Thanks to Matt Tokson for posting his thoughtful and smart reactions to the Carpenter case. I offered some less thoughtful and less smart thoughts about Carpenter earlier on Friday. After reflecting on the case over the weekend, I thought I’d offer a little bit more analysis of how the Court got here and where things are going from here.

1. The Forgotten but Major Role of Douglas Ginsburg and the DC Circuit. Casebooks generally focus on Supreme Court cases rather than lower court opinions in cases where the Supreme Court ultimately weighed in, and that’s understandable. But the intellectual heavy lifting in the case that would ultimately become known as Jones was done by the lower courts, and in particular by Judge Ginsburg’s masterful and at-the-time radical 2010 opinion in United States v. Maynard. (The case’s name changed by the time it made it to SCOTUS, but it’s the same dispute.) Here’s a post from Orin Kerr in the immediate aftermath of  the Maynard decision, which he described as “potentially revolutionary” but unpersuasive. To be sure, not everything that Judge Ginsburg wrote in Maynard eight years ago has come to pass, and the Carpenter Court is conspicuously less enthusiastic about the mosaic theory than the Jones concurrences were. But the idea that a comprehensive record of someone’s movements over time is deeply sensitive information got its most articulate defense by the DC Circuit, the DC Circuit opinion focused on the reasonable expectations of privacy analysis that was echoed in Carpenter rather than the narrower property theory that the Court ultimately adopted in Jones, and the fact that the opinion was the product of three of the country’s most widely respected appellate jurists (Ginsburg, Tatel, and Griffith) must have gotten the attention of Chief Justice Roberts, who served on the circuit court alongside all three (albeit briefly in the case of Judge Griffith.) With the benefit of hindsight I think we can now conclude that Maynard turned out to be “revolutionary” rather than “potentially revolutionary.” Maybe the Supreme Court would have eventually gotten to the same result in Carpenter anyway, but it’s entirely possible that the recent history would have played out very differently. And in remembering the role of the DC Circuit we should also note the contributions of Maynard’s court-appointed counsel (Sicilia Englert and Stephen Leckar) as well as the amici (the ACLU and EFF) in shaping the DC Circuit’s thinking. Maynard is worth a read or re-read for those seeking to understand how we got to Carpenter. 6/27 Update: Upon further reflection it’s worth noting that Judge Ginsburg’s opinion also anticipates the positive law model moves that Justice Gorsuch would later make in Carpenter, using several privacy tort law precedents (such as Nader and Galella) to develop the case for the idea that the Fourth Amendment protects geolocation privacy.