How should the Fourth Amendment’s original meaning be applied to modern technology that was not in existence at the time of the Amendment’s enactment? Many commentators believe this type of question problematic to answer. As Justice Alito quipped some years ago at oral argument, “I think what Justice Scalia wants to know is what James Madison thought about video games.” But in the case of the Fourth Amendment, there is a disciplined way to engage in this inquiry. Here I discuss how the matter should work with respect to two recent cases—Riley v. California (the search of cell phones when a person is arrested) and Kyllo v. U.S. (the use of heat sensors to determine the temperature inside a home—as a means of discovering whether illegal pot is being grown there).
In a prior essay, I noted that the Fourth Amendment to the Constitution guarantees “the right of the people to be secure in their persons, houses, papers, and effects, against unreasonable searches and seizures.” Unfortunately, the Supreme Court has followed neither the text nor the original meaning of the Amendment. In Katz v. United States, the Court held that whether a government action constitutes a search depends on whether it interferes with a reasonable expectation of privacy of an individual. But the Amendment does not speak about privacy or define searches by reasonable expectations of privacy.
Instead, the Amendment simply speaks of searches, which had an ordinary meaning at the time of looking “over or through things.” And the covered searches were limited to searches of “persons, houses, papers, and effects.” So whether something is a search is not a matter of reasonableness, but of whether one of those four things is examined.
The text of the Amendment does make reasonableness relevant, but only to something that has already been classified as a search. It is unreasonable searches that are prohibited. And the reason that is referred to here is the reason of the common law. Thus, the Amendment’s prohibition on unreasonable searches simply asks whether such searches were allowable under common law.
In cases where the existing common law did not provide a clear answer, as with new technology, courts must determine the content of the common law right by deciding the case as a common law judge at the time would have—by considering the existing precedents and values at the time.
Let me then apply this approach to Riley and Kyllo.
In Riley, the police arrested Riley and sought to search his cell phone without a warrant under the “search incident to an arrest” exception. Under this exception, the police are allowed to search evidence they uncover when making an arrest without having to get a warrant. While this doctrine would normally cover personal property on the arrested person, the Court held that the doctrine could not be used to search a cell phone. The Court reached this result by invoking modern nonoriginalist precedents and balancing the legitimate government interests with an individual’s privacy interests.
While the Supreme Court applied nonoriginalist precedents, what would an originalist analysis look like? First, it seems clear that the police are attempting to search of an “effect” (since the phone is movable personal property) and thus within the scope of the Fourth Amendment’s protection. The next question is whether the search is a reasonable one. Since the search incident to arrest exception to warrants was part of the common law, originalist analysis suggests that it accords with the Amendment’s original meaning. Searches pursuant to that common law doctrine appear to have been justified on the grounds that the Supreme Court mentioned in Riley—to prevent destruction of evidence and to protect against violence from the person arrested.
The question, then, is how a common law judge at the time would have answered the question whether search of a cell phone fell under the search incident to arrest exception. And while some people will regard this question as unanswerable, I do not. If the reason for the exception (preventing destruction of evidence and protection against violence from the person arrested) is accurate, and if the common law judge understood how cell phones work (which we must assume to answer the question correctly), then I believe there is a strong case that the common law judge would not have extended the search incident to arrest exception to cell phones. Put differently, a common law judge would have recognized that cell phones were quite different than other materials on the suspect’s person and therefore should be treated differently.
The reason is that the values underlying the earlier cases apply differently to cell phones. While preventing destruction of evidence and protecting against violence from the person arrested are important concerns as to traditional property on the person of the arrested individual, they are far less important as to a cell phone. Once the cell phone has been seized (but not searched), the possibility that it could cause harm to the police or that the evidence would be destroyed is quite low.
By contrast, while privacy interests are weakly implicated in the ordinary situation, since there is only a limited amount of information that can be gleaned from non-digital materials on a person, (even from a wallet), privacy interests are strongly implicated by the search of a cell phone, which has an enormous amount of information about a person, including possibly large collections of pictures, videos, text messages, bank information, emails, and personal files.
There is, of course, no certainty that judges at the time would have viewed the matter in this way. It requires us to ask how they would evaluate a type of technology that was completely unknown at the time. But there is little reason to believe that they would have evaluated these basic facts about cell phones any differently than modern judges. If the values identified were the basis of the search incident to arrest exception, as scholars assert, then this does not seem like a problematic judgment.
What is interesting here is that this analysis resembles the Supreme Court’s decision in Riley, even though that decision followed nonoriginalist precedent. This is not an isolated example. One of the things that I have learned over my years as an originalist scholar is that the original meaning of a provision is often closer to the nonoriginalist position than I would have imagined. There is no necessary connection here; it just happens more often than one might expect.
Now, let me turn to the other Supreme Court case, Kyllo v. U.S., where the police used a heat sensor, along with other information, to obtain a warrant. The question is whether aiming the infrared heat sensor at the outside walls of a home amounted to a search of the home. Justice Scalia wrote the opinion, but applied the nonoriginalist Katz reasonable expectations of privacy test. He concluded that individuals had a reasonable expectation of privacy against use of the heat sensors to obtain information from a house.
While Scalia applied a nonoriginalist test, what would the originalist analysis look like? The first question is whether this is a search of a house. If it is search, it is certainly of a house. But is it a search? Here the analysis is a little complicated but in the end seems to suggest there is a search. One possibility is that examining the outside walls of a house is a search because that is “examining” part of the house and that accords with the ordinary meaning of the term at the time. It might be argued, however, that this is not a search because the outside of the house is in public and simply looking at something in public is not a search. But even if one accepts this latter argument, one might still conclude that it is a search because the police are using special equipment to examine the outside of the house. Thus, what they are examining is not open to all people in the public.
The next question, then, is whether the search is unreasonable. One must ask how a common law judge at the time would have decided the case. Since thermal imaging was not employed at the time of the Constitution, one must engage in an independent analysis. Once again, the nonoriginalist arguments used by the majority and dissent seem quite helpful.
That the thermal imaging reveals information that is occurring inside the home seems to strongly indicate that it is an unreasonable search absent a warrant. If a common law judge would have placed strong emphasis on the importance of privacy within the home, which seems quite likely, that is a strong argument for the unreasonableness of the search. There is a moderately strong argument, however, on the other side. The thermal imaging only revealed very rudimentary information about what was occurring inside the house—information about the heat being emitted. While some judges might have used this fact to conclude that the thermal imaging is not unreasonable, my judgement is that it is more likely that a common law judge of the time would view the thermal imaging as being an unreasonable search, since it was an infringement on an area that was traditionally protected.
In the end, this analysis shows that a proper understanding of the Fourth Amendment can accommodate modern technology, even though that technology was not known at the time. The analysis does require a limited common law type reasoning, but that is what the original meaning requires.