Supreme Court Defends Privacy in Cell Phone Location Data Collection

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Publication Date: 
June 22, 2018

Consulting Director of Privacy at the Stanford Law Center for Internet and Society, Albert Gidari, comments on the landmark U.S. Supreme Court’s decision on location tracking in Carpenter v. United States:

The Supreme Court has decided a singularly important privacy case in Carpenter v. United States. The Court ruled that a warrant is required to access historical cell site records — the records that a mobile phone company creates, maintains and even monetizes which show a person’s location as they use or carry their cell phone around. The Court decided that a person has a “legitimate expectation of privacy in the record of his physical movements.”  This was a 5-4 decision, written by Chief Justice Roberts, with each of the dissenting Justices writing separately.

The ink is barely dry on the Opinion, and much will be written about its reasoning, meaning and impact in the days and weeks and probably years ahead, but here are a few observations on the case at first reading.

What a Difference a Week Makes.  The government sought seven days of records from the carrier; it got two days. The Court held that seven days or more was a search and required a warrant. So can the government just ask for 6 days with a subpoena or court order under the Stored Communications Act? Here’s what Justice Roberts said in footnote 3:  “[W]e need not decide whether there is a limited period for which the Government may obtain an individual’s historical CSLI free from Fourth Amendment scrutiny, and if so, how long that period might be. It is sufficient for our purposes today to hold that accessing seven days of CSLI constitutes a Fourth Amendment search.” You can bet that will be litigated in the coming years, but the real question is what will mobile carriers do in the meantime – it could be a long wait for an appellate court to see a criminal defendant whose conviction rests on 6 days of location data, and in the meantime, it could tomorrow when a carrier discloses a week of location data on less than a warrant.  As I said, what a difference a week makes.

Does the Decision Really Make a Difference to Law Enforcement? The dissents were concerned about taking away a valuable tool for law enforcement and making it harder to investigate cases. The location record here was obtained by means of a court order issued after judicial review of an affidavit under section 2703 of title 18, the Stored Communications Act. As some have observed, it is a short step from the affidavit to a warrant application, and in fact, prosecutors are getting warrants for location information today having seen some handwriting on the wall after the oral argument in Carpenter and not wanting to risk their cases. Frankly, if you can make the case for a warrant for seven days of data, the more particular and narrow request for six days or less seems just as easy. The Court also said unequivocally that location data in emergency cases was unaffected by the decision, and in my experience in private practice and as carrier transparency reports indicate, emergency requests for location data are the most common.

Read the full piece at SLS Legal Aggregate