Yesterday Paul Rosenzweig pointed out an interesting law review article regarding the Fourth Amendment in the context of a nuclear terrorism scenario. The Fourth Amendment protects us against "unreasonable" searches and courts have ruled that the police do not have to establish probable cause or get a warrant in order to perform a search if that search occurs in a narrow set of circumstances that are thought to be "presumptively reasonable." In fact, in most national security contexts, warrantless searches are thought by the courts to be presumptively reasonable as far as the Fourth Amendment is concerned, and its not much of a stretch to imagine that they'd be allowed in a "Jack Bauer" scenario where the hunt is on for a nuclear terrorist.

What struck me as troubling about this article wasn't its main argument, but rather, a footnote. The article concludes that in a scenario where there is a high probability of a serious attack, the Fourth Amendment might allow for searches without probable cause. However, it struggles with how to handle the scenario where there is a risk of a serious attack, but there is a low probability of the attack actually happening. At this point the author does something interesting - he looks forward to a future in which technology will solve this problem, by liberating law enforcement from the Fourth Amendment's restrictions on mass surveillance. He writes:

"The most difficult question to resolve is the one where there is a low probability of a high consequence attack. One day, technology may provide a solution. 278"

Footnote 278 continues:

"278 To the extent that voice-to-text transcription technology for wire communications evolves in the future to a point at which automated processes can accurately screen the content of the communications, the use of such technology, coupled with minimization on the front-end, would prevent any “human observation” of the content of the communications. Compare Google, “How Gmail Ads Work,” available at https://support.google.com/mail/answer/6603?hl=en (“Ad targeting in Gmail is fully automated, and no humans read your email or Google Account information in order to show you advertisements or related information.”) with Orin Kerr, Searches and Seizures in a Digital World, 119 HARV. L. REV. 531, 535 (2005) (a Fourth Amendment search is best described as the process by which “data is exposed to human observation”).

What the author is saying here is that if the government uses a computer to search the content of your phone calls, or your emails, or anything else, for that matter, that isn't technically a "search" as far as the Fourth Amendment is concerned. Therefore, they don't need a warrant. They don't need probable cause. They can just do it. And this argument isn't limited to "Jack Bauer" type nuclear terrorism scenarios. If its not a search, it doesn't matter what they're trying to investigate. This theory would bless the monitoring of Internet communications for any law enforcement purpose whatsoever, as long as it was done by a computer.

This isn't the first time that this argument has been made. Judge Richard Posner wrote something similar back in 2006.

A computer search does not invade privacy or violate FISA, because a computer program is not a sentient being.

Posner goes on...

But, if the program picked out a conversation that seemed likely to have intelligence value and an intelligence officer wanted to scrutinize it, he would come up against FISA’s limitations. One can imagine an even broader surveillance program, in which all electronic communications were scanned by computers for suspicious messages that would then be scrutinized by an intelligence officer, but, again, he would be operating outside the framework created by FISA.

His point, of course, is that FISA should be amended to allow that intelligence officer to access those communications. A computer search "hit" would certainly be enough to establish the "reasonable suspicion" that FISA requires before an intelligence officer can access content. In fact, we might see the argument that a computer search "hit" is enough to establish probable cause. Perhaps it depends on the nature of the search that is performed and how dispositive a match is.

Ultimately, this line of reasoning points the way toward a legal rationale for mass surveillance of the content of telecommunications. In fact, it may be the case there already are secret government programs that are operating under this rationale.

Let me draw this out to an extreme which is hopefully nonetheless illustrative. One imagines a future in which the government has constructed an army of fully autonomous "robocops" which are capable of searching the contents of homes for evidence of criminal activity. Perhaps the authors of this line of reasoning believe that Americans could be forced to submit to random, routine searches of their homes and their personal computers by these robots, because they aren't people, and so when they search your house, its not a search as far as the Fourth Amendment is concerned.

I find that hard to accept, and I also find it difficult to draw a bright line between that scenario and what is herein proposed. I think, perhaps, the interests protected by the Fourth Amendment are a bit broader than a singular concern about embarrassment at the thought of a law enforcement officer viewing one's nude selfies. The Fourth Amendment also protects an interest in being able to go about one's daily life without a constant fear that one's personal effects may be intruded upon and twisted by the hands of an overzealous prosecutor into evidence of criminality. If we're not protected against mass surveillance, frankly, we have no security against that threat.