Author: Lior Strahilevitz & Matthew Tokson


Quick Reactions to Today’s Carpenter Oral Argument – Post 2

[Lior Strahilevitz (Chicago) and Matt Tokson (Utah) have been blogging about Carpenter v. United States all week.  Below are Matt’s thoughts about the Carpenter oral argument and his reply to Lior’s previous post on the Carpenter oral argument. 11/30 update: Lior’s replies to some of Matt’s questions and arguments are italicized and in brackets.]

Hi Lior – I was thrilled about the shout outs for our Empirical Fourth Amendment Scholars’ brief and my Northwestern University Law Review article during today’s oral arguments, at pages 17 and 48 of the transcript.  In fact, I blame my delay in posting on all the excitement this has generated.  I look forward to your piece on the effects of this decision on public expectations of privacy.

I too was struck by Justice Kennedy’s quip on page 26 that if he knows that cell phone companies collect location data, everyone else must too.  (It followed a more serious assertion that “almost everybody” knows that their cell phone companies store their location data.)  It’s not just that we have survey evidence that shows most people don’t know this.  But Justice Kennedy is in the economic and educational elite, a group that likely knows far more than the average Joe about technology and surveillance.  More to the point, he’s a judge hearing a case about the specific technology.  So of course he’s heard of it.  As I describe on page 172 of my paper about knowledge and the Fourth Amendment,  judges do a poor job of assessing societal knowledge, in part because they are humans and humans tend to automatically (and irrationally) impute their own knowledge to other people.  Assuming that it was meant to be taken seriously, this is a very clear example of that phenomenon.

Like you, I was intrigued by the question of property rights in third party cell phone records.  As sympathetic as I am to the idea that people have a strong interest in their cell phone records, one that is protected to some degree by statute, I confess I don’t see how to characterize this as a property right without distorting the concept of property.  Lior, did you have any thoughts on Carpenter’s attorney’s brief mention of trade secrets in his back-and-forth with Gorsuch? That struck me as a potentially interesting analogy. [Lior chiming in: I don’t see how the trade secrets analogy gets Carpenter any traction in this case. Trade secrets are private information that have commercial value to a firm, so when we’ve seen trade secrets analogies arise in Fourth Amendment cases it’s involved things like aerial surveillance of a chemical plant, as in Dow Chemical. Carpenter’s cell phone carrier has a trade secret interest in the data, but the interest is limited by the Stored Communications Act and the carrier isn’t asserting such a proprietary interest in this litigation. That does not mean that Carpenter loses under the positive law model. Will Baude argues here and Richard Re argues here that Carpenter should win under the positive law model. I just think if they win it’s going to be on something besides a trade secrets rationale. That said, Justice Gorsuch’s line of questioning suggests he might have something up his sleeve. Maybe him and his law clerks have combed through Michigan property law and come up with a really helpful precedent for the property rights perspective.]

Let me highlight a few other themes from the oral argument.  First was that none of the Justices seemed to care for the mosaic theory pushed by Carpenter’s counsel.  Even the Justices that appeared to favor Carpenter noted that it was tough to draw a conceptual line between 1 day of historical cell phone tracking and 100 days.  Maybe they shared the intuitions of the people surveyed in Lior and Matthew Kugler’s study on the mosaic theory. [Lior again: I don’t think that’s the explanation. In Jones five justices seemed to have intuitions that were very much in line with the mosaic theory, and with Judge Ginsburg’s eloquent articulation of it in the DC Circuit. But in the intervening years they might have come around to the view that making the mosaic theory into workable doctrine is very hard, as Orin Kerr and other scholars have suggested.] In this case at least, I think the Justices are correct to eschew the mosaic theory.  With historical location surveillance, the potential scope of surveillance, and the resulting chilling effects, extend for years.  So even if the police only track me for 1 day, I would be subject to tracking for my entire life, or at least as far back as records are kept.  Justice Roberts seemed sympathetic to this view in his remarks on page 12.

