News Analysis: Surveillance: Cozy or Chilling?

LAST year, two literal-minded Supreme Court justices were considering whether police officers needed a warrant before placing a GPS tracking device on a suspect's S.U.V. when they ended up having a rather fanciful argument: What would the founding fathers make of a GPS device, anyway?

To Justice Samuel A. Alito Jr., the question was preposterous: what would be the pre-digital version of a GPS device, he asked? An officer tucked in the undercarriage of a coach? "This would have required either a gigantic coach, a very tiny constable, or both — not to mention a constable with incredible fortitude and patience," he noted in a footnote regarding the case, Jones v. Maryland.

But his partner in the argument, Justice Antonin Scalia, didn't accept the obvious mockery: the image — "a constable's concealing himself in the target's coach in order to track its movements" — is "not far afield," he wrote.

It was a bizarre enough exchange in itself. But beyond the technical details of the case, the justices were essentially grappling over a proper metaphor for digital surveillance. Some people — especially those inclined to be forgiving of new cybertools that can be used for spying — cast the issue in historical terms, seeing the connection between a smartphone and a landline, for instance, or between digital records and the paper records once kept in City Hall.

Those who are more skeptical, however, tend to favor more "1984"-ish imagery. They are not content to say, oh, that's just an algorithm reading my email, a technique Google's Gmail service uses to place ads. Reading for them is necessarily human, even when it is done by a computer. And because of those diligent computers, more third-party reading of correspondence is being done now than ever in human history. Similarly, a smartphone — an unprecedented combination of personal journal, photo album, record library and correspondence desk — becomes something distinctly different from an old landline.

There is ample virtual turf on which to wage this fight over metaphors. For example, there are the software "cookies" that allow companies like Facebook, Amazon or Viacom to track your actions across the Internet. They may be intended to make your browsing experience more focused and useful, along the lines of what good businesses have long tried to do in their stores. But from another perspective cookies seem like an electronic stalker who follows you at the mall from store to store, listens to your conversations and then suggests that you visit a certain pizza place. Creepy.

Google's Street View program, in addition to mapping street-level communities, secretly collected personal data from unsecured home wireless networks. In a recent case, the company argued that the unprotected Wi-Fi communications within a home were like a radio broadcast in that they were "readily accessible to the general public." A federal appeals court panel disagreed with that attempt to justify the collection of personal emails and the like, saying the argument did not conform to the common meaning of radio.

Then there is the recent disclosure of the government's widespread vacuuming up of records of phone calls and electronic conversations. Some, especially at the National Security Agency or in Silicon Valley, might see this as a return to a peculiar kind of small-town values, where everyone knows when you leave your house and the postmaster scans every piece of mail. That's how the Google Internet evangelist Vint Cerf recently put it, reflecting on his own childhood.

Others, of course, would disagree. In revealing parts of the government's surveillance program, the former N.S.A. contractor Edward J. Snowden offered a compelling image of its practice. In a video interview on The Guardian's website, he said that at the touch of a button he and others could look at anyone's email conversation, including President Obama's, "if I knew the email address."

Seen in that light, surveillance isn't quite so small-towny, but remote and potentially nefarious, conjuring a techie in a T-shirt and flip-flops with a super-password that can blow open up the world of online communication.

In fact, the modern idea of privacy can itself be considered metaphorically. If you read a legal textbook on the issue, you see how privacy over time was extended from the house — don't you dare cross my threshold to look at my stuff — to the person. Thus, we don't consider it strange today that a conversation is considered private even if it takes place in a public phone booth, as the Supreme Court long ago ruled. It doesn't matter that we left the protection of our home. (Note to the perplexed: there used to be boxes with phones in them that accepted payment for a call.)

This framing question of "expectation of privacy" is how courts currently determine what government behavior is permissible. And surely our metaphors for new technologies are vital to explaining what we "expect" in terms of privacy.

The Supreme Court will soon consider whether to hear a case about digital privacy — particularly whether smartphones deserve special protection during searches. Among other things, it will be interesting to hear the legal arguments: will the devices be characterized as everyday gadgets, as virtual diaries with a trove of personal data or as tiny constables in our pockets?

Noam Cohen is the writer of the Link by Link column for the Times Business section.