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Could Better Technology Lead to Stronger 4th Amendment Privacy Protections?

Scholar Orin Kerr explores how the reshuffled Supreme Court might rule on surveillance and policing.

April 6, 2022
Close-up shot of hands using a cell phone

Amend­ment IV

The right of the people to be secure in their persons, houses, papers, and effects, against unreas­on­able searches and seizures, shall not be viol­ated, and no Warrants shall issue, but upon prob­able cause, suppor­ted by Oath or affirm­a­tion, and partic­u­larly describ­ing the place to be searched, and the persons or things to be seized.

Judges, defense lawyers, police and prosec­utors have been fight­ing over the Fourth Amend­ment for 230 years, and it’s not hard to figure out why. So many of the words in the text are vague. “Houses, papers, and effects,” for example, means more today than they did when James Madison draf­ted the Bill of Rights. So, too, does the clause “things to be seized.” What things? Seized how and by whom? Only “unreas­on­able” searches and seizures were barred, remem­ber, leav­ing it up to future courts to argue over what is and what is not a “reas­on­able” exer­cise of police power.

Madison and company knew that some of the ambi­gu­ities contained in the Bill of Rights were neces­sary to achieve the polit­ical comprom­ise neces­sary to ensure rati­fic­a­tion of a docu­ment that changed the way the U.S. govern­ment inter­acts with citizens. The drafters also knew that by these ambi­gu­ities, they were passing on tough defin­i­tional ques­tions to future judges and legis­lat­ors to figure out. The same thing happens today, by the way, when Congress enacts ambigu­ous legis­la­tion and then complains that federal judges aren’t inter­pret­ing it prop­erly. The late Supreme Court justice Antonin Scalia used to complain about that all the time.

The justices over the centur­ies have developed a series of stand­ards they’ve used to determ­ine when a search is a search under the Fourth Amend­ment and then whether such a search is “reas­on­able.” And because tech­no­logy has cease­lessly evolved over the gener­a­tions — police once searched for writ­ten letters and diar­ies, now they also search for emails and text messages — Fourth Amend­ment stand­ards have evolved as well. The law is always catch­ing up to tech­no­logy, and the speed with which it catches up usually is determ­ined by the Supreme Court or Congress.

For some answers about these stand­ards, I turned to Orin Kerr, author and professor at UC Berke­ley School of Law. Kerr is known for his schol­ar­ship on crim­inal proced­ure in general and the Fourth Amend­ment and computer crimes in partic­u­lar, and he’s frequently at the center of legal and polit­ical debates at the inter­sec­tion of tech­no­logy and privacy rights.

COHEN: There is often great frus­tra­tion over the willy-nilly way judges seem to inter­pret and enforce Fourth Amend­ment protec­tions. You wrote a really inter­est­ing Harvard Law Review article in 2011 in which you described an “equi­lib­rium adjust­ment” theory of the Fourth Amend­ment. “The Supreme Court adjusts the scope of Fourth Amend­ment protec­tion in response to new facts in order to restore the status quo level of protec­tion,” you wrote. “When chan­ging tech­no­logy or social prac­tice expands govern­ment power, the Supreme Court tight­ens Fourth Amend­ment protec­tion; when it threatens govern­ment power, the Supreme Court loosens consti­tu­tional protec­tion.”

A decade later, how has your theory held up? Have the Supreme Court and lower courts done more to harmon­ize what some see as cognit­ive disson­ance at the heart of Fourth Amend­ment juris­pru­dence, or has the law grown muddier? 

KERR: I think my theory has held up well. Two of the biggest Fourth Amend­ment cases in the last decade are Riley v. Cali­for­nia and Carpenter v. United States, and that’s exactly what the Supreme Court did in those two cases. In Riley, the Supreme Court held that the search-incid­ent-to-arrest excep­tion does­n’t apply to cell phones. The govern­ment can always search phys­ical prop­erty on a person at the time of arrest, the Court has long held, but under Riley the govern­ment needs a warrant to search a cell phone then. That new rule was needed, the Court said, because apply­ing the old rule to new tech­no­logy no longer made sense: Apply­ing “that reas­on­ing to digital data has to rest on its own bottom.”

Simil­arly, in Carpenter, the Court held that the Fourth Amend­ment protects histor­ical cell-site loca­tion records. This was needed despite the older cases point­ing to the oppos­ite result, the Court reasoned, to “assure preser­va­tion of that degree of privacy against govern­ment that exis­ted when the Fourth Amend­ment was adop­ted." New tech­no­logy of cell phones gave the govern­ment access to a new surveil­lance method, and the Court had to change the old legal rule to ensure that the govern­ment didn’t have too much power.

