Over at Cato at Liberty, Julian Sanchez has an excellent post criticizing and responding to my three posts on encryption and the new Apple iOS8 operating system. The whole thing is worth reading. If you’ve been following my posts, definitely check it out.

Here’s a particularly interesting excerpt, with a paragraph break added:

[T]echnology does not necessarily provide us with easy Goldilocks policy options: Sometimes there is just no good way to preserve capabilities to which police have grown accustomed without imposing radical restrictions on technologies used lawfully by millions of people—restrictions which are likely to as prove futile in the long run as they are costly. But this hardly means that evolving technology is bad for law enforcement on net.

On the contrary, even if we focus narrowly on the iPhone, it seems clear that what Apple taketh away from police with one hand, it giveth with the other: The company’s ecosystem considered as a whole provides a vast treasure trove of data for police even if that trove does not include backdoor access to physical devices. The ordinary, unsophisticated criminal may be more able to protect locally stored files than he was a decade ago, but in a thousand other ways, he can expect to be far more minutely tracked in both his online and offline activities. An encrypted text messaging system may be worse from the perspective of police than an unencrypted one, but it is it really any worse than a system of pay phones that allow criminals to communicate without leaving any record for police to sift through after the fact?

Meanwhile activities that would once have left no permanent trace by default — from looking up information to moving around in the physical world to making a purchase — now leave a trail of digital breadcrumbs that would have sounded like a utopian fantasy to an FBI agent in the 1960s. Law enforcement may moan that they are “going dark” when some particular innovation makes their jobs more difficult (while improving the security of law-abiding people’s private data), but when we consider the bigger picture, it is far easier to agree with the experts who have dubbed our era the Golden Age of Surveillance. Year after year, technology opens a thousand new windows to our government monitors. If we aim to preserve an “equilibrium” between government power and citizen privacy, we should accept that it will occasionally close one as well.

It’s a fair point, well-expressed. My own area is criminal law and procedure rather than the national security context. Speaking only about the context of criminal investigations, my own sense is that changing technology, law, and social practice make it too early to say that there’s a clear shift in the equilibrium in some overall sense. New technologies make some crimes easier to investigate but make other crimes harder to investigate. Different law enforcement agencies have different levels of expertise and resources. The cat-and-mouse game is playing out differently in different kinds of cases.

If Julian is right, though, I don’t think it means that the widespread use of encryption will have no effect on Fourth Amendment law. Even if the increasing use of encryption will help to restore the status quo balance of power, that restoration is likely to have a significant influence in terms of changes not taken. Consider the debate over the plain view exception to the Fourth Amendment. I’ve argued that the courts should eliminate the plain view exception for digital searches because computer searches bring so much information into plain view. It’s an equilibrium-adjustment idea: The existing plain view doctrine gives the government too much power given the new technological facts of computers. If broad use of encryption ends up making it much harder for the government to get access to contents, however, I suspect courts will be less inclined to take away that law enforcement power. Perhaps the same is true for the metadata debate. If the widespread use of encryption ends up broadly limiting access to contents even with a warrant, perhaps courts become less likely to impose new Fourth Amendment restrictions on access to metadata.

Either way, it’s going to be a very interesting dynamic to watch.