Imagine the police have an arrest warrant for a crime suspect, and they want to find the suspect to arrest him. They happen to know the suspect’s cell phone number, so they want to go to the phone company and have the phone company tell the police the location of the suspect’s phone. The phone company refuses to let the police get that information without a warrant, so the police police go to a judge and apply for a search warrant based on the probable cause to believe that the location of the phone will help them execute the arrest warrant. Here’s the interesting question: Should the judge sign the warrant application and issue the warrant? Or should the judge deny the warrant application?

On August 3, Magistrate Judge Susan K. Gauvey issued a fascinating opinion on this novel question: IN THE MATTER OF AN APPLICATION OF THE UNITED STATES OF AMERICA FOR AN ORDER AUTHORIZING DISCLOSURE OF LOCATION INFORMATION OF A SPECIFIED WIRELESS TELEPHONE, 2011 U.S. Dist. LEXIS 85638 (D.Md. 2011). Her answer: The Judge must deny the warrant application, as location information is broadly protected by the Fourth Amendment and government cannot use warrants to find out the location of people who have warrants out for their arrest. The timing of the case is extremely unusual, as it seems the case is moot and this is only an advisory opinion. If I understand the timing, Magistrate Judge Gauvey denied the application over a year ago, and the government was able to arrest the suspect some other way in the meantime. Judge Gauvey decided to hand down an opinion on the legal issue anyway, appointed defense counsel to argue for defense interests, and now, a year later, has handed down the opinion on why she denied that application back in 2010.

Still, the opinion is obviously intended to be important: It goes on for 172 pages in the slip opinion, or 60 pages single-spaced, and it reaches out to weigh in on a lot of big issues. I also note that her opinion includes excerpts from my recent House Judiciary Committee testimony (see pages 94-96 and 106 of the slip op). So I thought I would blog some thoughts on the opinion. I’ll start with Judge Gauvey’s opinion, then explain why I think it’s wrong, and then turn to a few broader thoughts on the role of magistrate judges in surveillance law.

I. Judge Gauvey’s Analysis

Here’s the basic reasoning of the opinion. First Judge Gauvey creates what a appears to be a new distinction in Fourth Amendment law: a distinction between (a) Fourth Amendment rights in location at a given time, and (b) Fourth Amendment rights in movement over time. According to Judge Gauvey, individuals have a reasonable expectation of privacy in both. There is a reasonable expectation of privacy as to a person’s location if a person cannot be visually observed in that same way. And there is a reasonable expectation of privacy in movements, which Judge Gauvey seems to be taking from the DC Circuit’s Maynard/Jones “mosaic theory” case (which the Supreme Court recently agreed to hear). Judge Gauvey then reasons that if everyone has this Fourth Amendment right, people who have warrants out for their arrest have this right to privacy, too. For that reason, the information held by the phone company as to the location of the phone user is protected by the Fourth Amendment.

Judge Gauvey then considers whether the Fourth Amendment allows a warrant to be issued based on probable cause that the information will help execute an arrest warrant. She concludes the answer is no: A Fourth Amendment warrant requires probable cause that evidence or contraband is located in the place to be searched or that a person who committed a crime is in the place to be searched. Mere probable cause to believe that location information would help the police execute a warrant is not enough under the Fourth Amendment. Judge Gauvey speculates that the Supreme Court would probably allow such warrants if the issue reached the Supreme Court, but she concludes that she “will not take that leap in the absence of any direct precedent or sufficient doctrinal foundation, especially in the face of considerable legislative and public concern and discussion about the invasion of privacy that this new and evolving location technology permits.” Judge Gauvey seems particularly unwilling to issue the warrant in light of all the hearings Congress has had over the past year on how the statutory surveillance law applies to cell-site location: “Against this backdrop of intense congressional inquiry and public concern,” she writes, it is especially inappropriate to sanction an expansion of law enforcement acquisition of location data . . . ”

II. Why I Think Judge Gauvey’s Decision is Wrong

My own view is that Judge Gauvey is pretty clearly wrong. Most fundamentally, I don’t think location information of phones is protected by the Fourth Amendment under Smith v. Maryland, for all the reasons I have explained at length. Part of the problem is that the Fourth Amendment does not deal in abstractions, with categories such as the right to privacy in “location” or right to privacy in “movement.” The Fourth Amendment is much more granular: The relevant question is whether the particular data stored in a particular place on a particular server is protected by the Fourth Amendment, and if so, who is it who has those rights and under what circumstances can that particular information be accessed and disclosed. Given that, Judge Gauvey’s abstract categories produce more heat than light. It doesn’t help that Judge Gauvey relies significantly on the “mosaic theory” opinion that the Supreme Court recently agreed to review.

