Technology and the Fourth Amendment: Striking a Balance between Efficient Law Enforcement and the Right to Privacy by Gabriel de Corral

I. Introduction

The Fourth Amendment to the United States Constitution establishes, “The right of the people to be secure in their persons, houses, papers, and effects, against unreasonable searches and seizures, shall not be violated. …”[i]

The development of Fourth Amendment jurisprudence has continuously dealt with emerging technology and how it should be used to determine whether the use of certain technologies are a violation of a person’s constitutional rights.  Although the “exploitation of technological advances”[ii] by the government and law enforcement officials raises “grave constitutional questions under the Fourth Amendment,”[iii] it is important that these fantastic advances in the field of communication are not wasted merely because of a potential for their misuse.

The U.S. Supreme Court has yet to establish a test or rule that effectively outlines how emerging technology should be treated in light of the Fourth Amendment.[iv]  The Supreme Court has not yet decided whether the use of Global Positioning Systems (GPS) by police in criminal investigations constitutes a search under the Fourth Amendment, and moreover, has avoided the possible question of the constitutionality of any type of government “mass surveillance”[v] program.

This blog entry will argue that the use of a GPS device has become a “sufficiently routine part of modern life”[vi] and consequently, its use in criminal investigations should not implicate the Fourth Amendment.  Furthermore the added privacy protection of requiring a warrant for the use of a GPS device “would not justify the harm worked on law enforcement.”[vii]  Obtaining a warrant is a cumbersome process, and although meant to protect the interests of the public at large, it exacts a cost on law enforcement officials that require the ability to be expedient in their pursuits of possible criminal suspects.

Part II: What is “knowingly exposed to the public” will not be protected by the Fourth Amendment

The Fourth Amendment protects people against unreasonable searches and seizures.  A person will have standing to challenge an unreasonable search and seizure if he can show a legitimate expectation of privacy in the area searched.[viii]  Determining a legitimate expectation of privacy involves two requirements: first that the individual have an actual subjective expectation of privacy; and second, that the expectation of privacy be one that society accepts as reasonable.[ix]

Generally, reasonability will depend on societal expectations and social norms.[x] Thus, what might have been unreasonable in 1920 might not be so today.[xi]  Courts must look to “understandings that are recognized and permitted by society.”  The widespread use of GPS technology today suggests that it should not implicate Fourth Amendment protections when used by law enforcement officials to determine the location of a vehicle on public streets.[xii]

Justice O’Connor in Riley explains that privacy expectation depends on whether intrusion is a “sufficiently routine part of modern life.”[xiii]  In that case she reasoned that public air travel at 1,000 feet is a “sufficiently routine part of modern life that it is unreasonable for persons on the ground to expect that their curtilage will not be observed from the air at that altitude.”[xiv] Following this line of reasoning, in today’s world it is no longer reasonable to expect that anything anyone might expose to the public will remain private. It is settled law that there is no legitimate expectation of privacy over something that is “knowingly exposed to the public.”[xv]  When one travels on public streets all movements are within observation of someone else, the fact that it would be much more difficult to maintain surveillance over someone without the aid of technology should not matter.

The Supreme Court’s decision in United States v. Knotts established the applicable standard for electronically enhanced surveillance.[xvi]  Similar to what was stated in Katz, what is knowingly exposed to the public will not come under Fourth Amendment protection. Most Circuit Courts have followed this line of reasoning.[xvii]

Recently, however, some Circuit Courts have attempted to distinguish beeper tracking from GPS tracking because “the volume of information obtained is greater” with a GPS device than with the beeper tracker used in Knotts.[xviii]  This “aggregation approach,”[xix] should be rejected not only because it would be almost impossible to apply in practice but also because it would, in theory, “prohibit not only GPS-augmented surveillance, but any other police surveillance of sufficient length to support consolidation of data” into a discernible pattern or mosaic of information.[xx]  This unworkable rule would impose on law enforcement officials the impossible burden of attempting to discern when surveillance would become so “prolonged as to have crossed the threshold and created this allegedly intrusive mosaic.”[xxi]

