Applying the Fourth Amendment to the Internet, Part I -- Technology Neutrality: (This is the first of a short series of posts on my new forthcoming article, Applying the Fourth Amendment to the Internet: A General Approach).

  For the last several years, I've been pondering how the Fourth Amendment should be applied to the Internet. The question is difficult in part because to start off you need some sort of a theory as to what the Fourth Amendment means. It's not enough to just follow the terms of existing doctrine, as the doctrine itself is largely indeterminate: What is a "reasonable expectation of privacy," after all? And what makes a search "reasonable"? That doesn't take you very far without some sort of theory about what the Fourth Amendment does.

  Nor does high-level constitutional theory answer very much here. For example, say you're an originalist. It's kind of hard if not impossible to know how that pans out. First, the original public meaning of terms like "unreasonable searches and seizures" remains hotly contested. Second, not only were there no professional police officers at the framing, there was of course no Internet. And if you're a serious originalist, you probably have to rethink the incorporation doctrine, too, which means that you may not even be regulating most police officers any more. So that doesn't necessarily take you very far, either.

  So what to do? In my new paper, I start with an assumption I call "technology neutrality." The idea here is that the Fourth Amendment should apply to the Internet much like the Fourth Amendment applies to the physical world. I therefore start with the role that the Fourth Amendment plays in regulating traditional physical investigations, and I look for ways that the Fourth Amendment should be applied to try to replicate that role online given the very different facts of the Internet. Thus, the goal is "technology neutrality": Ideally, The Fourth Amendment should play the same role regardless of whether a criminal investigation occurs via an investigation in the physical world or whether it occurs via an investigation over the Internet.

  Incidentally, for those well-versed in Larry Lessig's work, my approach ends up being something akin to Lessig's idea of constitutional "translation," although at a more specific level. Whereas Lessig sees the Fourth Amendment as a general protector of privacy, and so envisions the Fourth Amendment as sort of a roaming tool for protecting privacy online, my idea is to look more specifically at how the Fourth Amendment does and does not protect privacy and to recreate both sides of that picture in the new space.

  But why assume "technology neutrality"? To be clear, technology neutrality is just an assumption in my article: I don't actually argue for that position from first principles. If you have theoretical commitments that rule out technology neutrality, then you're just not going to get much out of the paper: It's not the paper for you.

  At the same time, I think the assumption is a helpful one to make for a good practical reason: It's what judges and Justices today think the Fourth Amendment requires. That is, the assumption of technology neutrality captures the general understanding among judges and Justices about how the Fourth Amendment is supposed to be interpreted. This understanding follows a trio of cases in 1967: Berger v. New York, Katz v. United States, and Warden v. Hayden. In all three cases, the Supreme Court had to choose at a conceptual level between the Fourth Amendment as a specific set of protections grounded in history and the Fourth Amendment as a general tool to make that make sure the police don't have too much power. In all three cases, the general view won out.

  Today, every Supreme Court Justice (and every judge I can think of) adopts that basic view. The 1967 view has stuck. The Fourth Amendment is now understood as a tool for requiring "reasonable" police practices in the sense of sensible or desirable ones. Different judges have a different sense of what that means, of course, but pretty much everyone agrees that this is the goal. And implicit in that goal is technology neutrality: If the Fourth Amendment is a general tool for requiring reasonable police practices, then presumably it should require reasonableness in equal degrees regardless of whether the case happens to involve a physical investigation or an Internet investigation.

  So for all practical purposes, we live in a world in which the legal culture and shared understandings of what the Fourth Amendment does require some kind of technology neutrality. You might like it; you might not. But it's the world we're in. What does that actually mean for the Fourth Amendment as applied to the Internet? Stay tuned for that my next post.

Applying the Fourth Amendment to the Internet, Part II -- Replacing the Inside/Outside Distinction with the Content/Non-Content Distinction: (This is the second of a short series of posts on my new forthcoming article, Applying the Fourth Amendment to the Internet: A General Approach, forthcoming in the Stanford Law Review. For the first post, click here.)

  So imagine you're trying to apply the Fourth Amendment to the Internet so that it plays the same role in Internet crime investigations that the Fourth Amendment plays in traditional physical investigations. How can you do that?

  The first step is to realize that the Fourth Amendment in the physical world is based on a fundamental distinction between inside surveillance and outside surveillance. If something occurs outside, the police are free to watch it: The Fourth Amendment doesn't regulate them. On the other hand, if something occurs inside, the Fourth Amendment presumptively applies: Barring special circumstances such as consent, the Fourth Amendment regulates government access to that inside space.

  The line between inside and outside can get a little tricky, to be sure. In fact, many of the most interesting cases consider exactly where the line falls (think Kyllo or the open fields/curtilage cases). But that distinction is essential to the Fourth Amendment in the physical world. It creates a zone that the police can monitor, mostly involving transactional information about where people are and what they are doing, while carving out a private zone where the police can't go without special circumstances, mostly involving the substance our of private thoughts, writings, and expression.

  Now turn to the Internet. Online, the distinction between "inside" and "outside" no longer makes a lot of sense. Some new distinction is needed to replace the function of the outside/inside distinction.

  My article proposes that the online distinction between content and non-content information should replace the physical distinction between inside and outside surveillance. The contents of communications, such as e-mail messages, subject lines, and remotely stored files, should be presumptively protected by the Fourth Amendment. Absent special circumstances such as consent or posting documents on the Internet, the Fourth Amendment should regulate government access to contents. On the other hand, non-content information, such as IP addresses mail header information other than the subject line, should not be protected.

  I think this approach nicely translates the Fourth Amendment to the Internet because content and non-content information are network substitutes for inside and outside. To see this, you need to think about how networks work and what functions they serve. Networks are means for transporting information or property from one place to another. Instead of transporting information or property yourself, you sit back and the network does that work for you remotely. The non-content information is the information in the network that is generated and used to deliver the package: It records where the package went, when, how big it was, and the like. In contrast, the content information is the package itself: It is the actual information that the person sent.

  Replacing the inside/outside distinction with the content/non-content distinction leads to a technology-neutral Fourth Amendment because the latter is a network substitute for the former. The non-content information — that information generated to deliver the package — is the network substitute for what would have been open to public observation and therefore "outside" in a physical environment with no network. The content information is the network substitute for what would have been hidden from public observation and therefore "inside" in a physical environment.

  Replacing inside/outside with content/non-content maintains the same basic function of the legal distinction in light of the shift from physical space to network space.