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Fourth Amendment

Reconciling Katz and the Fourth Amendment Text

Some people think the Katz "reasonable expectation of privacy" test is hard to reconcile with the text of the Fourth Amendment. Here's why I think they're wrong.


Monday was the 50th Anniversary of Katz v. United States, the Supreme Court's big decision on the Fourth Amendment's "search" test. I often hear that Katz created a vague and non-textual notion of "privacy" that is unmoored from the text. But it seems to me that it's easy to reconcile Katz with the text of the Fourth Amendment. To be sure, Katz was decided in an era when text and history wasn't particularly important. If you follow what opinions say on their face, rather what they actually do, Katz seems weirdly inattentive to the text. But if you focus on what the Katz framework actually does, it seems to me, the decision is readily reconcilable with the text.

This post will explain why.

Let's start, appropriately enough, with the text:

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 second part of that, often called the warrant clause, is pretty narrowly about search warrants. So it's the first part that matters more broadly. That first clause of the text recognizes a right of the people against "unreasonable searches and seizures" in "their persons, houses, papers, and effects."

If you're a textualist, you would break down the Fourth Amendment text into four questions:

(1) Is the thing to be protected a "person, house, paper or effect"?

(2) If the answer is yes to (1) above, is it the person, house, paper or effect of the individual claiming the constitutional violation (that is, is it "their" person, house, paper or effect or someone else's)?

(3) If the answer is yes to (2) above, was the individual's person, hour, paper or effect "searched" and/or "seized"?

(4) If the answer is yes to (3) above, was the search and/or seizure "unreasonable"?

So that's the text. If you follow Fourth Amendment doctrine, you know that it tends to combine Questions 1, 2, and 3 into a single question: Was the government action a search or seizure? And then the Katz test for a what is a search, from Justice Harlan's concurring opinion in Katz, is often expressed as a two-part test: First, did the person exhibit a subjective expectation of privacy? Second, if so, was that expectation of privacy an expectation that society is prepared to accept as reasonable?

At first blush the Katz test might seem contrary to the text, or at least not particularly related to it.

But here's the thing: It's pretty easy to restate the Katz test using the constitutional text. The reason is that Katz preserved all four textual questions. At times it used non-textual labels for their concepts. But Katz uses the same concepts that you encounter based on a close reading of text.

Recall the facts of Katz. The FBI taped a microphone to the top of a public phone booth Katz used to place illegal bets. When Katz went into the phone booth, closed the door, and paid for the call, the FBI turned on the microphone and recorded his side of the call. In his concurrence, later adopted by the Court, Justice Harlan identified the three major holdings of the majority opinion:

I join the opinion of the Court, which I read to hold only (a) that an enclosed telephone booth is an area where, like a home, Weeks v. United States, 232 U. S. 383, and unlike a field, Hester v. United States, 265 U. S. 57, a person has a constitutionally protected reasonable expectation of privacy; (b) that electronic as well as physical intrusion into a place that is in this sense private may constitute a violation of the Fourth Amendment; and (c) that the invasion of a constitutionally protected area by federal authorities is, as the Court has long held, presumptively unreasonable in the absence of a search warrant.

These three holdings match up with three of the four textual steps. Holding (a), that an enclosed telephone booth is an area protected by the Fourth Amendment, was in textual terms saying that an enclosed telephone booth (like a home but unlike an open field) was a Fourth Amendment "effect." That is, it was answering Question 1, identifying the spaces or things protected by the Fourth Amendment.

Holding (b), that electronic as well as physical intrusion can violate the Fourth Amendment, was in textual terms saying that an electronic intrusion can be a "search" of the Fourth Amendment "effect" of the phone booth. It was answering Queston 3, whether the effect was searched or seized. And holding (c), that a warrant was required, was in textual terms (as Justice Harlan recognized) saying that a search or seizure is unreasonable without a warrant. That's obviously the Queston 4 reasonableness iquiry

The only step explicitly missing in Harlan's summary of Katz's holding was the Question 2 inquiry into whether the search that occurred was of Mr. Katz's own effects or someone else's effects. But that was made clear in the majority opinion, in what Justice Harlan called the "critical" point of the majority opinion: It was "a person in a telephone booth" who "may rely upon the protection of the Fourth Amendment." As Justice Stewart wrote for the majority:

One who occupies it, shuts the door behind him, and pays the toll that permits him to place a call is surely entitled to assume that the words he utters into the mouthpiece will not be broadcast to the world.

Katz, 389 352. In Justice Harlan's words, during that time the phone booth became a "temporarily private place" for the caller. This is the Question 2 point. The phone booth was not just an "effect" in the abstract, but it was the constitutional "effect" of the person who occupied the phone booth and paid the toll during the period of the call.

