Christopher Slobogin's previous book about the Fourth Amendment focused on then-cutting-edge technologies of police surveillance: thermal imaging devices, digital dossiers, and drones. Fifteen years later, we live in a world of facial recognition technology, dragnet geolocation tools, and predictive algorithms. The time is ripe for a sequel.
That sequel comes in the form of Virtual Searches, which offers a taxonomy of different types of modern police searches, asks policymakers and judges to think differently about each type of search, and calls on legislative bodies—not just courts—at all levels of government to craft nuanced rules that balance the right to privacy against law enforcement needs. In so doing, Virtual Searches lays claim to what Slobogin calls a middle ground between abolition and “law and order,” between bans on technology and police discretion, and between the world some of us might want and the politically constrained world we live in today.
Virtual Searches is a serious, accessible, and illuminating journey through the surveillance practices of modern police departments and Slobogin's thoughts on how the law should respond. It makes several contributions to the sociolegal literature on state searches and seizures. The primary contribution is descriptive. Slobogin neatly and persuasively categorizes police searches that use advanced technologies to collect information on individuals into five categories, including, among others, those aimed at predicting behavior based on profiles or latent characteristics and those that use geolocation tools to identify people at a particular location at a particular time. The key for Slobogin is that some of these searches are more invasive than others. Armed with this typology, Slobogin makes two additional contributions, both prescriptive. He first suggests that the justifications for each type of search should be proportionate to the search's invasiveness. Then he argues that legislatures at all levels should determine the proper balance. Local city councils should take the lead on regulating virtual searches that have mostly localized effects, whereas state and federal legislatures should step in to address more systematic surveillance practices.
I learned a lot from Virtual Searches. It also raised some questions, two of which—the book's reliance on legislatures and its categorical approach to data—I will frame as provocations as Slobogin continues the Virtual Searches research agenda.
Slobogin puts a lot of faith in the legislative process. When the book begins, the Nashville City Council is deciding between a proposal to limit the use of automated license plate readers, or ALPRs, and a police-backed proposal expand their use (1). When the book ends, a Minnesota police officer has just been convicted of murdering George Floyd (209) and Nashville was again debating new proposals on ALPRs. There was, again, a narrow proposal that would limit ALPRs and a broad one that would give police expansive powers. A debate ensued, the public made comments, and the expansive proposal won (210). This, to Slobogin is a “fitting outcome for the kind of difficult issue that should be resolved only through democratic debate” (210).
I do not find that outcome to be fitting at all. I find it lamentable and rather predictable. I am less sanguine than Slobogin about the prospect of all but a few local legislative bodies being capable of doing anything other than adopting their version of the broad proposal. At the local and state levels, police unions are too strong, “law and order” rhetoric is too manipulative, the media is too complicit, and politicians are too opportunistic. What is more, the vast majority of people do not participate in local politics. Not that courts are likely to be any better. There is no easy answer to this problem, but I encourage Slobogin to think more critically about the sociopolitical and sociolegal contexts in which his recommendations would operate and what it means to rely on a democratic process that is increasingly not democratic at all.
A second consideration for future research focuses on Slobogin's occasional adoption of a categorical public/private distinction when it comes to the data collected and used by algorithmic systems. For example, New York's Domain Awareness System (DAS) “aggregates and analyzes existing public safety data streams” from almost any source you can think of—cameras, license plates, cell phones, radiation detectors, 911 calls, social media scanners, and more (96). Slobogin suggests that if the data collected and used by DAS is “‘public’ or generated by police observation of public activity,” police would not need probable cause to justify deploying DAS (97).
The word “public” is doing a lot of work here, but it is not clear what it means. Does it follow the third-party doctrine, a secrecy paradigm of sorts? Something else? What is the difference between “public” data and “observation of public activity”? Plus, relying on an undefined public/private distinction to determine probable cause runs headfirst into the realities of the very technological developments that gave rise to Virtual Searches in the first place. Machine learning tools can take readily available data that Slobogin would consider “public” and nevertheless derive personal information covertly. If Slobogin seeks to imagine a different jurisprudence for Fourth Amendment searches, he might similarly consider re-imagining the traditional assumptions upon which that jurisprudence has been based.
In the end, Virtual Searches is informative, timely, and accessible. It will be valuable to all law students and undergraduates and to sociolegal scholars working at the intersection of law, technology, and society. It will spark discussion and heated debate while all sides learn from each other.