Assuming Judge Gauvey is right that location information is in fact protected by the Fourth Amendment, then the next question is when the government can obtain a warrant to order the release of that information. This is actually a very interesting question of Fourth Amendment law. Notably, Payton v. New York concluded that “an arrest warrant founded on probable cause implicitly carries with it the limited authority to enter a dwelling in which the suspect lives when there is reason to believe the suspect is within,” and it seems a it strange that the arrest warrant allows the police to break into a suspect’s home but yet there is no ability to even get a warrant to find out the location of the suspect’s phone. Judge Gauvey seems to think that it would require a novel extension of Payton to say that Payton allows a warrant for location information to find the suspect, but I think she has the novelty question a bit backwards: It’s a novel application of the Fourth Amendment to say that it extends to location information, and that novelty sets up the new question of how Payton applies.

What’s the answer? I think this part of the opinion is actually quite difficult, but I would tentatively think that Steagald v. United States is fairly read to allow a Fourth Amendment warrant in this situation. Steagald considered what the police must do when the police think a suspect is in someone else’s home, and they want to execute an arrest warrant of the suspect there. Steagald ruled that the police must obtain a search warrant to do that: They must obtain a warrant to search the home for the person inside to safeguard the Fourth Amendment interests of the people who live there. The basic idea is that the search warrant based on probable cause to think that the object of the arrest warrant will be there makes the search of the place reasonable. The Steagald court was not focused on whether the person in the house was “evidence of crime,” but rather focused on the government’s need to justify the intrusion. Although it’s not an easy question, I think the same reasoning would justify a search of the phone company’s computer for location information of the suspect’s whereabouts to execute the warrant. But as I said, it’s a tricky question — one set up by the novelty of concluding that location information is protected by the Fourth Amendment.

III. A Few Concluding Thoughts

I think this opinion is interesting in two main ways. First, it’s yet another example of the recent practice of magistrate judges using their authority to grant or deny court order applications to hand down very broad opinions on novel issues of how the Fourth Amendment applies to computers and new technologies. I’m generally critical of this development, but it bodes well for those who strongly want the courts to be more civil libertarian in the surveillance law area. Because most judges will grant the applications without an opinion, but will be more interested in explaining why they denied an application, and because any judge can write an opinion at any time on why they are granting or denying the application, this procedure lets a few magistrate judges with very strong views (think Orenstein in New York or Smith in Texas) write opinions on novel questions when they rule on the application.

Although magistrate judges aren’t Article III judges, the magistrates can still submit their opinions to the F.Supp.2d and get them published. As as we see in this case, they can order briefing and submit the opinion over a year after the case is moot. Over time, these magistrate judge opinions are having an impact on the law even though they arise from only a small handful of non-Article III judges in quite unusual procedural contexts. (On that note, I see that over at the Robing Room there is this lawyer’s evaluation of Judge Gauvey form 2006: “She is extremely ambitious and fearless in using the publication of her rulings as a means to raise her profile.”)

Second, this issue is worth keeping in mind for the pending Supreme Court litigation in United States v. Jones, the GPS/mosaic theory case. When the Fourth Amendment mostly protects only invading private spaces, the scope of the warrant authority is reasonably clear: The Fourth Amendment warrant can be obtained to invade the private space for evidence or the suspect. On the other hand, if the Fourth Amendment is read to extend to location information even in public places, then that extension begins to raise new questions of when a warrant can be obtained to access that location information where it has been generated. This is also worth noting for the statutory debate over location information in Congress: As I noted in the passage Judge Gauvey excerpts from my House testimony, probable cause of what is an essential question in applying the probable cause standard.