The upshot of all of this is that we can pretty easily interpret Katz using the constitutional text. In textual terms, Katz held that the phone booth was an "effect" that the Constitution protects (Question 1); that when callers occupy the booth and pay the toll, the phone booth becomes "their" effect (Question 2); that listening in from a microphone taped to the top of the phone booth was a "search" of that effect (Question 3); and that the search of their effect was "unreasonable" without a warrant (Question 4).

But wait, you may be wondering, what about Justice Black's dissent? Justice Black dissented on textualist grounds, after all. But he did so on a really narrow point. Justice Black focused on the use of the recording device instead of its installation. In his view, turning on the microphone to capture Katz's voice was not a "search" or "seizure" of any "persons, houses, papers, and effects." Here's the key passage:

The first clause protects "persons, houses, papers, and effects against unreasonable searches and seizures. . . ." These words connote the idea of tangible things with size, form, and weight, things capable of being searched, seized, or both. The second clause of the Amendment still further establishes its Framers' purpose to limit its protection to tangible things by providing that no warrants shall issue but those "particularly describing the place to be searched, and the persons or things to be seized." A conversation overheard by eavesdropping, whether by plain snooping or wiretapping, is not tangible and, under the normally accepted meanings of the words, can neither be searched nor seized.

Note that Justice Black assumed that the "persons, houses, papers, and effects" had to be the conversation that was recorded, not the phone booth. The overheard conversation wasn't a person, house, paper, or effect, so to Justice Black it made no sense to say that eavesdropping was protected by the Fourth Amendment. But as far as I can tell, Justice Black never addressed the more obvious textual basis for the majority's decision: That the phone booth was the "efffect," and that the installation and use of the microphone was the "search" of that effect. From that perspective Katz was something like United States v. Jones, the GPS case, in which the majority concludes that installing the device was a "search" of the "effect" that was the car Jones drove while the concurring opinions focus on use of the GPS device to collect location information.

Now some of you may be reading this long post and thinking, how do you deal with the "reasonable expectation of privacy" test? From a textual perspective, I think that test is best understood as just a way to express when a person's "effects" are "searched." A person has a reasonable expectation of privacy in a place or thing when that thing is the person's "effect" (or their house, person, or papers, of course, but that is usually an easier case). When government action infringes that reasonable expectation of privacy, that effect is "searched," at least unless a person reveals that place or thing to others and therefore gives an implied license to search it (which you can equivalently see as not manifesting a subjective expectation of privacy or else as an implied license under Florida v. Jardines).

If it seems nontextual to rely on a vague phrase like "reasonable expectation of privacy" to identify what counts as a "search" of an "effect," it helps to recall a bit of Fourth Amendment history. As I detailed in The Curious History of Fourth Amendment Searches, courts before Katz really struggled to say what counted as a search. The early cases on the meaning of "searches" used an uncertain mix of privacy concepts and analogies to property without ever stating a particular test for what made something a search. Indeed, as far as I can tell, the first effort to articulate what makes something a search was Justice Harlan's effort to summarize "the rule that has emerged from prior decisions" in his Katz concurrence. This was the so-called "Katz test" that focuses on expectations of privacy.

But Justice Harlan's test was not designed to make vague notions of privacy the core of the Fourth Amendment, it seems to me. It is true that the test Justice Harlan articulated included the word "privacy." But I think Justice Harlan had something more specific in mind. The puzzle in Katz was which kinds of spaces could receive Fourth Amendment protection from searches. Homes, taxicabs, and rented hotel rooms could, the precedents indicated. Open fields could not. The specific question in Katz, as articulated by Justice Harlan at the beginning of his concurrence, was how to treat a phone call inside a public phone booth with glass walls and a door. Was that more like a rented hotel room (protectable) or an open field (not protectable)?

As I understand Harlan, the idea of what expectations "society is prepared to recognize as reasonable" was not some sort of free-floating notion but rather a more specific idea. Some places were treated like the home and others were not. How do you determine what is treated like the home? What's the line? It wasn't the common law of property, a standard that the Court had never embraced and indeed had long ago rather harshly dismissed. Rather, it was an idea that some places were broadly understood by people as home-like. And that was the case with a public phone booth in Katz. When a person entered the booth, shut the door, and paid for their call, the booth became understood as their booth for the duration of the call. It was therefore protectable under the Fourth Amendment.

From this perspective, Justice Harlan's test could be readily articulated using the Fourth Amendment text. The reasonable expectation of privacy test is just asking if the government action is a search of the individual's "person, houses, papers, or effects." The idea of what "society is prepared to recognize" really goes to what is considered a person's "effects." A public phone booth was among the caller's "effects" during the call; it was a temporarily rented space that became theirs for that brief time window.

This view also explains why the move to a trespass-property view of "searches" in Jones doesn't make much (if any) difference to what the Fourth Amendment protects. It changes the black-letter law a lot. But as I discussed in Curious History, it's not clear what if any results it changes. The Katz framework is best understood as doing the same work that an explicitly textual approach does. It uses different words, yes. But properly understood, it seems to me, it's doing the same basic work.