47 Once the administrative search is determined to be an exception to the warrant requirement, the constitutionality of the search will be upheld if it meets the Fourth Amendment’s standard of reasonableness.48 The Davis court concluded that a “pre-boarding screening of all passengers and carry-on articles sufficient in scope to detect the presence of weapons or explosives is reasonably necessary “ to meet the need of preventing airline hijacking.49 A warrant is not required and would only “frustrate the governmental purpose behind the search.”50 The court did stress one important caveat to the administrative search: to meet the test of reasonableness, “airport screening searches are valid only if they recognize the right of a person to avoid the search by electing not to board the aircraft.”51 Because the administrative purpose recognized in Davis was to deter passengers from carrying weapons or explosives onto an airplane, the search cannot be justifiably applied to those passengers who did not board the airplane. Such a search would be outside the scope of the administrative purpose and be unreasonable. Therefore, the option of not flying was crucial to the Davis court. “We have held that, as a matter of constitutional law, a prospective passenger has a choice: he may submit to a search of his person and immediate possessions as a condition to being boarding; or he may turn around and leave.”52

Borders and Other Critical Zones
The border exception to the Fourth Amendment’s warrant requirement has long been established in American jurisprudence. Since the founding of the United States, Congress “has granted the Executive [branch] plenary authority to conduct routine searches and seizures at the border, without probable cause or a warrant, in order to regulate the collection of duties and to prevent the introduction of contraband into this country.”53 This extension of police power is derived from the inherent authority of the national sovereign to defend itself from outside threats and harmful influences, including the “power to prohibit the export of its currency, national treasures, and other assets,”54 and extends to all routine searches at the nation’s borders, irrespective of whether persons or effects are entering or exiting from the country.55 Consistent with Congress’ sovereign power to protect the nation by stopping and examining individuals who wish to enter the country, the Fourth Amendment’s standard of reasonableness is “qualitatively different at the international border than in the interior.”56 Therefore, searches occurring at an international border are justified simply because they occur at the border. Entrants have no reasonable expectation of privacy and routine searches of their persons and belongings are “not subject to any requirement of reasonable suspicion, probable cause or warrant.”57 To fall under the exception, the searches must be routine, and in making that determination, the courts have looked to the degree of intrusion into the entrant’s legitimate expectations of privacy.58 “Routine border inspections are those that do not pose a serious invasion of privacy and that do not embarrass or offend the average traveler.”59 The border search exception is further extended to those areas which are considered the functional equivalent” of an international border.60 A non-stop international flight arriving in Chicago or Saint Louis will be considered an entry at the border even though the flight has landed well within the boundaries of the United States. As a result, routine searches conducted upon the arrival of an international flight are considered an exception to the Fourth Amendment’s warrant requirement and are justified on reasonable suspicion alone.

The “critical zone” approach is an expansion of the border search doctrine. It theorizes that airports, by virtue of their special character are analogous to national borders and thus should be evaluated under a more lenient standard of reasonableness for Fourth Amendment considerations. United States v. Moreno61 was one of the first decisions to apply the “critical zone” approach, upholding the search of the defendant in an airport restroom. In holding that the airport was a “critical zone” akin to an international border, the Fifth Circuit observed that the airport was the “one channel through which all hijackers must pass before being in a position to commit their crime,” and was also the “one point where airport security officials can marshal their resources to thwart such acts before the lives of an airplane’s passengers and crew are endangered.”62 However, the court cautioned that it did not “propose to substitute the ‘suspicion standard’ applicable in border search cases for the Terry v. Ohio standard,” which was the basis for its decision.63 In United States v. Skipwith,64 the Fifth Circuit qualified its Moreno decision. The court again recognized airports as “critical zones” characteristic of international borders, but held that a different standard applies to searches conducted in the general airport area and those conducted at the boarding gate.65 Skipwith presented himself for boarding and aroused suspicion when he stated he had no identification.66 Further questioning revealed that he had purchased the ticket under an alias. A subsequent search revealed that Skipwith was attempting to smuggle a packet of heroin aboard.67 The court held that a search conducted at a boarding gate could be executed under the same standard as that of a search conducted at a border: mere suspicion alone was sufficient.68 The search itself was limited to those people attempting to board, mere passerby would not be subjected to the search. Thus, the “net” of security could “sweep no wider than necessary since the broad right to search is limited to the last possible point in time and space which could protect the aircraft, the boarding gate (or secure corridor entrance).”69 The person to be searched has to voluntarily come to and enter the search area, ensuring an opportunity to avoid the procedure by not entering the boarding area.70 Skipwith, then, appeared to limit the airport’s “critical zone” to the boarding gate, rather than the entire airport premises.

The Consent Exception
The final applicable exception to the Fourth Amendment’s warrant requirement involves searches conducted with the consent of the person being searched. Fourth Amendment rights can be waived by consent so long as the consent is freely and voluntarily given and not the result of fraud duress or coercion.71 The determination of consent must be made from a totality of the circumstances.72 The Davis court, while addressing administrative searches, recognized that consent is also a factor in determining whether the passenger’s right to privacy has been violated. The court recognized that in the airport screening area, the passenger has a choice of submitting to the search or leaving; individuals who choose to proceed, relinquish their Fourth Amendment rights.73 The Fifth Circuit has also acknowledged the importance of the passenger’s consent to be searched. Justifying the “critical zone” approach in Skipwith, the court grounded its opinion on the fact that “the person to be searched must voluntarily come to and enter the search area [and] has every opportunity to avoid the procedure by not entering the boarding area.”74 That distinction mitigates some of the offensiveness the screening process might incur.75

