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Digest Comment - New Technologies and the Fourth Amendment

Commentary Notes First Amendment

Editorial Policy

New technologies have made types of searches possible which could never have been envisioned when the Fourth Amendment was proposed to prohibit unreasonable search and seizure. With remote listening, infrared imaging, and, now, wireless technologies, it is possible to detect movements of people within buildings with no discernible physical impact on the surveilled person’s life.[ii] Are remote searches reasonable? Do they require a warrant?[iii] In my opinion, courts should treat these sorts of remote detection techniques (“surveillance”) as searches subject to the Fourth Amendment’s requirement of reasonableness.

The Fourth Amendment to the U.S. Constitution expressly guaranties that:
"The right of the people to be secure in their persons, houses, papers, and effects, against unreasonable searches and seizures, shall not be violated, and no Warrants shall issue, but upon probable cause, supported by Oath or affirmation, and particularly describing the place to be searched, and the persons or things to be seized."

The Fourth Amendment was incorporated by the Fourteenth Amendment to apply directly to the states, even though many protections against search and seizure at state common law were more extensive than the Fourth Amendment.[iv] The general rule is that the Fourth Amendment’s prohibition of unwarranted searches does not apply where there is no reasonable expectation of privacy.[v] That leads to the question of when a person has reason to believe that he or she is “in private” as opposed to “in public”. This will depend both on the facts of the case and on social reality.[vi] For example, different cultures within the United States have different senses of what is “public” and what is “private”, and those senses are constantly evolving.[vii] However, one bright line stands out: searches of homes without warrants are presumptively unreasonable because “[a]t the very core [of the Fourth Amendment] stands the right of a man to retreat into his own home and there be free from unreasonable governmental intrusion.” [viii]

At first, this might seem to offer significant protection. However, when we ask “what is a search,” we discover several activities that are not in fact considered “searches” even in the context of one’s own dwelling. In one case, the court decided that helicopter overflights making naked-eye observations of concealed marijuana crops did not violate the “reasonable expectation of privacy” and thus were not subject to the Fourth Amendment’s protections.[ix] In another case, an officer’s observation of marijuana plants growing in a backyard was held not to be a search under the Fourth Amendment when the observation was made from the defendant’s publicly accessible driveway.[x] Essentially, anything in plain view from a publicly accessible vantage point is not subject to the Fourth Amendment.[xi]

What then of the new technologies which enable unique and innovative forms of search and surveillance? Generally speaking, the U.S. Supreme Court limits application of the Fourth Amendment to new technologies.[xii] Given the permissive attitude toward searches of the exterior of houses and searches in the context of modern inventions such as computers and data media, one might expect the Court to allow the use of new technologies to search personal dwellings as well. That does not seem to be the case. The U.S. Supreme court has answered fairly clearly in this regard, stating:

[I]n the case of the search of the interior of homes -- the prototypical and hence most commonly litigated area of protected privacy -- there is a ready criterion, with roots deep in the common law, of the minimal expectation of privacy that exists, and that is acknowledged to be reasonable. To withdraw protection of this minimum expectation would be to permit police technology to erode the privacy guaranteed by the Fourth Amendment. We think that obtaining by sense-enhancing technology any information regarding the interior of the home that could not otherwise have been obtained without physical ‘intrusion into a constitutionally protected area,’ constitutes a search -- at least where (as here) the technology in question is not in general public use.”[xiii]

Likewise, police monitoring of electronic transmissions from within a house violates the Fourth Amendment because the inside of a house is a “location not open to visual surveillance.”[xiv] A similar analysis holds for “bugs” which record and/or transmit audiovisual data – they cannot be placed inside a dwelling without a warrant.[xv]

The problem remains of how to resolve apparently contradictory tendencies in the cases which result from the fact-intensive inquiry needed to determine whether an expectation of privacy is “reasonable” and the circular character of that inquiry – reasonable expectations are created by court decisions as well as reflected in them. A partial resolution results from focusing on a bright line test: we can somewhat reconcile the different results between remote sensing devices used to search dwellings, where the Fourth Amendment applies, and computer technologies generally, where it often does not, by focusing on the particular status of the home as each person’s secure refuge. Even that is of little use given the ideas of “curtilage”[xvi] and “open fields”[xvii] where the “plain view” doctrine permits warrantless searches. This particular divergence most likely cannot be usefully explained in “economic” terms as somehow “efficient”.

