The Cyberlaw Podcast is back from hiatus – briefly! I've used the hiatus well, skiing the Canadian Ski Marathon, trekking through Patagonia, and having a heart valve repaired (all good now!). So when I saw (and disagreed with ) Orin Kerr's new book, I figured it was time for episode 502 of the Cyberlaw Podcast. Orin and I spend the episode digging into his book, The Digital Fourth Amendment: Privacy and Policing in Our Online World.

The book is part theory, part casebook, part policy roadmap—and somehow still manages to be readable, even for non-lawyers. Orin's goal? To make sense of how the Fourth Amendment should apply in a world of smartphones, cloud storage, government-preserved Facebook accounts, and surveillance everywhere.

The core notion of the book is "equilibrium adjustment"—the idea that courts have always tweaked Fourth Amendment rules to preserve a balance between law enforcement power and personal privacy, even as technology shifts the terrain. From Prohibition-era wiretaps to the modern smartphone, that balancing act has never stopped. Orin walks us through how this theory applies to search warrants for digital devices, plain view exceptions in the age of limitless data, and the surprisingly murky question of whether copying your files counts as a seizure. It's very persuasive, I say, if you ignore Congress's contribution to equilibrium. In some cases, the courts are simply discovering principles in the Fourth Amendment that Congress put in statute decades earlier. Worse, courts (and Orin) have too often privileged their idea of equilibrium over the equilibrium chosen by Congress, ignoring or implicitly declaring unconstitutional compromises between privacy and law enforcement that are every bit as defensible as the courts'.

One example is preservation orders—those quiet government requests that tell internet providers to make a copy of your account just in case. Orin argues that's a Fourth Amendment search and needs a warrant, even if no one looks at the data yet. But preservation orders without a warrant are authorized by Congress; ignoring Congress's work should require more than a vague notion of equilibrium rebalancing, or so I argue. Orin is unpersuaded.

We also revisit Carpenter v. United States, the 2018 Supreme Court decision on location tracking, and talk about what it does—and doesn't—mean for the third-party doctrine. Orin's take is refreshingly narrow: Carpenter didn't blow up the doctrine, but it did acknowledge that some records, even held by third parties, are just too revealing to ignore. I argue that Carpenter is the judiciary's Vietnam war – it has committed troops to an unwinnable effort to replace the third party rule with a doomed series of touchy-feely ad hoc rulings. That said, Orin's version of the decision, which deserves to be called the Kerr-penter doctrine, is more limited and more defensible than most of the legal (and judicial) interpretations over the last several years.

Finally, we talk border searches, network surveillance, and whether the Supreme Court has any idea where to go next. (Spoiler: probably not.)