Part III: The “aggregation approach” proposed by the D.C. Circuit is not the solution

The D.C. Circuit recently held that prolonged surveillance using a GPS device was an unreasonable search under the Fourth Amendment.[xxii]  The court distinguished the instant case by explaining that, unlike in Knotts, “the totality of the defendant’s movements over the course of a month – were not exposed to the public.”[xxiii]  It follows from Katz that “what a person knowingly exposes to the public  … is not subject of Fourth Amendment protection.”[xxiv]

In Knotts it was only a single journey in question, which could easily be exposed to anyone choosing to follow the vehicle and thus not subject to constitutional protection.[xxv]  However, over the course of a month it is almost impossible that anyone will observe all the movements undertaken during that span.[xxvi]  This case rested on the conclusion that although a person might be willing to convey his movements to the public on a single journey, he does not do so over the course of a month.  Being seen at a bar one time could mean something very different from being seen at a bar for thirty consecutive days.  In the former the person might be celebrating or meeting some friends after work, in the latter the person might be an alcoholic.

The current debate today looks at the “aggregation approach” proposed by the D.C. Circuit in Maynard.[xxvii]  Looking beyond the fact that this approach would “fail to provide a workable accommodation between the needs of law enforcement and the interests protected by the Fourth Amendment,” it goes against established Supreme Court precedent. Something that is knowingly exposed to the public will not receive constitutional protection.[xxviii]  The D.C. circuit incorrectly concluded that the totality of the defendants movements were not knowingly exposed to the public, but the fact is that they were indeed exposed.  The only difference being that the defendant’s movements were obtained through a GPS device rather than through the tracking efforts of a physical law enforcement official.[xxix]

The Maynard court qualified “exposed to the public” as not merely what “another person can physically and may lawfully do but rather what a reasonable person expects another might actually do.”[xxx]  Using this rationale the D.C. Circuit held that the whole of a person’s movements over the course of a month is not actually exposed to the public because a person would not reasonably expect a stranger to observe all the movements undertaken in a one-month span.[xxxi]  The likelihood is just too remote.  However, “attempting to tie improbability to illegality is inappropriate in light of several Supreme Court Fourth Amendment decisions concerning new technology.”[xxxii]  Moreover, with the continued proliferation of GPS devices – now even available in most cellular phones, few could argue, “that society is completely unaware of the power of these devices.”[xxxiii]  The Supreme Court has not adopted a probabilistic approach to determine reasonable expectations of privacy, but rather has chosen to focus on “whether the nature of the information revealed is private and thus worthy of constitutional protection.”[xxxiv]

The approach adopted by the D.C. Circuit does not work.  The court doesn’t seem to have a problem with the use of the GPS device as much as it does with the aggregation of the information obtained.[xxxv]  Had the police used the GPS device to track the defendant for a single trip, the court would have probably concluded that its use was not a search under the Fourth Amendment.[xxxvi]  The court repeatedly stresses the personal and “intimate” details that a mosaic of information could reveal about an individual, however this same mosaic could be obtained through prolonged visual surveillance.[xxxvii]  The only difference being that it would cost the police and the State much more money to obtain the same type of evidence with prolonged visual surveillance than merely using a GPS device.

Part IV: Finding a workable accommodation between the needs of law enforcement and the interests protected by the Fourth Amendment

The Supreme Court has consistently reasserted, “the meaning of a Fourth Amendment search must keep pace with the march of science.”[xxxviii]  GPS technology and prolonged surveillance implicate the balancing of important policy issues with regards to the Fourth Amendment.  Generally, the Fourth Amendment implicates a balancing of privacy interests on the one hand and security interests on the other.