Of course, some would still find the law muddled. Some might say that Riley and Carpenter made the law more muddled than before. But I would say the law is just really fact specific. How the Fourth Amend­ment applies depends on the facts, and you have to read a lot of cases to under­stand what the rules are.

COHEN: Riley v. Cali­for­nia was decided in 2014 when Justices Antonin Scalia, Anthony Kennedy, Ruth Bader Gins­burg, and Stephen Breyer were on the Court. They are all gone or about to be gone now. Carpenter v. United States was decided in 2018 and the major­ity opin­ion in that case included two justices (Gins­burg and Breyer) who are gone or who will soon be gone from the court. What’s your sense of how the three Trump-nomin­ated justices will push or pull Fourth Amend­ment law in one direc­tion or another? For that matter, what’s your sense of what a Justice Ketanji Brown Jack­son would bring to the debate over the Fourth Amend­ment? Have you had a chance to compare her views with those of Justice Breyer, the man she would replace?

KERR: The over­all effect of these newer justices is mixed, and it prob­ably depends on the specific doctrine. But I can try to offer an over­all take just by running through the new justices. First, Justice Brett Kavanaugh tended to be on the govern­ment’s side in Fourth Amend­ment cases back when he was on the DC Circuit, but then he was the fifth vote (together with Chief John Roberts, Breyer, Elena Kagan, and Sonia Soto­mayor) for the plaintiff in last term’s signi­fic­ant Fourth Amend­ment case, Torres v. Madrid. Second, Justice Neil Gorsuch has a signi­fic­ant liber­tarian streak, which you can see in his separ­ate opin­ion in Carpenter, but he can also end up on the govern­ment’s side in divided cases (as he did in Torres).

It’s too early to tell how Justice Amy Coney Barrett will be in the Fourth Amend­ment area. Finally, I expect Ketanji Brown Jack­son will favor consid­er­ably more expans­ive Fourth Amend­ment rights than did Breyer, who was a swing vote in Fourth Amend­ment cases. Jack­son is likely to be pretty differ­ent. She’s a former public defender, and I would guess she will join Soto­mayor (and perhaps go beyond her) in being most likely to disagree with the govern­ment in Fourth Amend­ment cases. 

In terms of what these new justices will mean for Fourth Amend­ment litig­a­tion gener­ally, I expect many more Fourth Amend­ment cases will be briefed to the justices using origin­al­ist argu­ments. Briefs tend to be writ­ten to the “swing vote,” the justice who is needed to secure a major­ity and there­fore a victory. We don’t quite know who the center votes will be in Fourth Amend­ment cases, but Justices Barrett, Gorsuch, Kavanaugh, and Roberts are all possib­il­it­ies. I suspect we’ll see a lot of origin­al­ist argu­ments being made in Fourth Amend­ment cases to try to persuade those justices. 

COHEN: You wrote a detailed analysis about a first-of-its-kind ruling on geofence warrants and their applic­a­tion to Fourth Amend­ment law. Geofen­cing involves the use of GPS tech­no­logy to create a geographic bound­ary that allows police, rely­ing on Google for example, to track a cell phone user’s loca­tion. The case is out of Virginia, U.S. v. Chatrie, in which a federal judge suppressed the results of a police search warrant because the warrant gathered geofen­cing data from a wide swath of people who could not possibly have any rela­tion­ship to a nearby robbery officers were invest­ig­at­ing. The complic­ated decision raises ques­tions not just about what privacy expect­a­tions people have in the age of loca­tion-track­ing on cell phones but whether new tech­no­logy justi­fies a new way to approach Fourth Amend­ment juris­pru­dence more broadly.

You were skep­tical of the judge’s analysis, and you suggest that such searches may not even be subject to Fourth Amend­ment protec­tions in the first place, but I was struck by what you wrote toward the end of your piece: “One wonders if the possib­il­ity that tech­no­logy can enable the execu­tion of warrants in a more privacy protect­ive way than tradi­tional warrants is lead­ing [U.S. District Judge M. Hannah] Lauck to in effect seek a new Fourth Amend­ment stand­ard that requires warrants to be executed in the most privacy protect­ive way the new tech­no­logy allows.”

Can tech­no­logy at last push Fourth Amend­ment law to a tipping point where federal judges start look­ing for new stand­ards to guide their decisions? I suspect you’ll say that no matter what, these cases will neces­sar­ily be fact-specific, but is there a point where the govern­ment’s use of new surveil­lance tech­no­logy forces changes in the legal stand­ards to which those facts will be applied? And if so, do you have a sense of which justices on the court would be most will­ing to enter­tain such a change?

