Nathan Wessler Nathan Wessler, staff attorney with the ACLU. Carpenter v. United States marks a significant gain for privacy advocates on behalf of Timothy Carpenter before the court Legaltech News: What questions remain unanswered in this decision? And second is what this opinion says about the status of the third-party doctrine in the digital age. The Carpenter decision holds that the police need a warrant to get someone's historical cellphone location data. But in doing so, the court has created space for future cases to address what protections are necessary for all the other kinds of highly sensitive digital age data that's held by third-party companies. That's everything from the content of our emails to information generated by GPS on our phones, whether it's medical information or a record of everything we read on newspaper apps or fertility tracking data or so much more. Information about the state of our bodies being collected by a smartwatch or another wearable medical device, information about the interior of our home from internet of things devices, like a smart thermostat that knows when you're home and maybe what room you're in. The Carpenter decision doesn't directly answer the question of when a warrant is going to be required for which of those other kinds of data, but it is the first time in four decades the Supreme Court has revisited the third-party doctrine, and the court did so in a way that creates real momentum toward protecting a wider array of highly sensitive digital age data going forward, and that is extraordinarily important. What does this mean for the average American in terms of their privacy rights? So I do think [the Carpenter ] decision is going to make a difference there, because it puts those companies on much firmer ground to have policies that say, “We have all the sensitive data. We can turn it over to law enforcement when necessary, but we will only do it pursuant to a search warrant based on probable cause.” What does it say about each justice's view on the Fourth Amendment and their respective relationships with technology? The majority opinion is the latest in a series of opinions that strongly recognizes that the Fourth Amendment has to be interpreted in ways that keep up with developments in technology. So the chief justice's opinion in this case looks a little bit like his opinion in Riley [ v. California ] , the case about searching the content of cellphones from a couple of years ago. In both decisions, the court and Justice [John] Roberts had recognized we can't just rotely extend pre-digital judicial precedents to digital age surveillance and search techniques. The language on that theme in the Carpenter decision just couldn't be stronger. And I think in Justice [Samuel] Alito's dissent, we can see some real anxiety and disagreement about how to make those changes without throwing out entire sets of Fourth Amendment doctrine. He would stick with the old rules and is apparently willing to accept the consequences for privacy. Justice [Neil] Gorsuch's opinion is really interesting, too—it's styled as a dissent, but really it's a dissent in name only. He goes into great depth into his view of why the government investing in techniques raises concerns and how he thinks we could appropriately address those, not through privacy principles but through more of a property-based approach. He doesn't totally flesh out how that will look in future cases, but he provides a lot of guidance going forward that I think we will see a great number of legal challenges from defense attorneys and others that include sections that take Justice Gorsuch up on his invitation to raise that theory as well. Hopefully we will find some clarity in the future from the lower courts as they start to address that question. What do you find the most significant about the ruling? Is there anything you wish would have gone differently?

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