Wednesday, September 28, 2016

Tracking Locational Data Via Cell Phones

by Sherry F. Colb

In my column on Verdict this week, I discuss the Indiana court of appeals case of Zanders v. Indiana, which held that police violate the Fourth Amendment if they obtain locational history data about a cell phone from the cell phone user's provider, absent a warrant.  Though the court tried to reconcile its ruling with existing case law, its strongest argument was that privacy would be severely compromised by a doctrine permitting police to gather locational history data about a person without a warrant.

In this post, I want to emphasize something I mentioned in the column:  if gathering locational history data is not considered a search at all (which it appears not to be, under existing Supreme Court doctrine), then innocent people may be subjected to such gathering for no reason at all or for an affirmatively bad reason.  Police may simply decide that they are curious regarding the whereabouts of particular politically unpopular people or groups and can go to cell phone providers to find out what "dirt" they might be able to dig up about their targets.  Because people keep their cell phones with them at most times, tracking the locational history of a cell phone essentially gives the police a running list of all of the places visited by the individual whose phone records they solicit.  This is an enormously intrusive capability, and those of us concerned about privacy against governmental incursion find the prospect of such surveillance Orwellian and frightening.

At the same time, it is useful to remember something about what it means to say that collecting such data does constitute a search.  It does not mean that police can never do it.

Gathering location history about a suspect who may have committed a serious offense can be an invaluable means of proving that the suspect did in fact (or perhaps did not in fact) commit the crime charged.  If calling the collection of such data a "search" meant that police could never gather the data, then it would be understandable that courts would reject the label and say that cell phone location data may be obtained without implicating the Fourth Amendment.

Fortunately, the Fourth Amendment does not prohibit all searches and seizures.  It prohibits only those that are "unreasonable."  Accordingly, if police have good reason to suspect a person of misconduct that can be further illuminated by a look at his or her locational history, then police may accordingly obtain a warrant to search and have the opportunity they want to look at where the suspect has been over a specified period of time.  In thinking about law enforcements needs, then, and balancing them against the individual's interest in privacy against unwarranted intrusion, it is crucial to keep in mind that police do not need carte blanche in order to do their jobs.  When they seek to invade a person's privacy, however, they do generally need probable cause and (often) a warrant as well.  That is all that the case of Zanders and the argument that locational data gathering is indeed a "search" aim to accomplish.


  1. As suggested by the remarks, this sort of "search" (since legally it might be so considered, I use quotes) has First Amendment implications. This also is a reason to change the "third party" rule (see, e.g., Sotomayor's concurrence in the GPS case U.S. v. Jones). Since Kennedy has special concern for 1A issues, including in cases where it might not immediately be apparent to some justices, this could be useful.

  2. @Joe: Please elaborate on the 1A implications.

  3. Prof. Colb in her commentary, e.g., noted:

    "Police may simply decide that they are curious regarding the whereabouts of particular politically unpopular people or groups and can go to cell phone providers to find out what "dirt" they might be able to dig up about their targets."

    Focus on "suspect" associations or expressive activity could have 1A implications, including if religious related. Broadly, the "third party" rule covers phone numbers obtained from phone companies, which also has implications there -- if you know who you call or GPS data at a conservative group's HQ, it has 1A implications.

    The Fourth Amendment in general was partially a result of the government going after certain groups, including to obtain their "papers." John Wilkes, e.g.