KERR: I think there are two differ­ent ques­tions. First, can tech­no­logy so expand govern­ment power that the Supreme Court will adjust Fourth Amend­ment rules to limit govern­ment power? My answer to that is yes, and that is the basic idea of equi­lib­rium-adjust­ment that we have been discuss­ing. In the blog post, though, I was address­ing a differ­ent ques­tion: If tech­no­logy permits the govern­ment to access inform­a­tion but also creates the prospect of newer and better privacy protec­tions than have exis­ted before, should the Fourth Amend­ment require those new greater privacy protec­tions?

That’s part of what’s inter­est­ing about geofen­cing warrants, I think. Google can try to get the govern­ment to execute those warrants in a more privacy protect­ive way than warrants have been executed previ­ously. Tradi­tion­ally, search warrants are executed in a brutal fash­ion: The govern­ment breaks in, rifles through everything, and sees everything. It’s a severe privacy viol­a­tion. In contrast, Google can (and wants) to care­fully screen inform­a­tion from the govern­ment, limit­ing what the govern­ment can see and limit­ing the identi­fy­ing inform­a­tion about whose account it is seeing. The ques­tion is, if tech­no­logy creates new ways to protect privacy, should the law impose that require­ment?

As to what the Supreme Court might say to that, the signals are mixed. On one hand, in a case like Missouri v. McNeely, the Court sugges­ted that the ready avail­ab­il­ity of tele­phone warrants these days might make the warrant require­ment broader. As warrants become easier to get, the think­ing runs, it becomes less burden­some to impose a warrant require­ment. That’s not exactly the same. But it’s a little bit similar, I think. On the other hand, the Court has repeatedly rejec­ted any kind of “least intrus­ive means” search require­ment under the Fourth Amend­ment. And that cuts the other way.

COHEN: I want to go back to the Torres case for a second because it addresses, or tries to address, the Fourth Amend­ment’s approach to police use-of-force cases, a topic near and dear to my heart. Torres had to do with whether a suspect was “seized” within the mean­ing of the Fourth Amend­ment when an officer tries but fails to subdue that suspect. And the Supreme Court ruled that the attempt alone to seize a suspect — in that case officers firing at a woman flee­ing in her car — triggered a Fourth Amend­ment analysis. We’re living in an era where there are more lawsuits alleging excess­ive force by police officers, and certainly more taxpayer-funded legal settle­ments paid by police offi­cials, and I’m wonder­ing whether you are seeing the effects of these cases in Fourth Amend­ment law. In other words, how is police reform shap­ing Fourth Amend­ment law?

KERR: It’s hard to tell, as we can’t answer the coun­ter­fac­tual of what the law would look like other­wise. But I’m skep­tical that police reforms are shap­ing Fourth Amend­ment law. George Floyd was killed in May 2020. Since then, the Supreme Court has agreed to hear zero new Fourth Amend­ment cases. That’s remark­able. In a typical term, the Supreme Court hears three or four Fourth Amend­ment cases. This term, for the first time I can recall, it isn’t decid­ing any Fourth Amend­ment cases at all. The Court has also turned away a series of peti­tions asking it to over­turn qual­i­fied immunity, the judge-made legal doctrine used to shield police officers, correc­tions offi­cials, and others from liab­il­ity for their miscon­duct. Justice Thomas has writ­ten dissents from deni­als of certi­or­ari on this, as he wants the Court to recon­sider qual­i­fied immunity. But the rest of the Court has been silent. It’s hard to know, but renewed interest in police reforms might be making the justices less likely to step in them­selves. They may be wait­ing for the elec­ted branches to act. But this is all just spec­u­la­tion. Unfor­tu­nately, we don’t know.

COHEN: Let’s end by look­ing ahead. We know that there will be tech­no­lo­gical advances in the next decade that will affect Fourth Amend­ment law. There always are. Does anything in partic­u­lar stand out to you as some­thing to watch in the years ahead? Do you see the law and tech­no­logy careen­ing toward some flash­point?

KERR: I don’t think there will be flash­points, but I’m expect­ing contin­ued evol­u­tion. The lower courts are disagree­ing on a lot of Fourth Amend­ment issues involving tech­no­logy, and that will likely prompt Supreme Court review in the next few years on those issues. The Supreme Court will prob­ably decide how the Fourth Amend­ment applies to long-term pole camera surveil­lance, if it allows warrant­less border searches of computers, how the private search recon­struc­tion doctrine (which allows the police to view the results of warrant­less online searches by private parties) applies to inter­net providers; what the limits of computer warrants are, and, in the Fifth Amend­ment area, when the govern­ment can force people to unlock their phones. As always, stay tuned!

This inter­view has been edited for length and clar­ity.

This discus­sion is one of several in a Bren­nan Center series on the Bill of Rights. The inter­view with David Carroll about the Sixth Amend­ment is here, and the inter­view with Carol Steiker on the Eighth Amend­ment is here.