What's At Stake in Today's Geofence Oral Argument?
Later today, the Supreme Court will hear oral argument in Chatrie v. United States. The case presents the question "whether the execution of the geofence warrant violated the Fourth Amendment." Wait. The execution of the warrant? The warrant? And what's a geofence?
The case is on cert from a Fourth Circuit en banc decision that my co-blogger Professor Matthew Tokson discussed and critiqued in July 2024. Here is how he introduced the case:
On May 20, 2019, a man wearing a fisherman’s hat and a traffic vest robbed a bank in Midlothian, Virginia. Unable to identify the robber, police served Google with a geofence warrant—a warrant targeting all cellphone users in a certain area at a certain time. They obtained information on several cellphones in the area of the bank at the time of the robbery, including the phone of Okello Chatrie, who was eventually identified as the culprit. Chatrie challenged the validity of the geofence warrant, arguing that it was unconstitutionally overbroad.
Chatrie lost in the Fourth Circuit. His cert petition presented two questions, but the Supreme Court granted review on only the first one, quoted above. Although petitioner's counsel wrote that question, it doesn't fully reflect the argument petitioner's merits brief makes. The brief argues first that the geofence warrant itself, and not merely its execution, was invalid because it was effectively the equivalent of a general warrant, given the number of mobile phone users it swept up. It is widely accepted that general warrants--those that did not target particular individuals for particular reasons--were a chief abuse that motivated the adoption of the Fourth Amendment in the first place.
In addition to arguing that the original geofence warrant was invalid, petitioner makes a number of other arguments about its execution. Even if the original warrant was valid, petitioner argues, the subsequent steps after the initial dragnet that allowed law enforcement eventually to zero in on him were themselves searches for which a warrant was required but not sought or obtained.
Before getting to any of that, however, petitioner addresses an argument made by the Fourth Circuit that no warrants were necessary at all because of the third-party doctrine. The core idea is that if you voluntarily disclose information to a private ("third") party, and that third party decides to hand the information over to the government, you have not been subject to government surveillance. If that strikes you as not merely a giant opening for the government to invade privacy but also wrong as a factual matter, you're not alone. Professor Sherry Colb raised that objection in numerous places, including this 2002 Stanford Law Review article. The petitioner argues that the third-party doctrine shouldn't apply to cell phone location data, citing, among other things, the Supreme Court's expression of concern about the scope of privacy at issue in Carpenter v. United States.
The petitioner's merits brief also argues that petitioner, not Google, owns the location data. That may seem like a strange point, but it is motivated by a turn in some recent cases towards reconceptualizing the Fourth Amendment as a protection for property, not privacy. Professor Colb also critiqued that move in various writings, including this 2004 article in the Michigan law review. That article was framed in substantial part as a response to positions that Professor Orin Kerr took in his scholarship. (Professor Kerr has filed an amicus brief on his own behalf in support of the government in Chatrie.) In addition to taking issue with the proper role of property in our understanding of the Fourth Amendment, Professor Colb also disagreed with Professor Kerr's suggestion that Congress, rather than the courts, should fashion protection against threats to privacy from new and fast-changing technology. Her position was not that Congress shouldn't do so but that the courts were needed nonetheless. The ensuing years of inaction by Congress strike me as vindicating her view.
The good news regarding Chatrie for privacy proponents is that the particular outcome of the case might not matter much. As Amy Howe notes in her SCOTUSblog preview, "Google now stores location data on mobile devices themselves, rather than in its own database." Thus, geofence warrants to Google will no longer yield a dragnet.
However, other companies are not necessarily so solicitous of privacy. When Google was collecting location data, it was doing so from all devices running Google apps. Thus, even if you didn't have an Android device, running Google for search, using Google Maps, or having Gmail on your phone meant that you were sharing your location data with Google. As Professor Tokson's 2024 essay explained, it was nearly impossible to opt out. It's progress that Google no longer collects such data, but other apps could be collecting it and sharing location data with the government, and even if not, some location data can be derived from mobile providers like Verizon and AT&T.
Chatrie holds potentially broader implications as well. The government's brief repeatedly states that the geofence and other data provided information only about the petitioner's "public movements." Among its other arguments, the government contends that a person who is out in public has no reasonable expectation of privacy in their location information because other members of the public can plainly see where they are. There is some reason to hope that the Court will reject this argument, which it already rejected in Carpenter. That case distinguished more primitive tracking methods of the sort upheld in United States v. Knox.
But there is also reason for concern. Chief Justice Roberts was the only one of the Court's current conservatives who was in the majority in Carpenter. Unless at least one of Justices Kavanaugh and Barrett (neither of whom was on the Court when Carpenter was decided) join with him in seeking to protect privacy in the digital age, the Court could decide Chatrie in a way that gives the green light for practices and technologies that ensure effectively constant surveillance of everyone. The Palantir-provided apps that ICE agents use to instantly identify and issue veiled or not-so-veiled threats against anyone who protests their activities speak to the scope of the threat.
That is not to deny that new technologies can enable federal, state, and local law enforcement to quickly identify and apprehend dangerous actors. Ideally, Congress would craft legislation that carefully balances the law enforcement gains against the privacy and other losses from each new technology. In reality, if the Supreme Court does not do so, no one will, and the result will be a surveillance state.
-- Michael C. Dorf