How, then, are we to understand the Fourth Amendment? Can we impose any rationality on these contrary tendencies? They reflect the basic struggle between the State as guardian against criminality and the justified fear of tyranny. The problem facing us all is: how can the State, the most powerful actor of all, be prevented from aggrandizing even more power with each introduction of new technology? Recourse to the Framers’ intent as to the meaning of “search” is of little help here when remote sensing technologies did not exist in 1789, especially since cultural understandings like the “reasonable expectations of privacy” evolve over time.

Currently, the struggle over the meaning of the Fourth Amendment is often cast as one more example of the struggle between “individual rights” versus “collective powers”[xviii] with a balancing[xix] of various competing interests via a multitude of factors.[xx] That miscasts the issue. “Rights” of individuals and “powers” of the State are both emanations of State power because rights are enforced by courts and police. The inevitable and impossible problem of self-limitation of the State, of the renunciation of the State to power despite the desire of factions to seize state power and aggrandize their own power[xxi] is not a problem of “rights” versus “powers”. It is a problem of self-limitation of the State, by the State.[xxii] However, multi-factor interest balancing tests are too vague and manipulable to provide the essential protections needed against state power.

The conflict between “individual rights” and “collective state powers” is currently methodologically analyzed via “balancing,” a term which in American jurisprudence has more than one meaning[xxiii] and can refer to either a multi-factor interest analysis[xxiv] (e.g., in the Fourth Amendment) or, instead, to what in the European Union[xxv] is referred to as “proportionality”[xxvi] (e.g., in equal protection and due process analysis). Multi-factor interest balancing tests are rightly criticized as arbitrary and potentially capricious judicial fiat.[xxvii] How does the court decide which factors are chosen and what weight is assigned to them? In contrast, the proportionality test provides much greater legal certainty.

The proportionality inquiry is more exacting than ad hoc multi-factor interest balancing. Proportionality refers to means-end rational review[xxviii] with strict scrutiny for suspect classes[xxix] and requires the examination of:

1) the means chosen by the State (are they necessary?)

2) the ends to be attained (are they legitimate?)

3) the relationship between the means and ends (is there a rational relationship between the two?);

4) the application of strict scrutiny (i.e., is the invasion of the private fundamental right by the public power done via the least restrictive means?[xxx])

Fourth Amendment jurisprudence is circular,[xxxi] confused,[xxxii] and often criticized[xxxiii] because determining and balancing competing interests is vague and manipulable. As a jurist, the only practical way to proceed is through fact-intensive analysis of the individual case to try to find out what is a “reasonable expectation of privacy” in the given factual context. But, from the perspective of legal theory, the only solution is to understand that the problem is inevitable and irresolvable because the issue is miscast both theoretically and methodologically. Theoretically, the conflict is not between (individual) “rights” versus (collective) “powers”.[xxxiv] Rather, the conflict is between the State as guardian versus the State as tyrant because both “rights” and “powers” are creations of the State. The State’s invasions of freedoms should thus be regarded with great distrust because of the tendency to tyranny. [xxxv] Interpretations of the text, context, structure, history, and intent of the law must be made with this principle of distrust of state power as a guide.[xxxvi] Doubtful cases should be resolved by a presumption against the State and in favor of the people. That is what is meant by the phrase “limited self-government”[xxxvii] – a democratic minimal state.[xxxviii]

Will the court’s currently confused “interest balancing” approach in the Fourth Amendment context[xxxix] ever solve the problem of what is a “search” and when it is “reasonable”? No, because the test itself is flawed and uncertain. A proportionality test would better protect individual freedoms. Is the invasion of the fundamental right to privacy a necessary means to a legitimate end? Is the infringement of this fundamental right the least invasive possible? In many cases, searches are a necessary means to the legitimate end of public security. However, because the invaded right is fundamental the permissibility of such searches should be subject to strict scrutiny – proportionality stricto sensu.