Second, the most successful argument made by the government and the Justices sympathetic to its position was that Smith and Miller are expansive precedents and the surveillance they allow is no worse than that of limitless location tracking.  I think the amicus brief filed by the Scholars of Criminal Procedure and Privacy did a great job of explaining the distinctions between those cases and Carpenter.  For instance, information technology and infrastructure has changed radically since the 1970s; those cases involved voluntary and knowing transmissions of information and Carpenter very likely does not; cell phones, unlike land lines, can be tracked even if the user takes no action, etc.  But even setting those distinctions aside, it would be perfectly appropriate for the Court to declare that the principles of Smith and Miller are obsolete and that their questionable holdings will be upheld simply as a matter of stare decisis.  Indeed, one aspect of Miller might be eliminated as simply untenable.  Justice Alito notes on page 5 that things like credit card receipts can reveal a great deal about a person’s movements and habits.  And he’s right.  The Court might consider limiting the scope of Miller to less revealing and less intimate bank records and account information – perhaps by signaling a willingness to do so in this case and then waiting for a defendant to challenge the warrantless collection of credit card records in a later case. [Lior: This is a very good point. One of the things I keep thinking about is the discussion in Riley of how the process of getting a warrant has changed. As the Chief Justice mentioned in Riley and McNeely, magistrate judges can authorize searches that arrive via email very quickly on an iPad. That wasn’t true in 1979. So maybe the Court sees the transaction costs of getting a warrant falling and the probable cause standard as appropriately protective of privacy interests. There probably was probable cause in Smith v. Maryland, and in Carpenter, for that matter. So maybe this will be another “get a warrant” kind of opinion that signals trouble for the 1970s era third party doctrine precedents in future cases.]

More broadly, Breyer seems to endorse the idea that more sensitive and personal data will be protected, while less sensitive data may not be, on pages 66-67.  In the end, I would guess that the Court distinguishes Miller and Smith along these lines.

Finally, I am reasonably confident that the Court will wind up favoring Carpenter.  Based on the transcript, I have a hard time seeing Sotomayor, Ginsburg, Breyer, or Kagan siding with the government here, and I think Gorsuch feels strongly that the government cannot obtain these records without violating citizens’ rights.  Chief Justice Roberts has shown himself in cases like Riley v. California to be attuned to the problems that new technologies pose to privacy.  More generally, I think the most important theme of the argument and the case is simply that the Court, and society in general, is uncomfortable with the enormous scope of the power that the government is claiming here.  Justice Kagan on page 69, Justice Gorsuch on page 73, and other Justices as well signal that they cannot endorse the concept that there is no constitutional limit on the government’s collection of even very sensitive information just because it rests in the databases of a third party. [Lior: Maybe. The fun part about this is that we don’t know what cards Justice Gorsuch is holding in his hand. The justices asked lots of hard questions to both advocates. And a majority opinion reversing the Sixth Circuit is going to be a challenging opinion to write, with a lot of heavy lifting, so conference votes could conceivably shift.]

That said, oral argument is no guarantee of how Justices will eventually vote.  I’ll be waiting excitedly to see how the case eventually comes out.




Quick Reactions to Today’s Carpenter Oral Argument – Post 1

Dear Readers,

As you may know, the Court heard oral argument in Carpenter v. United States this morning, and the transcript was posted this afternoon. Matt Tokson (Utah) and Lior Strahilevitz (Chicago) have been blogging about Carpenter all week, so what follows are there thoughts on the argument. Lior will post his thoughts here first, and then Matt will share his thoughts in a subsequent post. The transcript is available here, and the dialogue will provide page references to the transcript.