The Ninth Circuit addressed the consent exception more directly in United States v. Miner.76 Relying on Davis, the court held that Miner’s approaching the counter with the obvious intention of boarding the airplane constituted an implied “consent” within the meaning of Davis.77 In so holding, the court appeared to be particularly influenced with two key facts. First, the search occurred when “concern over the problem of airplane hijackings was at its peak”78 and “three months after the FAA had ordered the airlines to screen all potential passengers.”79 Second, Miner admitted that he had flown several times before and had seen “signs warning all passengers and their baggage were subject to search,”80 and knew what the warnings meant. Despite the prior notification, Miner still attempted to board the airplane. There was some conflicting evidence concerning Miner’s attempt to withdraw his “consent” and the Ninth Circuit remanded for clarification on those issues.81 However, the court noted that requesting to search Miner’s baggage “could be justified only if he continued to manifest an intention to board the plane, or if he otherwise consented to the search.”82 “At that point, the airline employees would have been justified in refusing to permit him to fly, but they could not compel him to submit to further search.”83 The Miner decision is best understood as holding that a defendant who approaches an airport check-in counter with the intention of boarding the plane impliedly consents to a search by airport security personnel. If the passenger then withdraws that consent by refusing to be subject to the search and refusing to board the plane, the search must be terminated.

The government has a substantial interest in protecting its air travelers and the recent terrorist attacks have shown that existing security measures are not adequate. Future judicial review will have to take the above exceptions into consideration when evaluating whether an individual’s Fourth Amendment rights have been violated as the result of an airport search.

1 See, e.g., United States v. Epperson, 454 F.2d 769 (4th Cir. 1972), cert. denied, 406 U.S. 947 (1972) (discussing stop and frisk searches applied to airport security); United States v. Davis, 482 F.2d 893 (9th Cir. 1973) (discussing administrative inspection doctrine); United States v. Skipwith, 482 F.2d 1272 (5th Cir. 1973) (discussing critical zone doctrine as a rationale for airport security searches); United States v. Miner, 484 F.2d 1075 (9th Cir. 1973) (discussing consent exception).
2 Terry v. Ohio, 392 U.S. 1 (1968).
3 Id. at 9-10.
4 Id. at 9 (quoting Katz v. United States, 389 U.S. 347, 381 (1967) (Harlan, J., concurring)).
5 Elkins v. United States, 364 U.S. 206, 222 (1960).
6 Terry, 392 U.S. at 6.
7 Id. at 6-7.
8 Id.
9 Id. at 8.
10 Id. at 30.
11 Id.
12 Id.
13 United States v. Lopez, 328 F. Supp. 1077 (E.D.N.Y. 1971).
14 Id. at 1081-1082.
15 Id.
16 Id. at 1093.
17 Id. at 1101.
18 454 F.2d 769 (4th Cir. 1972), cert. denied, 406 U.S. 947 (1972).
19 Id. at 770.
20 Id. at 771.
21 Id.
22 Id.
23 Id. at 771.
24 Id. at 772.
25 Id.
26 United States v. Bell, 464 F.2d 667 (2nd Cir. 1972), cert. denied, 409 U.S. 991 (1972).
27 Id. at 673.
28 Id. at 668-669
29 Id.
30 Id. at 674.
31 United States v. Clark, 498 F.2d 535 (2nd Cir. 1974) (holding that the standard set forth in Bell justified the search of the defendant’s person and effects).
32 Id. at 536.
33 Epperson, 454 F.2d at 771 (quoting Camara v. Municipal Court, 387 U.S. 523, 539(1967)).
34 Id.
35 Camara v. Municipal Court, 387 U.S. 523 (1966).
36 Id. at 525-527.
37 Id. at 535
38 Id. at 535-536.
39 United States v. Davis, 482 F.2d 893 (9th Cir. 1973).
40 Id. at 896.
41 Id. at 907-908.
42 Jonathan Lewis Miller, Search and Seizure of Air Passengers and Pilots: The Fourth Amendment Takes Flight, 22 Transp. L.J. 199, 206 (1994).
43 United States v. $124,570 United States Currency, 873 F.3d 1240, 1244-1245 (9th Cir. 1989) (quoting Davis, 482 F.2d at 910).
44 Davis, 482 U.S. at 910.
45 Id. at 908.
46 Id.
47 Id. at 909.
48 Id. at 910.
49 Id.
50 Id. (quoting Camara, 387 U.S. at 532).
51 Id. at 910-911.
52 Id. at 913.
53 United States v. Montoya de Hernandez, 473 U.S. 531, 537 (1985).
54 United States v. Oriakhi, 57 F.3d 1290, 1297 (4th Cir. 1995).
55 Id.
56 Montoya de Hernandez, 473 U.S. at 538.
57 Id.
58 United States v. Johnson, 991 F.2d 1287, 1291 (7th Cir. 1993).
59 Id.
60 Id. at 1290.
61 United States v. Moreno, 475 F.2d 44 (5th Cir. 1973), cert. denied, 414 U.S. 840 (1973).
62 Id. at 51.
63 Id. at 51 n.8.
64 United States v. Skipwith, 482 F.2d 1272 (5th Cir. 1973).
65 Id. at 1276-1277.
66 Id. at 1273-1274.
67 Id.
68 Id. at 1275.
69 Id. at 1276-1277.
70 Id. at 1275-1276.
71 Schneckloth v. Bustamonte, 412 U.S. 218, 248-249 (1973).
72 Id.
73 Davis, 482 F.2d at 913.
74 Skipwith, 482 F.2d at 1275-1276.
75 Id.
76 United States v. Miner, 484 F.2d 1075 (9th Cir. 1973).
77 Id. at 1076.
78 Id.
79 Id.
80 Id.
81 Miner, 484 F.2d at 1076.
82 Id.
83 Id.

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