Clearly the use of a GPS device to track the movements of a suspected criminal on public streets should not come under the warrant requirement of the Fourth Amendment.  The tradeoff between privacy and security in these instances should favor security.[xxxix]  Again, law enforcement officials are merely tracking movements that are knowingly exposed to the public, which could similarly be tracked without the aid of a GPS device.  Furthermore, there is no evidence of police shooting GPS darts at random cars and tracking them to see if they catch someone engaged in illegal activity.  Random tracking and mass surveillance is of course a possibility, however, as of yet, there is no evidence of any attempts by law enforcement officials to engage in any type of urban monitoring scheme.[xl]

With the continued advancement of technology the tug of war between privacy and security will continue.  Today it involves the use of GPS to track criminal suspects and possibly random individuals and soon it will be over police drones roaming our airspace.  However, law enforcement officials do not envision the use of police drones or unmanned aircraft as a tool for keeping tabs on society but rather for evacuations, search and rescue, and tactical operations.[xli]

The use of technology for law enforcement purposes will help increase security, keep costs down, and lower the risks faced by police officers every day.  This is not to say that the courts and Congress should allow law enforcement officials to use all available technology, as they please – there have to be some limitations.  The Fourth Amendment is meant to strike a balance between privacy and security in our society. Allowing police to shoot GPS darts at random would probably help diminish crime in our streets but the sacrifice to privacy would be too great.  Requiring a warrant to utilize a GPS device to track a potential suspect could sacrifice police efficiency for only a minimal increase in privacy protection.  On the other hand simply requiring that police have a reasonable suspicion of criminal involvement to track a suspect on public streets with a GPS device could strike a healthy balance between privacy and security.

[i] U.S. Const. amend. IV.

[ii] See United States v. Karo, 468 U.S. 705, 712 (1984).

[iii] See Lopez v. United States, 373 U.S. 427, 441 (1963) (Warren, J., concurring).

[iv] See id.; United States v. Knotts, 460 U.S. 276 (1982).

[v] See Knotts, 460 U.S. at 283-84 (explaining that “there will be time enough then to determine whether different constitutional principles may be applicable” if the  “twenty-four hour surveillance of any citizen of this country without judicial knowledge or supervision” becomes an issue).

[vi] Florida v. Riley, 488 U.S. 445, 453 (1989) (O’Connor, J., concurring).

[vii] See Bond v. United States, 529 U.S. 334, 342 (2000) (Breyer, J., dissenting). (“In determining whether an expectation of privacy is reasonable, it is the effect, not the purpose, that matters.”) The purpose of a police officer in squeezing a person’s bag in an attempt to discover drugs is different from the intention of another passenger or driver squeezing the same bag in an effort to make space for other luggage. Most people with something to hide will be careful not to expose that something to law enforcement officials, however, they will not be anywhere as careful when it comes to exposing that something to other members of the public. Consequently, a “4th Amendment rule that turns on purpose could prevent police alone from intruding where other strangers freely tread.” Simply because a police officer’s actions are motivated by a law enforcement purpose should not restrict them from the same casual observations made by other members of the public. See id.

[viii] Rakas v. Illinois, 439 U.S. 128, 143 (1978).

[ix] See Katz v. United States, 389 U.S. 347, 361 (1967) (Harlan, J., concurring).

[x] See California v. Greenwood, 486 U.S. 35, 51-53 (1988) (Brennan, J., dissenting) (quoting various court decisions supporting the proposition that societal understandings and social custom will serve as the foundation for legitimate privacy expectations).

[xi] See Kyllo v. United States, 533 U.S. 27, 40 (2001) (establishing that the use of a device  not in general public use, to explore details of the home that would previously have been unknowable without physical intrusion, is a search).

[xii] See Knotts, 460 U.S. at 281-82.

[xiii] Riley, 488 U.S. at 453 (O’Connor, J., concurring).

[xiv] Id.

[xv] See Kyllo, 533 U.S. at 42 (Stevens, J., dissenting) (reiterating that although the use of the thermal imaging device had been found to be a search, the principle of Fourth Amendment jurisprudence remains the same – “What a person knowingly exposes to the public, even in his own home or office, is not a subject of Fourth Amendment protection.”); Greenwood, 486 U.S. at 40-41; Dow Chemical Co. v. United States, 476 U.S. 227, 235-36 (1986).