First off – kudos to Matt, whose ears must have been burning today! The Empirical Fourth Amendment Scholars’ amicus brief that he wrote with Matthew Kugler, Sarah Schrup, Christine Scott-Hayward, and me got a couple of mentions during the oral argument, at pages 17 and 48 of the transcript. Both Carpenter’s attorney, Nathan Wessler, and Justice Sotomayor brought up the brief and the scholarship summarized therein, particularly Matt’s terrific Northwestern Law Review article.  I’m glad the empirical article and brief seemed to be helpful to counsel and at least one justice. Regardless of what the Court decides in Carpenter, it will be fun to see how public expectations of privacy adjust to the decision in real time. That is something that I’ve written about with Matthew Kugler (Northwestern), in an article that the University of Chicago Law Review published this morning. And we’ll have more work like that in the future.

I’ll also take a moment to brag about my Chicago colleague Will Baude, whose Harvard Law Review article with James Stern (William & Mary) pretty clearly shaped Justice Gorsuch’s approach to the case.  If you want to make the point that empirical and theoretical legal scholarship can be helpful to the Supreme Court when it considers hard cases, this was a good day.

Second, I thought I’d highlight a few moments in the oral argument transcript that jumped out at me. I thought the best move a lawyer made in the case was Wessler’s response to questioning from Justices Alito and Ginsburg. Wessler was faced with what I regard as one of the government’s two best arguments – the idea that Congress should determine when reasonable expectations of privacy exist, and they’ve done that in the Stored Communications Act. (The government’s other strong argument is that the Court should just follow Smith and Miller, and view the third party doctrine as dispositive.) That’s an argument that Justice Alito seems partial to, based on his Jones concurrence. Wessler argued (at pg. 19) that we can view Congress as having given law enforcement options – get a warrant when it’s trying to collect particularly sensitive information and a 2703(d) order when it’s getting less sensitive information. Indeed, you can push Wessler’s argument further and say that the government’s reading of the Stored Communications Act arguably renders the section 2703(c)(1)(A) warrant requirement superfluous. Because, after all, why would the government ever seek a warrant when it can just get a 2703(d) order much more easily? Wessler’s argument didn’t occur to me previously, but it really blunts the government’s point, though I’m not at all sure it convinced Justice Alito. That’s excellent lawyering on Wessler’s part, though, a real high point in a fine argument.

Third, I am not sure how to read the laughter after Justice Kennedy’s statement on page 26 that if he knows his cell phone is being tracked via cell tower geolocation and those records are being stored, then most people must know it too. I mean, if he was being sarcastic, then great. Of course an experienced Supreme Court justice who has been an appellate jurist for decades, is extremely well-educated, relatively affluent, etc. is going to know more than the average person, even when it comes to cell phone technology. Only a third of Americans can name even a single branch of government! So I guess I really want to know whether Justice Kennedy was being self-effacing or whether he was being serious. If the latter, then I really wish he would sit down to digest the data Matt collected, which shows how little most people understand about what data their phones collect and the phone companies store. Lawyers have to always keep in mind how unrepresentative our own social networks are of the nation as a whole. Combating that problem is why we collect this data.

Fourth, the Court was struggling a little bit with the question of property rights in stored cell site records. Pg. 55. I’m not sure the ball was advanced very far. As a scholar of both property law and privacy law, I found the discussion intriguing though. I do think there are examples of situations in which a third party might have property rights in information, but the information concerns me so I have some residual property interest in it as well. This was a point that Wessler made in rebuttal. The first example that springs to mind is a photograph of me that a journalist takes without my consent. It is surely the case that if someone breaks into the journalist’s office and steals the photo, then uses the image of me for commercial purposes without my permission, they’ve violated my right of publicity. And that’s true even though I didn’t create the image or even know of its existence. So there are definitely instances where property law (or IP law) explicitly does something like what Justice Gorsuch was suggesting. But I am not sure there is a conversion case that gets us all the way there, so probably the positive law approach requires reasoning from first principles rather than relying on clear common law precedents. (Hobby horse Property professor moment: I was gratified when Justice Alito described the right to destroy property (pg. 56) as a hallmark test for whether someone owns something.)