The State should be able to undertake non-invasive “remote” searches via new technology without triggering the State’s liability in tort for breach of privacy due to the absence of monetary damages. Without a warrant, however, such evidence ought to be inadmissible in court. This approach is sensible because the people have a clear interest in discreet surveillance of criminals, whether terrorists or drug dealers. At the same time, the people have a clear interest in privacy and in avoiding the risk of a tyrannical government.[xl] Electronic remote searches are not invasive or intrusive. They are not outrageous. However, to be admitted into court there must be a good reason for such search to have been undertaken in the first place.

New technologies are here and the problem will not disappear – unlike your liberties, or for that matter, criminals. Justice Scalia has already noted the flawed nature of open-ended multi-factor interest balancing.[xli] It is likely that the U.S. doctrine of multi-factor interest balancing will merge into the globalizing legal concept of proportionality because interest balancing is vague and uncertain whereas proportionality is much better defined. New technologies are both a vector of this globalization of law leading to normative convergence and a subject of it.

[i] Dr. Engle works as a research assistant to Duncan Kennedy at Harvard Law School and as an editor for various law journals at Harvard. He can be reached at

[ii] Kim Zetter, Wireless Network Signals Produce See-Through Walls, WIRED.COM, Oct. 2, 2009,

[iii] See generally, Richard S. Julie, High-Tech Surveillance Tools and the Fourth Amendment: Reasonable Expectations of Privacy in the Technological Age, 37 Am. Crim. L. Rev. 127 (2000) (describing the law of search and seizure with respect to new technologies).

[iv] Thomas Y. Davies, Correcting Search-and-Seizure History: Now-Forgotten Common-Law Warrantless Arrest Standards and the Original Understanding of “Due Process of Law”, 77 Miss. L.J. 1 (2007) (explaining that common law protections against warrantless search and seizure were more extensive than Fourth Amendment guaranties).

[v] See, e.g., California v. Greenwood, 486 U.S. 35, 37-38 (1988) (finding no reasonable expectation of privacy in garbage because “[i]t is common knowledge that plastic garbage bags left on or at the side of a public street are readily accessible to animals, children, scavengers, snoops, and other members of the public.”). So for example, evidence obtained from a homeless person rummaging through a dumpster would be admissible in court.

[vi] Orin S. Kerr, The Fourth Amendment and New Technologies: Constitutional Myths and the Case for Caution, 102 Mich. L. Rev. 801 (2004) (arguing that the admissibility of new technologies in searches should be determined by the legislature, not the judiciary).

[vii] See generally, Steven Penney, Reasonable Expectations of Privacy and Novel Search Technologies: An Economic Approach, 97 J. Crim. L. & Criminology 477 (2007) (explaining the reasonable expectation standard in the context of new technologies).

[viii] Silverman v. United States, 365 U.S. 505, 511 (1961).

[ix] California v. Ciraolo, 476 U.S. 207, 209 (1986); see also Florida v. Riley, 488 U.S. 445, 448–51 (1989).

[x] United States v. Hatfield, 333 F.3d 1189, 1198 (10th Cir. 2003).

[xi] California v. Ciraolo, 476 U.S. 207, 213 (1986).

[xii] See Daniel J. Solove, The Digital Person: Technology and Privacy in the Information Age 202 (2004).

[xiii] Kyllo v. United States, 533 U.S. 27, 34 (2001) (internal citations omitted).

[xiv] United States v. Karo, 468 U.S. 705, 714 (1984).

[xv] Berger v. New York, 388 U.S. 41 (1967).

[xvi] United States v. Dunn, 480 U.S. 294 (1987) (applying a multi factor test to determine whether an area is “curtilage”).

[xvii] Oliver v. United States, 466 U.S. 170 (1984) (explaining the “open fields” doctrine with respect to the Fourth Amendment); United States v. Vankesteren, No. 08-4110, 2009 U.S. App. Lexis 183 (4th Cir. 2009) (allowing evidence from a video surveillance device placed in an “open field”).

