Because I teach criminal procedure but write mostly about the First Amendment (I do have some Fourth Amendment pieces), I read Fourth Amendment cases differently from First Amendment cases. The Supreme Court’s decision in Carpenter v. United States is exciting because it holds that government use of cell site data to determine a defendant’s location over a period of seven days is a search, requiring probable cause and a warrant. Perhaps even more exciting, Carpenter promises to be a joy to teach.
There are so many reasons why Carpenter will be a great teaching case. Skeptical (and anxious) students prefer precise answers to thorny legal questions, but also need to be pushed to recognize a case’s inherent ambiguities and open questions. The majority and dissenting opinions give the reader snippets of clarity but also plenty of work to do to find coherence with underlying principles for future application. The case also straddles the line between “third-party doctrine” cases, so it recruits line-drawing and analogical reasoning skills. Plus, fundamentals of the doctrine are challenged by several Justices. The different opinions grapple with the relationship between property and privacy, and the Court also wades into confused areas like the connection between the Fourth Amendment and the subpoena power. This case has everything, even a lesson in cell phone technology!
Some of the most pedagogically interesting aspects of Carpenter:
- The framework: Chief Justice Roberts rightly sticks to the Fourth Amendment framework of (1) is this a search and (2) is it reasonable. Plus, he affirms that Fourth Amendment searches generally require probable cause and a warrant to be reasonable. His majority opinion even chides Justice Kennedy’s dissent for conflating the two questions (something students new to the Fourth Amendment also tend to do). Kennedy believes that because the cell site data was obtained based on a subpoena of phone companies’ records, subject to judicial authorization, the probable cause standard need not govern this case. But, if obtaining a defendant’s locations using cell site data is a search, invading a legitimate expectation of privacy, there’s little reason why the probable cause standard would not be required to render the search reasonable.
- The third-party doctrine: Most of the previous cases hold that information given to a third party is no longer private, and thus not a search protected by the Fourth Amendment. (Your garbage on the curb is not even private, since children can rummage through it.) Carpenter needed to be placed somewhere on the spectrum between Miller – which held that subpoenas of bank records are not a search because defendant had no legitimate expectation of privacy in information given to a third party (the bank) – and the notion that the government cannot subpoena Google for access to our email without probable cause. The basis for The Chief’s majority holding here is not entirely clear, and neither is his distinction between location information and credit card transactions, which are not protected by the Fourth Amendment against subpoenas of credit card companies. The majority seems to (1) find important that full-scale surveillance was disfavored during the Founding Era, (2) display a deep concern for the police’s increased ability to leverage technology to intrude upon people’s privacy (notice the multiple citations to Kyllo), and (3) rely on the fact that the location information subpoenaed was not part of a business transaction, unlike bank records and credit card information. Under the majority’s explicit reasoning, the fact that information is given to a third-party affects whether a defendant has a legitimate expectation of privacy, but does not overcome serious privacy interests.
- The relationship between privacy and property: The majority opinion entirely decouples the privacy-based and property-based rules determining when something is a search. Students can continue using either Katz (a search occurs when a legitimate expectation of privacy is invaded) or Jones (a search occurs when the government trespasses upon your property). These tests do not interact with each other under the majority’s reasoning. Justice Kennedy’s dissent would have property-based rules inspire the Katz test, allowing for more interconnectedness between the two tests. Justice Thomas, radically, would undo Katz’s hold on the doctrine entirely. He lodges valid criticisms against Katz’s privacy framework. Justice Gorsuch would relegate Katz to the margins and mostly use a Jones property-based theory (one he believes in actually rooted in “law”) and might also undo the entire third-party doctrine.
- The subpoena power: The interaction between the subpoena power and the Fourth Amendment has been messy since the Court began undermining Boyd. A subpoena is a “constructive search,” in that the police are not wading through a defendant’s home or effects, but that does not diminish a suspect’s Fourth Amendment privacy rights if those privacy rights exist (Justice Alito’s dissent takes issue with this). Subpoenas of businesses generally need not comply with the probable cause standard because corporations have diminished privacy interests under the Fourth Amendment. However, the subpoena of a business to obtain the private aspects of a person’s life requires probable cause and a warrant. Justice Roberts’s majority opinion ensures that the administrative state’s increasing use of the subpoena power to bypass Fourth Amendment standards will not continue unchecked. Justice Alito’s dissent, quite concerned with this opinion’s effect on the subpoena power, offers a nice history of compulsory process.
- The major open question: What if the government had sought less than seven days’ worth of location information? The Chief was not inclined to answer this question.
There is so much more to say about this case, but that’s exactly why it will be pedagogically rich.
(Cross posted on PrawfsBlawg.)