Fifth, Justice Sotomayor made an interesting argument in distinguishing Miller from Carpenter on the basis that human beings handle deposited checks and other banking information but all the data collected to create historic cell site information was fully automated, so a human being never saw it. I can think of at least one smart scholar who agrees with her.

A final thought. People in the room who have great instincts, like Orin Kerr and Paul Ohm, both seemed to think that Carpenter will prevail based on their tweets. From the transcript I’m less sure about that. But this is an instance where I think that there’s probably a lot of information to be gleaned from body language and tone of voice that doesn’t come through in the transcript.

Matt, what jumped out to you? And what did our readers think?

[See this post for Matt Tokson’s responses.]





The Fourth Amendment Does Not Require “Demonstrative Action” to Protect Privacy

In a previous post, we discussed the test that the Supreme Court will likely use to resolve United States v. Carpenter, the major Fourth Amendment case that will be argued in the Supreme Court tomorrow. We responded to Orin Kerr’s argument that the Supreme Court should not consider people’s actual expectations of privacy in resolving Carpenter. In this post, we will examine Orin’s proposed alternative test and discuss the state of public knowledge about cell phone location tracking.

In Orin’s recent blog post, he discusses the connection between people’s knowledge of cell phone technology and their expectations of privacy in their cell phone’s location. Each of the appeals courts to examine the constitutionality of historical cell phone location tracking has based its decision in part on the extent of societal knowledge about cell phone technology. Controversially, most of these courts, including the Sixth Circuit in Carpenter, have concluded that cell phone users are generally aware that their cell phone companies are tracking their locations and storing records of their movements. This is a somewhat remarkable claim regarding public knowledge of an obscure and complex location tracking technology—and empirical surveys of cell phone users suggest that it is mistaken.

One of us has recently conducted a large-scale survey indicating that Americans are overwhelmingly not aware that their cell phone providers collect location information on them via their cell phones. Indeed, most people do not seem to be aware that their movements can be tracked using their cell phone signals. Accordingly, they do not knowingly disclose information about their movements to third parties.  Nor do they consent to such disclosure, because one cannot consent to something unconsciously or unknowingly.

To his credit, Orin acknowledges the possibility that cell phone users are unaware of cell phone location tracking. He instead argues that users may eventually acquire this knowledge, in which case a decision in Carpenter’s favor on the basis of societal knowledge would eventually become “wrong.”

We have several responses to this.  One is that a decision premised on an accurate assessment of societal knowledge at the time when Carpenter was tracked would not become “wrong” just because people eventually gain advanced knowledge of cell phone technology. Regardless of some hypothetical future defendant’s knowledge, it is fairly clear that Carpenter did not knowingly disclose his movements to a third party, and therefore did not forfeit his Fourth Amendment protections. Carpenter’s contemporaries (i.e., present-day Americans) generally shared his expectations.

Moreover, a large increase in knowledge of cell phone technology is unlikely in the foreseeable future. Public ignorance of even basic science is widespread and persistent. And, as we discussed in our previous post, social science studies indicate that Supreme Court cases have little impact on the perceptions or knowledge of the general public.

In any event, we consider Orin’s proposed alternative test for the Fourth Amendment’s scope to be untenable. Orin argues in Part IV of his amicus brief that the Court should ignore actual expectations of privacy and instead look to whether a citizen has “exhibited” an expectation of privacy by taking affirmative steps to prevent observation. Thus Orin contends that an expectation of privacy must be “demonstrated by an act” in order to receive constitutional protection.

Although Katz himself acted to protect his privacy by closing the telephone booth door before placing a call, a “demonstrative action” test would be a major departure from existing Fourth Amendment law, and an unwelcome one.