[xviii] “Moderates and conservatives argued that because all the courts could do was balance rights against powers, or rights against rights, they had no specifically legal basis for overruling legislative judgments.” Duncan Kennedy, The Critique of Rights in Critical Legal Studies, in Left Legalism/Left Critique (Wendy Brown & Janet Halley eds., 2002).

[xix] Whether a search is reasonable "is judged by balancing its intrusion on the individual's Fourth Amendment interests against its promotion of legitimate governmental interests." Delaware v. Prouse, 440 U.S. 648, 654 (1979).

[xx] See Comm. on the Judiciary, House of Representatives v. Miers, No. 08-0409 (D.C. 2008) (citing Gonzaga Univ. v. Doe, 536 U.S. 273, 283 (2002)).

[xxi] See James Madison, Federalist #10 (1787).

[xxii] See Gunther Teubner, Self-subversive Justice: Contingency or Transcendence Formula of Law?, 72 Mod. L. Rev. 1 (2009).

[xxiii] See Lawrence Solum, Legal Theory Lexicon: Balancing Tests, Legal Theory Blog (August 23, 2009).

[xxiv] See id.; T. Alexander Aleinikoff, Constitutional Law in the Age of Balancing, 96 Yale L.J. 943 (1987).

[xxv] See J.H. Gerards, Proportionality review in European law, IVR Encyclopaedia of Jurisprudence, Legal Theory and Philosophy of Law (2009).

[xxvi] E. Thomas Sullivan & Richard S. Frase, Proportionality Principles in American Law: Controlling Excessive Government Actions (2009).

[xxvii] Lawrence Solum, A Law of Rules: A Critique and Reconstruction of Justice Scalia's View of the Rule of Law, APA Newsletters, Forthcoming (Discussing discussing Justice Scalia’s critique of multi-factor balancing tests); District of Columbia v. Heller, 128 S. Ct. 2783 (2008)554 U.S. ___ at 62.

[xxviii] Mculloch v. Maryland, 17 U.S. 316, 356–57 (1819) (“The court, in inquiring whether congress had made a selection of constitutional means, is to compare the law in question with the powers it is intended to carry into execution; not in order to ascertain whether other or better means might have been selected, for that is the legislative province, but to see whether those which have been chosen have a natural connection with any specific power; whether they are adapted to give it effect; whether they are appropriate means to an end.”) (emphasis added).

[xxix] See Korematsu v. United States, 323 U.S. 214 (1944).

[xxx] See Id.

[xxxi] Ian James Samuel, Warrantless Location Tracking, 83 N.Y.U. L. Rev. 1324, 1340 (2008).

[xxxii] See Christopher Slobogin, Technologically-Assisted Physical Surveillance: The American Bar Association's Tentative Draft Standards, 10 Harv. J.L. & Tech. 383, 401 (1997) (contending that the courts apply a multi-factored analysis to decide whether government conduct violates a reasonable expectation of privacy, and then concluding that “many of the factors that courts consider... are of dubious value”).

[xxxiii] See Id.

[xxxiv] See generally, Duncan Kennedy, Toward an Historical Understanding of Legal Consciousness: The Case of Classical Legal Thought in America, 1850–1940, 3 Res. in Law & Soc. 3 (1980).

[xxxv] See James Madison, Federalist #10 (1787).

[xxxvi] Charles Kelso & Randal Kelso, The Path of Constitutional Law (2007).

[xxxvii] “The powers delegated by the proposed Constitution to the federal government are few and defined.” James Madison, Federalist #45 (1788).

[xxxviii] See James Madison, Federalist #45 (1788); Alexander Hamilton, Federalist  #83 (1788).

[xxxix] Professor Donald Dripps, Will the real Fourth Amendment please stand up?, in Trial (1995).

[xl] For an example of governmental overreach see Ryan Singe, FCC’s Warrantless Household Searches Alarm Experts, WIRED.COM, May 21, 2009,

[xli] Bendix Autolite Corp. v. Midwesco Enter., 486 U.S. 888 (1988) (dissent); Vernonia Sch. Dist. 47J v. Acton, 515 U.S. 646 (1995).