(Bloomberg Opinion) -- The U.S. Supreme Court has taken an important step away from the “1984”-style surveillance state — barely. The court held, 5-4, on Friday that the government can’t use your mobile-phone-location data to figure out where you have been unless it gets a warrant first.
The big surprise is that Chief Justice John Roberts joined the court’s four liberals to preserve us from a world where the government could track you wherever and whenever it wanted, without probable cause to suspect you of a crime. Most of Roberts’s moments of high moderation have come in decisions that exercise judicial restraint. This one came in the form of judicial activism, interpreting the Fourth Amendment privacy right to extend to a new form of technology, as it should.
Carpenter v. U.S. was so close, legally speaking, because existing judicial doctrine paved the way for courts to permit government access to cell-site location data. Historically, the court has long held that if you share information with a third party, you can’t demand that the information be treated as private.
Thus, the records of which numbers you have called, which are necessarily in the hands of your phone provider, aren’t constitutionally private. (The content of your calls is, though.) That means the government can “pull your LUDs” without a warrant, to use the classic jargon of “Law & Order.”
In the Carpenter case, the government used the data that the defendant’s phone sent to cell towers to triangulate his location, without a warrant. As it turned out, he was close to the location of four robberies at the time they occurred.
The government’s theory was that if your calling information isn’t private, neither is the location your phone sends to your carrier’s cell towers.
Roberts’s opinion rejected that conclusion, holding instead that you have a “reasonable expectation of privacy” in where you are at any given time. He pointed out that five justices had previously taken the view that GPS data could not be acquired without a warrant.
But the truth is that judicial precedent isn’t the key to Roberts’s decision. Social policy is.
Roberts understands that a government allowed to keep track of your location without a warrant probably will. Thus, even law-abiding citizens could effectively find themselves under surveillance, at low or even near-zero cost. The government might start by tracking people it finds vaguely suspicious but cannot track via warrant. But it might easily end up keeping tabs on us all.
It’s striking that Justice Anthony Kennedy didn’t join the opinion. His dissenting opinion fretted that the court’s judgment might endanger other instances in which the government obtains business records without a warrant. And he argued that cell-site location data isn’t geographically precise enough to count as a privacy violation, because it doesn’t track as closely as GPS data. He reasoned, too, that mobile-phone users wouldn’t assume that they “owned or controlled” location data.
That view would be reasonable enough if everyone understood the law of “third-party” privacy or if everyone actually thought through what privacy we have from corporations. But as recent months have shown us, the public is still new at understanding what privacy we have online, and from whom.
Above all, privacy from the government isn’t and shouldn’t be the same as privacy from the providers or platforms we use. Otherwise the privacy compromises we make with Apple and Facebook and Google would lead us to give up privacy from the state.
So why did Roberts make the progressive decision here? One possible, and possibly cynical, reading would be that Roberts is, as usual, deeply concerned about the public reputation and perception of the court.
Had the justices held that we lack privacy in our phone location data, there could have been a public backlash against the court. So when Kennedy wouldn’t provide the fifth vote to the liberals, Roberts stepped in to save the day.
This theory compares Roberts to his predecessor as chief justice (also his old boss as a law clerk) William Rehnquist. A statist conservative, Rehnquist nevertheless famously balked at rolling back the Miranda warnings, reasoning that “Miranda has become embedded in routine police practice to the point where the warnings have become part of our national culture.”
That was a kind of concession to TV norms of defendants being told, “You have the right to remain silent.” Rehnquist didn’t want it said that his court had taken away Miranda rights.
In parallel, Roberts may not have wanted his court to be seen as violating mobile-phone privacy.
The other possibility — not incompatible with the first — is that the conservative Roberts is looking ahead to a post-Kennedy era when the court will have a solid five-vote conservative majority. He might then have to become the court’s most centrist swing voter.
That role tends to move its occupant leftward. It did so for Kennedy and for Justice Sandra Day O’Connor before him. If it ends up having the same effect on Roberts, the Carpenter case may have been the harbinger.
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