Fourth Amendment law is full of examples of courts finding Fourth Amendment protection for information accessible to others, even when the target has taken no demonstrative action to protect it.  Kyllo engaged in no demonstrative action to prevent heat from escaping his house.  Bond engaged in no demonstrative action to prevent the touching of his luggage. Five Justices agreed that tracking Jones’s location via GPS violated the Katz test, although Jones took no affirmative step to prevent the observation of his movements. Most people take no demonstrative action to prevent observation of their emails or the web sites they visit.  Like Carpenter, the people in these examples reasonably expect privacy in their information and belongings. In fact, people who reasonably expect privacy in a given situation may be less likely to take action to protect their privacy, because such action is likely unnecessary. Requiring citizens to take affirmative steps to prevent observation of their information in order to claim Fourth Amendment protection would drastically depart from existing law and substantially shrink the scope of the Fourth Amendment.


Should Fourth Amendment Law Pay Attention to What People Expect? If So, How?

In our previous post we responded to Orin Kerr’s argument that an originalist should vote to affirm the Sixth Circuit in Carpenter v. United States, the blockbuster case that will be argued in the Supreme Court on Wednesday. In this post we will say why we think his attack on the probabilistic model is misguided. Because all the published social science research suggests that average Americans regard warrantless access to historic cell site records as unexpected, the probabilistic model strongly suggests that Carpenter should win his case. As a matter of full disclosure, we were two of the principal drafters of the Empirical Fourth Amendment Scholars’ amicus brief that was filed in Carpenter.  Orin’s brief takes issue with that brief’s approach beginning at page 25 of his amicus brief and in this blog post. In the paragraphs that follow we will explain why we think his criticisms are not persuasive.

It is important to begin with a tip of the cap to Orin for his terrific and influential article, Four Models of Fourth Amendment Protection, which articulated a very persuasive descriptive claim, which is that in its approach to cases involving the question of whether police conduct is a search, the Supreme Court has not applied a consistent methodology. Sometimes, Orin notes, the Court applies a probabilistic model, which asks, if the police hadn’t conducted the surveillance at issue, how likely it is that a bystander would have learned the private information that the defendant is trying to exclude. Sometimes, he notes, the Court asks whether what the government did to gather the information at issue would have violated the target’s legal rights, arising out of property law or perhaps privacy tort law. This is the positive law model. Sometimes, the Court focuses on how sensitive the information sought and obtained was. This is the private facts model. And sometimes, the Court engages in a cost-benefit analysis of the government’s surveillance. Orin calls this the policy model. In many instances, Orin notes, the Court engages in more than one methodology at once. And the Court has at various times approached “search” cases in inconsistent ways, embracing methodologies that were attacked in earlier cases and attacking methods that were embraced in subsequent cases. To many readers of Orin’s seminal article, Fourth Amendment law sounds like a mess.

This messiness has prompted some scholars to argue that the Supreme Court could make Fourth Amendment law more coherent and much more predictable by just sticking with one model. For example, Will Baude and James Stern have argued on both originalist and pragmatic grounds that the Court should just stick with the positive law model in Fourth Amendment search cases. See also Will’s recent blog post. Chris Slobogin has argued that something like the probabilistic model should predominate, though aspects of the policy model also work their way into Slobogin’s balancing framework.  And various other scholars, including one of us, have also embraced a Fourth Amendment jurisprudence where the probabilistic model looms large.

Orin draws very different implications from his paper. Whereas other scholars see maddeningly inconsistent and unpredictable Fourth Amendment law, Orin thinks four models are better than one, arguing that it is optimal for the Supreme Court to mix-and-match different models to different circumstances. Orin argues that there are patterns that help explain why the Court usually favors one model or another, but the Court seems unaware of these patterns and does not inevitably adhere to them. This was true when Orin published his article a decade ago, and it remains true today, even though Orin’s article has already been cited nine times by state and federal courts. We think it’s fair to say that while Orin’s descriptive claim (there are four models) has convinced many Fourth Amendment scholars, his normative claim (there ought to be four models) has won fewer converts.