[xvi] Knotts, 460 U.S. at 284 (stating that “a principle rationale for allowing warrantless tracking of beepers in or on an auto, is that beepers are merely a more effective means of observing what is already public”).

[xvii] See United States v. Garcia, 474 F.3d 994, 996 (7th Cir. 2007) (“The Supreme Court has held that the mere tracking of a vehicle on public streets by means of a similar though less sophisticated device (a beeper) is not a search.”); United States v. Marquez, 605 F.3d 604, 609 (8th Cir. 2010) (“A person traveling via automobile on public streets has no reasonable expectation of privacy in his movements from one locale to another”); United States v. Pineda-Moreno, 591 F.3d 1212, 1217 (9th Cir. 2010) (concluding that the police in this case did not conduct an impermissible search of defendant’s car by monitoring its location with mobile tracking devices).

[xviii] See United States v. Maynard, 615 F.3d 544, 556-57 (D.C. Cir. 2010); United States v. Jones, 625 F.3d 766, 768. (D.C. Cir. 2010).

[xix] See Jones, 625 F.3d at 769-70. (referring to the GPS device capability of capturing large amounts of information, which then allow law enforcement officials to consolidate the data into a pattern that might reveal private information of a suspect).

[xx] Id. at 769.

[xxi] United States v. Sparks, 2010 WL 4595522, 8 (D. Mass. 2010).

[xxii] See Maynard, 615 F.3d at 568.

[xxiii] Id. at 558.

[xxiv] Katz, 389 U.S. at 351.

[xxv] See Knotts, 460 U.S. at 281-82.

[xxvi] See id.

[xxvii] See Maynard, 615 F.3d at 561-62 (explaining that the amount of information obtained through prolonged surveillance – the aggregation of many slices of information may reveal a “mosaic” or an intimate picture of life that an individual wishes to keep private).

[xxviii] See Knotts, 460 U.S. at 281-82.

[xxix] See Garcia, 474 F.3d at 997.

[xxx] See Maynard, 615 F.3d at 559.

[xxxi] See id. at 560.

[xxxii] See Sparks, 2010 WL 4595522 at 7 (citing Supreme Court precedent to support this proposition); United States v. Jacobson, 466 U.S. 109, 122 (1984) (“The concept of an interest in privacy that society is prepared to recognize as reasonable is, by its very nature, critically different from the mere expectation, however well justified, that certain facts will not come to the attention of the authorities.”); The probability of a government agent going through someone’s trash or renting an airplane to conduct aerial surveillance is similarly remote as continued surveillance with a GPS device, yet these acts stand firmly outside the reach of the Fourth Amendment. See Greenwood, 486 U.S. 35; California v. Ciraolo, 476 U.S. 207 (1986).

[xxxiii] See Sparks, 2010 WL 4595522 at 7.

[xxxiv] See id. at 7. (citing Orin S. Kerr, Four Models of Fourth Amendment Protection, 60 Stan L. Rev. 503, 512 (2007)).

[xxxv] See Jones, 625 F.3d at 769.

[xxxvi] See Maynard, 615 F.3d at 558 (distinguishing between what is exposed during a single journey in a car and what could possibly be exposed during multiple journeys over the course of a month); Jones, 625 F.3d at 769 (“Presumably, had the GPS device been used for an hour or perhaps a day, or whatever period the panel believed was consistent with a normal surveillance, the evidence obtained could have been admitted without Fourth Amendment problem.”).

[xxxvii] See Jones, 625 F.3d at 769.

[xxxviii] Id. (citing Katz, 389 U.S. 347).

[xxxix] See Garcia, 474 F.3d at 998.

[xl] See id.

[xli] See Peter Finn, Domestic Use of Aerial Drones by Law Enforcement likely to Prompt Privacy Debate, The Wash. Post (Jan. 23, 2011),