We think one reason why is straightforward. If everyone agrees that there is one model to determine whether surveillance constitutes a Fourth Amendment search then the fight is limited to what results are dictated by that model. By contrast, if there is a fight over both which model applies and what outcome results from the application of the model, then Fourth Amendment results will be quite unpredictable. This makes it harder for police officers to figure out ex ante what they can do without a warrant and increases the temptation for judges to reach results that are consistent with their ideological priors.

Another reason why we aren’t persuaded by Orin’s normative argument is that hard Fourth Amendment cases often involve areas of overlap between two different models. For example, Orin argues that “the private facts model appears particularly often in cases involving new technologies” (pg. 543) and that “the positive law model tends to govern physical access to houses, packages, letters, and automobiles” (pg. 544). So what is the Court to do in a case like Jones, which involved new technology used to track an automobile? Orin’s framework doesn’t provide a correct answer, and the opinions in that case articulated a mix of private facts arguments, probabilistic arguments, and positive law arguments, which were decisive to the majority.  Or consider various cases involving shared access to a home or car. Are those cases where the positive law model should apply, or the probabilistic model, which Kerr says “mostly surface in investigations that occur in group settings.” (pg. 544)? The Court gets to choose, and its choice will determine the outcome. A choice of four models and no clear rule about which applies makes Fourth Amendment precedent a less meaningful constraint on judges.

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Carpenter v. United States and the Role of Originalism

Orin Kerr is undeniably one of the country’s leading authorities on the Fourth Amendment, particularly its applications to computers and other electronic devices. We have learned a great deal from his scholarship and blogging on these issues, and we admire both the clarity of his writing and the deep reservoir of legal knowledge he brings to these subjects. But we humbly submit that in his blogging and briefing of Carpenter v. United States, a blockbuster Fourth Amendment case that will be argued on Wednesday, he’s missed the mark. In a series of blog posts, we’ll give our own account of the issues presented in Carpenter.

Carpenter concerns the ability of the government to obtain a cell phone subscriber’s historic cell site information without a warrant. As people carry cell phones around with them and use them to make calls, signals from those phones are pinging off the nearest cell phone towers, and their proximity to various towers at differing times of day permits the police to reconstruct the cell phone user’s whereabouts in physical space. Cell phone carriers retain this historic cell site location, evidently for periods ranging between a year and seven years, depending on the carrier. The Sixth Circuit held that no warrant is required for the government to obtain this information from a cell phone provider, and the Supreme Court granted cert.

In a blog post about Carpenter, Orin argues that originalists should probably support the respondents in Carpenter. We have a few points to add to the excellent amicus brief by several legal scholars evaluating the Fourth Amendment’s original meaning.

First, if the question is whether the Founding Fathers would have countenanced law enforcement’s warrantless tracking of an individual’s location for weeks at a time, we suspect the answer is probably not. Or they might have thought that if the government wanted to do that, it would have needed to expend very substantial resources each time, by arranging for round-the-clock tails whenever a surveillance left home. What troubles many about the use of historic cell site records is that it has become very cheap and easy for the government to gather information about many peoples’ whereabouts over a long period of time without them even knowing about it. That gives the government an awful lot of power in a way that exposes a lot of sensitive personal information without a strong government justification for collecting it. One function of the Fourth Amendment is to raise the costs of certain kinds of government searches, precisely so that the government will only elect to expend those resources when they really need the sensitive information at issue. This is a point that Justice Alito’s concurring opinion in Jones makes forcefully, at the beginning of Part V.  (See also this terrific paper by Minzner and Anderson.)  The precise issue of geolocation surveillance didn’t come up during Founding era debates in part because the kind of massive surveillance the government is now engaged in would have been unimaginable, especially in a country without professional police forces and a much smaller government than we have today.

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